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Improving South Rail Corridor by Katerina Boukin B.Sc, Civil and Environmental Engineering Technion Institute of Technology ,2015 Submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Masters of Science in Civil and Environmental Engineering at the INSTITUTE OF TECHNOLOGY May 2020 ○c Massachusetts Institute of Technology 2020. All rights reserved.

Author...... Department of Civil and Environmental Engineering May 19, 2020 Certified by...... Andrew J. Whittle Professor Thesis Supervisor Certified by...... Frederick P. Salvucci Research Associate, Center for Transportation and Logistics Thesis Supervisor Accepted by...... Colette L. Heald, Professor of Civil and Environmental Engineering Chair, Graduate Program Committee 2 Improving Rail Corridor by Katerina Boukin

Submitted to the Department of Civil and Environmental Engineering on May 19, 2020, in partial fulfillment of the requirements for the degree of Masters of Science in Civil and Environmental Engineering

Abstract

. Rail services in older cities such as Boston include an urban system with a mixture of /trolley and heavy rail lines, and a network of commuter services emanating from termini in the city center. These legacy systems have grown incrementally over the past century and are struggling to serve the economic and population growth within the urban center, and increasing needs for mass transit to relieve traffic congestion from the surrounding suburbs. The rail systems themselves were not designed as a coherent system, with variations in power systems, vehicle fleets, block signaling systems, platform, station and even dimensions all inherited from an earlier era. The capacity of the system relies on the state of good repair of the physical assets, but bottlenecks can also arise from physical constraints on space, alignment and configuration etc. One of the major challenges for legacy urban rail systems is to improve services by mitigating bottlenecks and to do so, while minimizing disruption of current operations. This thesis explores the physical causes of bottlenecks for the MBTA Red Line and possible mitigation strategies. The main focus is the South Boston corridor where the Red Line and Old Colony lines occupy a common corridor, abuting a major highway (I-93 SE Expressway). Here, bottlenecks in the Red Line are related to track configuration at Columbia which serves as the sole access point to Cabot Yard, for vehicle maintenance and dispatch, as well as the branch junction for to Ashmont ad Braintree; while services on 3 commuter rail lines operate on a single track. We propose a mitigation scheme that will move the Red Line branch junction to a location South of station, will double-track the Commuter rail (over a 2.6 mile span), and will improve transfers between the Red Line and Commuter rail services at UMass/JFK station. We consider three possible schemes for project construction that allow different rail vehicle access to the Red Line from Cabot Yard, while minimizing disruption of rail through the corridor. The proposed schemes will enable improved headways along the Red Line and increase significantly the capacity of the Commuter rail to accommodate new services for the new line and future services. These outcomes are well aligned with current MBTA strategy to achieve a state of good repair, get the most service out of the existing system, increase the capacity for transit, and expand the reach of commuter rail services.

Thesis Supervisor: Andrew J. Whittle Title: Professor

Thesis Supervisor: Frederick P. Salvucci Title: Research Associate, Center for Transportation and Logistics Acknowledgments

I would like to express my deepest gratitude to my adviser Professor Andrew J. Whittle, for his patience, motivation, immense knowledge, invaluably constructive criticism. His guidance helped during both the research and writing this thesis. I am extremely grateful to Fred Salvucci, for his invaluable guidance to this thesis and for being an inspiration for his goal of improving public transit!

To the transit lab faculty Jinhua Zhao, John Attanucci, Haris Koutsopoulos and Nigel Wilson thank you for the warm welcome, immense knowledge, insightful discussions, and feedback. Their knowledgeable insight was invaluable throughout my research. I am also deeply grateful to Pro- fessor Herbert Einstein who was always willing to give advice and offer help whenever needed. Thank you to all transit lab members for their research input, comments and fun Friday mornings. Especially to Mihir Bhosale, Gabriel Wolofsky, Saeid Saidi, Jiali Zhou and Michael Martello thank you for crucial help and collaboration with MBTA research.

This research wouldn’t have been possible without the support and sponsorship of the MBTA, thank you Laurel Paget-Seekins, Jen Elise Prescott, Erik Stoothoff and others at MBTA OPMI for the help with data and feedback sessions.

Thank you for the endless help and support from MIT and the CEE department, especially Kiley Clapper, Jason McKnight, Suraiya Baluch, Sarah Smith, Max Martelli, Ruth Yiu, and Jeanette M Marchocki.

To Nili, Jennifer, Omar, Bing, Wei, Patrick, Michael, Hao, Ignacio, Ivo, Rafa, Sophia, Eytan, Mihir, Gabe thank you for endless coffee breaks, lunches, dinners, fun moments, help, discussions and generally for being my MIT family!

Finally I am deeply grateful to my family, my parents, my sister Alona, and my grandparents for their unconditional love, support and endless motivation. You inspire me every day to be a better person and strive for bigger dreams. THIS PAGE INTENTIONALLY LEFT BLANK

6 Contents

1 Introduction 23

1.1 Research Motivation ...... 26

1.2 Research Objective ...... 28

1.3 Data Sources ...... 29

1.4 Thesis Outline ...... 29

2 The Challenges of Upgrading Urban Rail Systems 33

2.1 Service Disruption and Congestion ...... 33

2.2 Underground ...... 34

2.3 Evolution of Rail Design ...... 35

2.3.1 Dynamic envelope of ...... 35

2.3.2 Evolving design specifications and codes ...... 36

2.3.3 Resilience and climate change ...... 37

2.4 Impacts on Passenger Behavior Patterns ...... 38

2.5 Historical Conditions in a Dense Urban Surrounding ...... 39

2.5.1 Property challenges ...... 41

2.6 Process of Capital Investment Planning ...... 42

2.7 Public Opinion and Influence of Social Media ...... 43

7 3 MBTA, Past Present and Future 51

3.1 Creation of a Transportation Hub, Boston ...... 51

3.2 MBTA Current Operations ...... 54

3.2.1 Commuter rail network ...... 55

3.3 MBTA’s Near Future ...... 55

4 Analysis of Physical Bottlenecks for Red Line 73

4.1 Introduction ...... 73

4.1.1 Alignment deficiencies ...... 74

4.1.2 Degraded infrastructures ...... 77

4.1.3 Maintenance frequency ...... 77

4.2 Bottlenecks on the Red Line ...... 79

4.2.1 Alewife ...... 79

4.2.2 Southern branch terminus stations ...... 82

4.3 Proximity of and Park Street Stations ...... 84

4.3.1 Proposed solution ...... 85

4.4 Station ...... 85

4.4.1 Proposed solution ...... 86

4.5 Columbia Junction ...... 86

4.5.1 Proposed solution ...... 87

4.6 Charles/MGH Station ...... 88

4.7 Discussion ...... 89

5 Case Study - South Boston Rail Corridor 109

5.1 Introduction ...... 109

5.2 South Boston Rail Corridor ...... 110

8 5.2.1 Key project constraints ...... 111

5.2.2 Proposed rail corridor improvement ...... 113

5.3 Alternative A ...... 114

5.3.1 Stage A2 ...... 115

5.3.2 Stage A3 ...... 116

5.3.3 Stage A4 ...... 117

5.3.4 Impacts on operations ...... 118

5.4 Alternative B ...... 118

5.4.1 Stage B1 ...... 120

5.4.2 Stage B2 ...... 120

5.4.3 Stage B3 ...... 121

5.4.4 Stage B4 ...... 122

5.4.5 Impacts on operations ...... 122

5.5 Alternative C ...... 123

5.5.1 Stage C1 ...... 124

5.5.2 Stage C2 ...... 125

5.5.3 Stage C3 ...... 126

5.5.4 Stage C4 ...... 126

5.5.5 Impacts on operations ...... 127

5.6 Benefits ...... 128

5.6.1 Common benefits of proposed projects ...... 128

5.6.2 Alternative A benefits ...... 129

5.6.3 Alternative B benefits ...... 129

5.6.4 Alternative C benefits ...... 130

9 6 Summary, Conclusions and Recommendations 171

6.1 Summary ...... 171

6.2 Conclusions ...... 173

6.3 Recommendations ...... 173

10 List of Figures

1-1 MBTA Red Line improvement project, with the goal of 3 minute on the Red line system.(Red and Orange lines improvement plan 2019-2025, MBTA 2019 [94]) 31

2-1 Mode distribution of commuting patterns in Boston developed for Go Boston 2030 transportation plan (Go Boston 2030, [78]) ...... 45

2-2 Schematics of dynamic envelope of a tunnel (Railsystems.net 2019) ...... 46

2-3 Map of Cambridge, MA composite natural hazard impact map (Cambridge.gov, 2015) 47

2-4 Full alignment of proposed changes to the I93 and parallel MBTA right of way discussed in this project [38] ...... 48

2-5 view of Savin Hill station area of the proposed new highway and rail alignments (study to expand Southeastexpressway, 2012 [38]) ...... 49

3-1 Alignment and layout of the railway in Quincy, 1826 (Library of Congress) . . . . . 59

3-2 1871 map of Massachusetts, showing the active Rights of Way of different rail com- panies (Walling and Grey 1871) ...... 60

3-3 1905 Map of Massachusetts state showing the rail road marked and the cities with electric street services. (Wilkie and Tager, 1991) ...... 61

3-4 1984 Map of Massachusetts state showing the decline in railroad in the state from 1934 to 1984. (Wilkie and Tager, 1991) ...... 61

3-5 Current map of Massachusetts rail operations, showing MBTA commuter rail, AM- TRAK and other ail active alignments ...... 62

11 3-6 Map showing Boston center, with the alignment connecting to , from October of 1914 () ...... 62

3-7 1925 map of Boston center, showing transportation system network operated by BERy (Boston Public Library) ...... 63

3-8 1947 map of rail transit services provided by the MTA in Boston and adjacent communities (Massachusetts Department of Transportation library) ...... 64

3-9 Current map of Massachusetts commuter rail network, the seasonal rail lines and the South Coast Rail Southern Massachusetts expansion project...... 64

3-10 The of Boston, shows the Red, Green, Blue and Orange lines, as well as other rail and special services () provided by the MBTA (MBTA website, 2020) ...... 65

3-11 MBTA Boston rail transit network dividing by different colors rail links in Boston by the year of their construction ...... 66

3-12 Map of the current Commuter rail network and zoning. (MBTA website, 2020) . . . 67

3-13 A map of the immediate communities west of Boston, showing the new extension and the new 7 stations in a thicker green line, and all the current rail operations marked by their respective line color (Mass.gov 2020) ...... 68

3-14 Map showing the current commuter rail south of Boston and phase 1 addition of the South Coast Rail project. The rail link between Middleborough and East Traunton is a temporary alignment reactivating an existing abandoned rail corri- dor. (Mass.gov, 2020) ...... 69

3-15 Final alignment of the South coast Rail, showing the final alignment of the South Coast Rail . (Mass.gov, 2020) ...... 70

3-16 Example of Vision Rail project alternatives for 2040 regional rail. The shown alter- native, is alternative 6, the most expensive alternative, adopting a full rail electrifi- cation and most of the individual construction and investment projects (i.e Nosth South rail link, fleet expansion, full network etc.) (MBTA website, 2020) 71

4-1 Sources of structural bottlenecks in a rail system ...... 91

12 4-2 Horizontal curve example with definitions for design (Commuter rail design manual , 1996) ...... 91

4-3 Curvature and related formulas (Commuter rail design manual , 1996) ...... 92

4-4 Superelevation equilibrium along a curved track with the inner rail lowered compared to the outer rail (Commuter rail design manual , 1996) ...... 93

4-5 Vertical curvature of track alignment, and difference ...... 93

4-6 Plan of from 1898, with the sharp curvature still part of the current alignment (Wikimedia Common ) ...... 94

4-7 Current alignment of the Green line at Boylston station with the base map of the current urban setting above the station ...... 94

4-8 Red Line maintenance restrictions, Contractor guideline MBTA [87] ...... 95

4-9 is marked in the aerial along with passing Commuter rail tracks south of the station (Esri, 2020) ...... 95

4-10 The schematics of Alewife terminus area, with the isalnd platform, crossover in front of the station and the storage space at the back of the station. (MBTA Blue book, 2014) ...... 96

4-11 Plan of the Alewife, and platform location and the Alewife Brook Parkway . . . . . 96

4-12 Plan and vertical section alignment of the Red line approaching Alewife station . . 97

4-13 Operation of the crossover in front of the terminus station, and its movement, adding passage time to switch between tracks (TCQSM, 2013 [102]) ...... 97

4-14 The most congested roads in Massachusetts, on an average weekday (Congestion in the Commonwealth, 2019) ...... 98

4-15 Examples of structural problems at Alewife garage, with much of the structure leaking, crumbling, or concrete spilling ...... 98

4-16 State of the tunnels behind Alewife platform ...... 99

4-17 Schematics of rail at Braintree station, one serves the tracks, there are no yard facilities ...... 100

13 4-18 Aerial view of Braintree station, including storage tracks for the Red Line and the Commuter rail station ...... 100

4-19 Rail schematics of with platforms on both sides of the station, with a connection between them a floor above the platforms. The tracks continue to Codman yard and connect to the service...... 101

4-20 Aerial of Ashmont station along with the Mattapan connection and Comdan Yard, located south-west of the station. (Google earth) ...... 101

4-21 Ashmont Red line Station and Codman train storage yard. The map shows bound- aries of the properties, the dense residential development surrounding the area, and Park...... 102

4-22 Proximity of Park street and Downtown Crossing Red Line stations ...... 102

4-23 Block signaling system and speed codes for Pask and Downtown Crossing stations (formerly Washington station) (MBTA Block layout and speed commands, 1995) . 103

4-24 Schematics of Park Street station and Downtown Crossing Station existing (a) and proposed configurations ...... 103

4-25 Red Line alignment bordering , inside the map shows the prop- erty ownership ...... 104

4-26 alignment, and the curves on both sides of its approach ...... 104

4-27 Aerial view of Columbia Junction andimmediate surrounding (Looking North) . . . 105

4-28 Columbia junction alignment showing track locations and merger as tracks go un- derground at Andrew portal. (MBTA 1968) ...... 105

4-29 Variation of the headway for Both Ashmont and Braintree branches for the Month of October, between 4pm - 6pm Northbound (Wolofsky, 2019 ...... 106

4-30 A map of showing all MBTA rapid transit lines and their inter- secting stations ...... 106

4-31 Proposed configuration for the Red-Blue connection (Red-Blue connector report, 2018 [65]) ...... 107

14 4-32 Summary of the transit bottlenecks along the Red line, aligning exactly with the structural bottlenecks (Wolofsky, 2019) ...... 107

5-1 Full span of the chosen South Boston corridor, and showing the ROW owned by the MBTA between Andrew portal and Cabot Yard South to Braintree terminus. Marked on the figure, the sub spans A, B, C, split by Commuter rail single ordouble track ...... 131

5-2 Span A - shows the proposed re-designed rail corridor, from Andrew portal to Vic- tory St rail bridge...... 131

5-3 Bridges constraining double tracking of Commuter rail for span A ...... 132

5-4 Full alignment for the proposed Alternative A scheme for the South Boston rail corridor (part a) ...... 133

5-5 Full alignment for the proposed Alternative A scheme for the South Boston rail corridor ( part b) ...... 134

5-6 Schematics of track alignment in South Boston a) current configuration; b) proposed Alternative A ...... 135

5-7 Existing track Alignment in the area South of Savin Hill Station ...... 136

5-8 View of Milton Devaughn Flyover bridge, switching currently between the Braintree branch and Commuter Rail tracks ...... 137

5-9 View North of JFK/UMASS Station, Columbia for the Red line branches ...... 137

5-10 Proposed access to construction sites: (1) Access to the main construction site would be from two different points, depending on stage of construction: east of theMBTA ROW, and between the i93 Highway (2) Through Freeport Bridge utilizing current Commuter rail bridge in order to gain access to the middle of the ROW (3) . . . . . 138

5-11 View of main South Boston rail corridor from Savin Hill Station to Freeport St bridge138

5-12 View of abandoned passage under the Ashmont branch...... 139

5-13 Final proposed alignment at Savin Hill area, Alternative A ...... 140

15 5-14 First stage (A1) of construction for Alternative A - Showing the alignment during this stage of construction and the construction sites active during this stage . . . . . 140

5-15 Second stage (A2) of construction for Alternative A - Showing the alignment during this stage of construction and the construction sites active during this stage and structural elements built ...... 141

5-16 Third stage (A3) of construction for Alternative A - Showing the alignment during this stage of construction and the construction sites active during this stage . . . . . 141

5-17 View of abandoned Conrail box and retaining/wing walls supporting the Ashmont branch ...... 142

5-18 Access to construction zone 1, through Park St ...... 142

5-19 Plan view of Freeport St bridge superstructure plans, overlaid on the current (col- ored) track alignment ...... 143

5-20 State of Freeport St Ashmont branch superstructure. (August 2018) ...... 143

5-21 Plan view of Park St bridge superstructure, overlaid on current (colored) track alignment ...... 144

5-22 Park St bridge North Abutment, under Braintree superstructure. The vertical cracks are marked in yellow ...... 144

5-23 Park St bridge North Abutment, the horizontal crack is marked, and bulging of the abutment is progressing ...... 145

5-24 Double tracking of Commuter rail, Victory St to Park St bridge...... 146

5-25 Track configuration for proposed Alternative B scheme for the South Boston rail corridor (part a) ...... 147

5-26 Track configuration for proposed Alternative B scheme for the South Boston rail corridor (part b) ...... 148

5-27 Final proposed alignment at Savin Hill area, Alternative B ...... 149

5-28 Track configuration for South Boston rail corridor: a) current state; b) proposed Alternative B ...... 150

16 5-29 Cross-section of the ROW, section 1 Alternative B ...... 151

5-30 Cross-section 2- showing of the Commuter rail and Ashmont Red line branch, Alternative B ...... 151

5-31 Section 3 shows the Cabot Yard feeder underpass separated from Commuter rail and Ashmont branch by retaining wall, Alternative B ...... 152

5-32 Section 4 - shows the the location where three separate underpasses for Braintree IB, OB and Cabot Yard feeder pass beneath the Commuter rail tracks, Alternative B152

5-33 Section 5 - At this section the Braintree OB passes under the Ashmont branch to connect at grade with Ashmont OB. Braintree IB is separated from the Ashmont branch, Feeder underpass and Commuter rail tracks with retaining walls on both sides, Alternative B ...... 153

5-34 Section 6 - Savin Hill station platform, the merged Red Line tracks and feeder tracks use pre-existing elevation, while the Commuter rail has still grade separation from the other tracks, Alternative B ...... 153

5-35 First stage (B1) of construction for Alternative B - In this figure we see the alignment during this stage of construction, with marked elements of focus for the stage . . . . 154

5-36 In this figure we see the progress of construction by the end of stage B1 . . .154

5-37 Second stage (B2) of construction for Alternative B - In this figure we see the alignment during this stage of construction, with the structures already completed by this stage of construction ...... 155

5-38 In this figure we see the progress of construction by the end of stage B2 . . .155

5-39 Third stage (B3) of construction for Alternative B - showing the realignment during this stage of construction, with the structures already completed by this stage of construction ...... 156

5-40 Progress of construction by the end of stage B3 ...... 156

5-41 Fourth stage (B4) of construction for Alternative B - showing the realignment during this stage of construction, with the structures already completed in previous stages of construction ...... 157

17 5-42 Progress of construction by the end of stage B4 ...... 157

5-43 Full alignment for proposed Alternative C scheme for the South Boston rail corridor (part a) ...... 158

5-44 Full alignment for proposed Alternative C scheme for the South Boston rail corridor (part b) ...... 159

5-45 Final proposed alignment at Savin Hill area, Alternative C ...... 160

5-46 Track configuration for South Boston corridor: a) current state; b) proposed Alter- native C ...... 161

5-47 Cross-section of the ROW, section 1 Alternative C ...... 162

5-48 Cross-section of the ROW, section 2 Alternative C ...... 162

5-49 Cross-section of the ROW, section 3 Alternative C ...... 163

5-50 Cross-section of the ROW, section 4 Alternative C ...... 163

5-51 Cross-section of the ROW, section 5 Alternative C ...... 164

5-52 Cross-section of the ROW, section 6 Alternative C ...... 164

5-53 First stage (C1) of construction for Alternative C - showing the alignment during this stage of construction, with marked elements of focus for the stage ...... 165

5-54 Progress of construction at the end of stage C1 ...... 165

5-55 Second stage (C2) of construction for Alternative C - showing the alignment during this stage of construction, with the structures already completed by this stage of construction ...... 166

5-56 Progress of construction at the end of stage C2 ...... 166

5-57 Third stage (C3) of construction for Alternative C - showing the realignment during this stage of construction, with the structures already completed by this stage of construction ...... 167

5-58 Progress of construction by the end of stage C3 ...... 167

18 5-59 Fourth stage (C4) of construction for Alternative C - showing the realignment during this stage of construction, with the structures already completed in previous stages of construction ...... 168

5-60 Progress of construction by the end of stage C4 ...... 168

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20 List of Tables

2.1 MBTA four rail operation dimension requirements ...... 50

4.1 Commuter rail geometric design requirements ...... 108

4.2 Statistical station occupancy results - only above 3 minute headway ...... 108

5.1 MBTA South Boston Rail corridor demand ...... 169

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22 Chapter 1

Introduction

The Boston metropolitan region faces big problems with its rail systems: within the city some of the lines are at capacity and need frequent maintenance due to deterioration and aging of the infrastructures, while commuter rail lines do not adequately cater for the current passenger demand or future growth. We need a holistic view of the needs of mass transit services for a metropolitan city such as Boston, that should not focus on isolated renovation project, or the needs of a single rail line, but try to incorporate a larger perspective on the full (regional and local) transit needs to optimize the very limited availability of space in an already dense urbanized area.

Today when the backlog for infrastructure renovation projects and expansion projects for rail transit operations is reaching an all time high both on the national level and with , in particular, one of the greatest needs is to improve rates of project execution. This will ensure the safety of rail infrastructure and reduce risks of loss of service due to structural failures [48,115]. The challenges for any capital investment construction project to get approved, funded and executed are tremendous, especially for public transit infrastructure, and are much larger if the construction affects a critical commuting corridor or disrupts access to the city center.

In South Boston, the Commuter rail and Red Line share a common rail corridor bounded by development on both sides and are experiencing critical bottlenecks for their current and future operation needs. With their combined station at JFK/UMass being in-accessible for easy transfer between rail systems or Red Line individual branches. The Commuter rail operates on a single track along the corridor, which constrains the capacity for its 3 existing lines, and is expected

23 to absorb services for the new South Coast rail line (currently under construction with a budget of $1B for current phase 1). Columbia junction serves as the sole access point to Cabot Yard, for vehicle maintenance and dispatch, as well as the branch junction for trains to Ashmont and Braintree. This is an area with severe train congestion, where delays on NB operations propagate along the entire line. It is also an area susceptible to flooding and requires frequent maintenance due to the state of degradation. A substantial Red Line system upgrade is ongoing (new fleet and signaling system) with the anticipated goal of providing 50% higher frequency of service after its completion. It is challenging to perform changes in configuration or disruptive construction work for a legacy rapid transit system in a dense city. With the completion of the projects for the Commuter rail and Red Line, the bottlenecks will become more acute and much more difficult to solve.

This thesis proposes a new, more holistic approach for identification and synergy of construction projects, relating individual projects to local and regional needs. There are numerous advantages of integrating projects within a specific transportation corridor including - optimizing for overall project costs, construction time, minimizing operational impacts and improving execution rates of priority projects. This thesis proposes a new scheme for the South Boston rail corridor covering a 2.6 mile span that integrates a number of concepts: 1) mitigation of bottlenecks for current commuters and those that will arise in improving its regional rail network; 2) linking the Red Line problems at Columbia junction with the train operations at the merge of the Ashmont and Brain- tree branches; 3) need to improve Red line network frequency while maintaining full operations along the most used rail line in Boston. The proposal addresses existing rail bottlenecks for both Red Line and Commuter rail systems, infrastructure renovation (state of good repair; SGR) at the MBTA, and minimizing impacts of construction on rail operations. For this capital investment project both rapid transit and Commuter rail will benefit from improved capacity, together with many infrastructure renovations and track alignment changes. With current practices addressing each rail network or even each infrastructure renovation as-stand alone construction project , this thesis offers a new paradigm for improving high capacity rapid transit networks while keeping full services and quality of service to its passengers.

Population growth in large urban cities (New-York, London, Paris, Boston etc.) over the past 50 years has concentrated development in very dense commercial business districts (CBD) that

1Total SCR project cost currently estimated $3.2B (2019) [66]

24 supported by transportation, water, power and communication infrastructures. The reality of very dense infrastructures with their high and growing usage, economical importance and inter- dependency for the whole metropolitan create the ever growing challenge for maintenance, reno- vation or expansion that might disrupt the current urban fabric.

This thesis focuses on rail rapid transit of Boston. Greater Boston has a long history of providing public transportation. In 1630 there was already a service connecting Boston to Roxbury and surrounding towns. By the the 19th century there were a number of street running chartered public and freight rail transportation carried by horses or steam railroad operation provided by tens of different private companies. In 1892 the city ran into its first infrastructure bottleneck dueto street car congestion on , forcing the state of Massachusetts to make changes [108]. The chosen solution was a network of 4 elevated and underground rail lines. These urban rail networks including the first tunnel in opened in 1897. The tunnel is stillused today, as part of the central core of the Green Line light rail line, operated by the Massachusetts Bay of (MBTA).

The MBTA is the public transit agency that was formed in 1964 to provide all of Greater Boston’s transportation. The new MBTA included the former public agency, MTA, and added most of the bus companies, and commuter rail lines over time. Most of the current MBTA transit Right of Way (ROW) existed and was operating at the time the agency was formed, posing a challenge to the ability to design or rebuild a more efficient rail network to improve for connectivity and align with passenger demand. The MBTA operates on inherited system of geometrically constrained and historical rail corridors with old infrastructures (some more than 100 years old). The need for state of good repair projects or routine maintenance grows and now affects most aspects of the system.

In order to design and execute any construction project effectively in a dense urban environment, there is a pressing need to change the way projects are materialized and designed. The current process uses a narrow view of single proposals that are promoted through an internal project ap- proval process for inclusion in the rolling five-year capital investment plan (CIP). This is inefficient especially when understanding the full extent of construction renovations and expansions needed to provide safety of rail infrastructures and facilities, while providing high quality reliable trans- portation services. The current scale of state-of-good-repair (SGR) projects or any of the regional

25 or local rail capital investment projects is rising in the past few years, but is not fast keeping pace with the needs of the whole system.

A more holistic approach view of project identification requires coordination between urban rapid rail transit and regional rail services, adding perspective not featured in construction; needed for constrained critical right-of-way corridors. This type of project design, is well illustrated by the proposed case study for the new South Boston rail corridor combines changes for both the Red line and the Commuter rail networks and resolves multiple problems for the two networks.

1.1 Research Motivation

The MBTA currently faces massive delays in funding, impacting its existing backlog of state-of- good-repair projects (estimated at $10B at 2019 [18, 55]). The most heavily used MBTA service is the Red Line that has seen passenger ridership increase from 175,417 riders per day (on a week day) in 1997, to 217,325 in 2013 [81] to 240,000 at 2019 [93]. Ridership is expected to grow with the introduction of the new rolling stock (2020-2021) and service is expected to reduce rush hour headway to 3 minutes. Future projections for greater Boston show expansion of the metropolitan area [57,88]. There seems to be a clear indication of a growing gap in the expected performance of the rapid transit system (including its passenger capacity). The MBTA system is experiencing a significant deterioration of infrastructure and a growing list of deferred maintenance. Thesystem has the second worst rate of derailment incidents in North America [45], and frequent disruption of rail services. These problems are connected with the state of infrastructures along the system and show the urgent need of actions to improve safety, reliability and quality of transit services [69].

As the infrastructure gaps have become more apparent in the last few years [18,55], the MBTA along with the state of Massachusetts have been trying to push forward as many large capital investment projects as they can in their 5 year CIP and long-term 2040 projection plans [89, 90]. The "immediate" (5 year) MBTA plan includes $8B investment in the Red Line, including the purchase of a new fleet of subway trains and a new signaling system which is currently in progress [10, 88]. With this investment project, the MBTA is trying by 2025 to improve service reliability, the frequency to a 3 min headway (a 50% service increase) and to accommodate for the changes in demand and quality of service [94]. Figure 1-1 shows the timeline and goals for the for the vehicle

26 and upgrade project.

There are many challenges for achieving 3 minute headways associated with the track align- ments, state of infrastructure, structural deficiencies and signaling system. The current Red Line improvement project does not consider bottleneck assessment with the physical layout of infras- tructures. Wolofsky, (2019) has shown that the current Red Line network alignment configuration and signaling system do not sustain a 3 minute headway along several segments of the alignment (and is barely sustaining the current 4.5 min headway).

The MBTA currently operates a Commuter rail network, providing relatively low frequency service to the greater Boston area, including 3 separate services operating along the same rail corridor with the Red Line in South Boston. A new rail service is planned Between Boston and New Bedford and Fall River (South Coast Rail)) and is already under construction. This expansion will add both stations and passengers to the ROW in the South Boston corridor [118]. Though this project would improve regional connectivity, its current configuration leaves a corridor of 4 rail lines operating on a single track for both inbound and outbound routes [70]. Current operations have reached maximum frequency along the corridor with total of 4 trains per hour along the corridor. With a continuous rise in passenger demand [37] in recent years, and an even further projected growth [72,78] current operations will be unable to absorb operations for SCR expansion or future existing lines frequency growth (desired regional rail future frequency is 15 minute headway for each of the 4 lines [72]).

Realizing that the current structural state of the Red Line network has several structural bot- tlenecks affecting the 3 minute headway goal, the constrained Commuter rail operations andclear need for changes of the South Boston rail corridor. The improvement and expansion for both rail systems and their infrastructures to enable a frequent regional rail service, reliable high frequency rapid transit and accommodate parallel MBTA projects directly impacting services are needed today. With the added changes happening with time to our available construction, configuration and budget opportunities.

The thesis reviews the general historic growth of the city and the interaction of that growth with the development of passenger rail services. It then considers the current challenges of the Red Line and the and focuses on the particular spatial challenges in Dorchester (South Boston rail corridor), developing three different alternatives to solve the problem of delivering a2

27 track Old Colony operations through Dorchester, reducing Red Line Columbia junction congestion, combining rail services at a single JFK/UMass station without significant disruption to Red Line Services, and recommends that one of these be selected by MBTA and added to the South Coast Rail contract for implementation.

The current research work has been done in collaboration with Gabriel Wolofsky (MIT) and Jiali Zhou (), on the transportation bottleneck identification and validation, and the Red line simulation tool that would be able to assess ahead of time any structural changes and their impact on headway and operations with high certainty. While the identification focus is a challenge associated with physical bottlenecks, the research lighting the potential advantages that can be achieved by a more holistic views where multiple projects could be addressed to reduce or potentially reduce construction costs.

1.2 Research Objective

The main objective of this research is to demonstrate the need to integrate comprehensive consid- erations of spatial constraints in the achievement of multiple objectives for improved rail services. We analyze how changes in physical infrastructure along a rail corridor (track alignment and fa- cilities) are able to help the Red Line to operate at a higher frequency (target 3 minute headway). Planning a feasible construction staging to both mitigate the bottlenecks (improving system ser- vices) for the rail systems while complying with all limiting constraints given by the agency to and allow an optimized design to execution process.

The current proposal to address bottlenecks in the South Boston rail corridor is to be used in ongoing research on Red line operations by Zhou (PhD, in progress). Developing a new transit simulation tool that would account for structural deficiencies, quality and reliability of operator dwell times. The new tool would be able to identify the best future designs and validate potential headway reduction or delays, associated with the geometry, capacity and state of infrastructures in a rail network.

28 1.3 Data Sources

The data used in this thesis was obtained either from public records (online) or received directly from the MBTA. The MBTA includes embedded geo-referenced CAD files for the Red Line align- ment and infrastructures, along with the scanned as-built plans of most of the Red Line facilities (dated from most recent construction or renovation). As so many of the facilities are very old, there are gaps in information for some structures and in the subsurface information. This data was very helpful to understand the background and challenges affecting construction. By coupling the structural data from the MBTA with the data from the transit bottleneck analysis (ODX, demands, station dwell times, headways , incidents, delays etc.) we were able to gain a better understanding of the added passenger factors constraining the bottlenecks and understand better the needs and constraints for improvement of the Red Line.

The public record data include protocols, codes for design and construction, procedures for project identification and the CIP process (through to contractor released public bids). The project also uses ArcGIS open source data and data parcels from Massachusetts official website to help design the South Boston case study rail corridor changes, and the operation construction staging with full access and working sites breakdown. The assumption used for this thesis is that when combined with accurate MBTA data, the boundaries and usage areas are currently defined for assessing the feasibility of design and construction.

1.4 Thesis Outline

Chapter 2 discusses the growing list of challenges affecting capital investment project identification and design in a dense, growing urban environment, including the impacts they have on final con- struction project execution. This section emphasizes project constraints that affect identification, design and construction execution form ( staging, site location, material use etc.). The complexity and impacts of these project constraints only grows when considering the fast pace of metropoli- tan developments and the inter-connectivity of infrastructures. The purpose of this chapter is to depict the inter-connectivity and complexity of constraints on capital investment projects with urbanization. These especially affects legacy systems (such as transit systems) that have bounded

29 rights-of-way. The chapter shows the need to change the project identification, design and approval process to provide a more holistic view of the system in-order to maximize benefits system-wide and accelerating project execution rates (overall time and costs).

Chapter 3 reviews the history of the MBTA and development of rapid transit in the Boston area. The historical legacy of the evolution of rapid transit rail network in Greater Boston explains the lack of well-planned rail network due to the uncoordinated development, multiple operators and rail company owners, along with numerous active alignment changes and corridor abandonment.

Chapter 4 focuses on the analysis of the current Red Line. We identify the physical bottlenecks and provide a preliminary assessment and mitigation options. Given that each identified bottleneck also has various constraints challenging any proposed improvement project at any location along the Red Line, for each bottleneck mitigation project the holistic view of needs and on going operation for both the local and the regional rail network is considered.

Chapter 5 focuses on the redesign of the South Boston rail corridor and its construction staging to improve both the operations of the Red Line and to add new services on the Commuter rail lines. This chapter proposes three different staging alternatives for constructing the project, the scope comprised by several stand alone projects, structural changes, together with double tracking the Commuter rail over a span of 3.6 mile.

Chapter 6 summarizes the advantages of the proposed alternatives for the South Boston corridor, and provides recommendations for further work.

30 Figure 1-1: MBTA Red Line improvement project, with the goal of 3 minute headway on the Red line system.(Red and Orange lines improvement plan 2019-2025, MBTA 2019 [94])

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32 Chapter 2

The Challenges of Upgrading Urban Rail Systems

The drastic rise in urbanization over the last 70 years (4.2B people now live in cities compared to 0.75B in 1950) represents an overordinary challenge for the development of supporting infrastruc- tures. Upgrading of urban rail systems is of particular concern as they provide the most efficient means of mass transit, but upgrading is severely constrained and existing systems must deal with degradation and lack of maintenance that impact urban mobility.

2.1 Service Disruption and Congestion

Commuting corridors (for both the public transit and private vehicles) are essential means for access to the commercial business districts of large cities, and are critical to the economy of the regional urban centers. Rail corridors have the highest passenger volume compared to other transportation modes and the impacts of disruptions or closures (for construction projects etc.) cause significant economic disturbance and add to the problem of traffic congestion [6].

The city of Boston was considered the 9th most congested city in the world in 2019 [50]. In North America, it is the most congested city out of 60 urban considered in the INRIX study [50], costing the city more than $4.1B per year. The city is a regional hub; 60% of peak hour commuters originate from outside the city, and 33% of all commutes are done using public transit [78]. Figure 2-1 shows the data for commute to and from Boston for work, used as basis for the "Go Boston

33 2030" public transportation vision [78]. The problem for Boston is the severe congestion to enter the city, while the public transportation alternatives are very limited, compared to cities with larger, more frequent regional rail services such as Paris and London. If the regional rail systems were improved (expansion, frequency and quality of service) it could mitigate congestion in Boston. The economic cost of rail line (or critical highway) major shut-downs (for even a day) leads to a very constrained ability to perform any type of construction along the different rights of way. The cost of congestion in Boston, is already considered at an average of 149 yearly hours per citizen ($2,205 per person), which accounts for direct and indirect costs of the time loss [50]. The cost and congestion repercussion of shutting down the public transit for any planned construction are large, creating time delays to the project approval process. It should be noted that with high wear and tear along heavily used rail lines (i.e., accelerated degradation) can affect the whole rail network, and its ability to support high quality services (i.e. higher probability of failures and rail incidents ).

When there is a large backlog of degraded infrastructures service will decline and the system is prone to failures (especially during an extreme storm event). In February 2015, MBTA experienced three large snow storms, causing a full shut-down of public transit (bus, transit and rail) leaving roughly 1 million people without commuting options [43]. The cause of this severe breakdown and inability to provide service during the most needed time, was attributed to aging infrastructures and vehicle fleets caused by decades of under investment in the system, creating a back-log of $3.3B in state-of-good-repair projects [41]. During this period, the MBTA lost tens of millions in revenue and a similar amount in immediate maintenance needs. It subsequently invested $100M into winter resilience systems, significantly improving winter storm performance over the last5 years [101].

2.2 Underground Infrastructures

As all western countries have seen urbanization over the last 50-70 years, current projections show that over 70% of the world’s population will live in large cities by 2050 with the expansion of existing large cities into mega cities [57] [124]. Densification of well-established CBD areas is a common feature of the urbanization process, and a critical issue. In central locations, the underground rail networks (metros) are often dense and effectively depending on stations between lines.

34 For example Figure 3-11 shows the density of underground rail lines, and interchanges in downtown Boston, comparing to the low rail density reaching the adjacent suburbs. It is often difficult to perform renovation on underground rail lines without creating major service disruption, while system expansions involve large costs and high risks associated with underground construction. System expansions in many densely constructed city centers would never be achieved due to lack of underground space for construction [109]. Boston has a long history in addressing this challenge. The (CA/T) project involved construction of underground highways below the dense downtown area while continuing to operate the established road system [46,62]. Urban construction always involves regular disruptions of the commute of the city (detours of traffic etc.). In Boston the CA/T caused more than 15 years of traffic disruption in the most densely developed partof the city. In contrast earlier urban re-development projects such as Plaza involved significant demolition within the city center [13].

An emergency problem is the closing physical availability and access to subsurface space for new underground infrastructures in well established CBD areas of large cities. The underground space is used widely for a range of infrastructures including: sewer, water, electricity and communication cables, rail road and ventilation tunnels, underground parking etc. When designing today any structural changes (either for new or existing rail infrastructures), must account for the challenges of creating a subsurface corridor for new tunnels/stations and the challenges of construction staging to minimize impacts on existing above-ground infrastructures and buildings.

2.3 Evolution of Rail Infrastructure Design

2.3.1 Dynamic envelope of tunnels

Existing rail tunnels are likely to remain in their current geometric configuration (i.e. track cur- vatures height and width) creating a permanent constraint on rail vehicles and power systems (fleet type, electric etc.) and on going operation. Dynamic (lateral and vertical) movements of rail vehicles are related to speed and alignment (curvatures), and that limits geometry can cause lower track speed or dictate vehicle fleet dimensions (Figure 2-2 shows a schematic of the dynamic envelope related to vehicle geometry). For the MBTA system, the Orange, Blue, Red and Green

35 lines are all incompatible, preventing sharing of tunnels or vehicles and forcing the MBTA to main- tain 4 different vehicles fleets with different maintenance approaches due to the different natureof operations for each line [10] [14]. Table 2.1 summarizes MBTA line differences, while the physical differences are very small, the cost and permanent operation challenges are large. Inlargewell established rail systems, it is practically impossible to expand existing tunnel dimensions, imposing another long term challenge on the ability to improve/optimize operations or reduce their costs.

2.3.2 Evolving design specifications and codes

General design requirements for infrastructures have become more demanding to ensure safety, accessibility, maintenance and/or passenger comfort. Upgrades or renovations are required to comply with current codes. For example the Americans with Disabilities Act (ADA, 1990) required equal access to public transit. The MBTA system underwent large expansions and renovations in the 1970’s and 1980’s that were designed and built already with compliance with the act [84]. The 2005 MBTA/BCIL settlement agreement pushed forward mahor changes to station, transit and bus accessibility across the system, with a long term transformation plan [39]. Today, on the Blue line and many stations along the Green line are not accessible, as are many of the Commuter rail stations [82]. Renovations of the Commuter rail stations to improve accessibility are continuing, with over 75% made accessible by 2014 [81]. As for the Green Line, many of its station are still inaccessible, with a new 2018, $8B Green Line transformation plan that includes a new accessible and larger capacity fleet for the Green Line, many station accessibility projects and facility upgrades are expected by 2030 [83].

For other design criteria (e.g. structural requirements) existing structures are only required to comply when there are renovations or structural expansion projects. There are many challenges and constraints preventing or delaying, as in the accessibility rail stations completion (apart from budget), highlighting inability to change existing infrastructures for space, geometry or operational reasons. For the completion of any new mandatory requirements to over 260 existing rail and transit stations adds a large queue of construction projects to existing capital investment plan (CIP), needs for changes in allocated funds and requires a decades of time to complete.

36 2.3.3 Resilience and climate change

Global and regional climate change requires a re-assessment of long term trends (such as sea level rise) and extreme hazard events (coastal flooding, extreme rainfall etc.) and new impacts on infrastructure assets across the entire urban area. Transportation infrastructures such as tunnels and bridges, are both crucial for connectivity and mobility. They are key elements in design criteria for catastrophic situations (e.g. emergency routes during hazard events [19]) [74]. The resilience of any city relies on the safety and performance of critical infrastructures, and their ability to continue function to prevent loss of life and property damages during hazard events [19, 33]. The 2000 Disaster Mitigation Act from FEMA stimulated states and cities to develop local multi- hazard mitigation plans, with a five year update cycle, in order to be eligible for federal grants for mitigation plans and emergency disaster relief funds [36]. In recent years there have been two driving forces impacting the mitigation of natural disasters [2, 79]: The first is the progress in our abilities to analyze stochastic hazards and to couple these events (e.g. occurrence of both an extreme rain event and coastal flooding) at city scale show the economic risks associated with prolonged connectivity loss. [74,76]. The second is the time-scales for achieving city scale resilience (to address long-term sea level rise and storm intensity), through completion of construction for mitigation projects [3]. The adaptation to climate change needs is growing challenge to most large coastal cities [3]. The emerging need for new construction projects to mitigate potential catastrophic failures represents another factor to consider in project priority action.

In the Massachusetts Bay area, the Metropolitan Area Planning Council is responsible for the regional mitigation plan, and approves the local multi-hazard mitigation plans. The state experi- enced 16 natural hazard disaster events between 1991 and 2015, with the most severe economic, life and property risks at the Boston and its inner suburbs [79]. The city of Cambridge, separated by the from Boston, where a large portion of the underground stations of the Red line are passing, is a good example for a multi-hazard mitigation plan, showing the vulnerability of the MBTA rail network within it. Figure 2-3 shows the map of the composite hazard risks in Cam- bridge (i.e. snow, storm, hurricane, flood etc.) and projected high risk areas and critical structures. The two areas with the highest risks include the Alewife terminus station and the Kendall/MIT station for the Red line. Both stations and tunnels are vulnerable to flooding at current city scale configuration and multi-hazard predictions (i.e., susceptible for damage due to 4-5 different types

37 of natural hazardous events of high occurrence probability 1 and 4 grades of intensity in analysis), the potential long term impact to Red line operations and infrastructures creates the priority for the city and MBTA to address this through resilience improvement projects. Coastal flooding is especially important for MBTA (having implications to its infrastructures through many local and the Boston regional hazard mitigation plan) given the current vulnerability of the Blue Line tunnels and future impacts arising to the system.

The MBTA identified and approved Capital Investment Program is growing, at a higher ratethan the agency is able to keep up. Many of those projects, that are delayed, waiting budget approvals, or deemed too disruptive for ongoing operations (such as the execution of the North-South rail link in Boston more than once since the project was designed [40]), may be the vulnerable links to cause long connectivity loss disconnecting the network. The connectivity nature of the urban city areas, effective flooding mitigation for the area involves collaboration of local city project planning and state agencies projects, as all projects impact each other.

2.4 Impacts on Passenger Behavior Patterns

Transportation planners discuss the impacts on demand associated network disruption to public transportation systems. When considering a long duration project involving a rail link or station closure, there is delicate balance between anticipated disruption to operations (and their duration) with potential long-term negative impacts on service demand [20,31]. The nature of the disruption to operations could be both from a planned project or an infrastructure or facility failure requiring prolonged repairs. The rail network has a relatively low robustness compared to the road network due to the lack of redundancy, which presents large challenges when stations are closed (potentially disconnecting large portions of a rail line) [20]. Research has shown that people have a routine commuting pattern, once this is disrupted they will adjust temporarily, and will return gradually to their initial pattern [9, 20, 34]. However, after they adapt and adjust to their new route, they might not be revert to the prior service, depending on the time span of disruption. This planning of permanent demand is unique to large projects and transit alternatives [34]. The change in demand could be attributed one of two changes either the move to private vehicle option or to other available public transportation mode, or people will even change their home or work location [9] [28].

1events with more than 20% of yearly occurrence.

38 Zhou at al. 2010 [111] analyzed large incidents (i.e. bridge collapses, road closures and public transit strikes) causing road and rail closures for a span of days to a few weeks, and their impacts on short and long term passenger behavior (the case studies were taken from large cities from across the world and several case studies within the US). In a more recent example, the Washington D.C. metro had significant work done to its network as part of SafeTrack project, with 16 long duration track segment closures between June 2016 and June 2017. The project was intended to restore a large under-invested system into a state of good repair [42]. Researchers analyzed rail passenger behavior in D.C. during and after the severe service disruption (between 6/2016 and 3/2017) through surveys of changes of commuting routes. The result found that 36% stated they would either change transportation mode, cancel their commute or change destination before the first shut down. Before the second shutdown, the percentage of passengers changing their commute was 61%, a follow up after construction phases ended revealed that even a larger portion of commuters changed their daily patterns [112]. The rail demand in D.C. has been declining for years (along with safety and reliability), but the dramatic decline during the year of construction, led to large revenue losses across the system [99], and has continued to decline over the subsequent years [42]. The balance between passenger impacts and needed construction is very hard to predict, and it is especially hard to relate this to construction time span or cost, creating a challenge for the transit agency in choosing the best alternative of design.

Experience in many agencies shown that for short periods of closures, mitigation of disturbance by allocating an alternative service for passengers, would be accepted [9, 34]. Potential passenger impacts should be receiving much higher weight in design planning, and construction staging should aim to minimize impacts on passengers. Bhosale [75] analyzed mitigation of passenger disturbance for planned service shut downs. The thesis showed the importance of considering the passenger origin and destination commuting patterns in designing alternative services during rail shut downs. To reduce passenger dissatisfaction with long-term, weekend shutdowns and to improve the connectivity quality of alternative service provided during the shut down period.

2.5 Historical Conditions in a Dense Urban Surrounding

In most transportation systems today, the right-of-way for underground rail lines and stations will be designed below roads within dense urban centers rather than beneath buildings [102] (with few

39 exceptions such as the recent Crossrail project in London [25]).

When the ROW is at grade, rail corridors are often parallel to and bordering highways and arterial roads leading to the city center. Away from the city center in more residential areas, the rail ROW is either bounded by roads (on both sides) or bounded between the road and residential buildings. Restrictions on the rail right of way, its supporting infrastructures and facilities presents a growing constraint on accessibility challenges for renovation and maintenance across large systems affecting many urban rail networks. While it is feasible to construct on a right-of-way accessing it from a road (if road shutdown approved), it is often not possible to create construction site access through existing buildings, limiting even further construction options in a dense urban area. Moreover, with the existing urban developed properties, rail tracks often pass in close proximity to residential structures, any rail incident could cause grave impacts and damage.

Major renovation projects inevitably involve disruption to travel services and hence, creative mitigation measures must be part of the planning process. We need a more holistic approach to our project design and construction to balance the existing built challenges with the needed state-of-good-repair and system expansion.

Some of those challenges are illustrated by a recent expansion study for the I-93 [38], a project that was approved for preliminary design in 2015. The project aimed to create an extra lane in each direction of I-93 in South Boston, to reduce congestion [95] . Figures 2-4 2-5 show the design proposed for the project, tunneling the rail ROW west of the I93, for both the Red line and Commuter rail line, to create space needed. The solution proposed improvements for the Commuter rail by double tracking, It also proposed closing both the highway and the rail right-of- way for months during construction (no time frame was given but construction was cast in-situ, cut and cover box tunnel sections beneath I-93 for MBTA rail lines). The proposed design did not account for existing subsurface structures in the vicinity of the alignment (including three large bridges, and city subsurface infrastructures). The study has never been advanced, likely because of the excessive disruption involved for both rail and vehicle right-of-way.

40 2.5.1 Property challenges

The historic rights-of-way for older rail systems are very challenging to renovate today. The con- tinuing urbanization process constraints the ability to expand rail facilities and routes. Increasing density of urban development (after expanding from a central CBD or from multiple cities) create the need for improving public mass transit systems and services but is constrained in the avail- ability of land for transit development. Public transportation agencies today, acquire/receive land for rail operation (or for supporting facilities) from either private holders or from the state. For expansion projects, transit organizations can also negotiate for eminent domain purchases. This was essential for the recent planning of the MBTA (GLX) project [63, 64]. For greenfield property owned by the state, the transit agencies are often competing with needsof highways and with private developers. As public transportation agencies are looking at projections of urban and demand growth, it would be beneficial to reserve and maintain ownership, of land parcels needed in the distant future, to maintain feasibility and efficiency of the transit system in large cities (to avoid some of the current MBTA challenges from inevitable re-occurrence in the future).

For example in 1947 Boston public transit anticipated future expansion of the Red Line to Lexington. This was abandoned in 1977 after a tremendous opposition from residents of Arlington who tried to pass a state bill banning the rail extension [8]. A shorter extension was completed in 1985 (from Harvard to Alewife). Alewife was intended to serve as a temporary terminus station, until the extension in a later phase would be completed. Today, Alewife station itself causes a transit bottleneck largely due to the lack of terminus facilities [123]. Although MBTA, still owns the ROW needed for the Arlington/Lexington Red line expansion, it is highly unlikely that the expansion will occur, as the route between Arlington and Lexington is now a popular bike (Minuteman bike path [8]) and adjacent properties have been sold to private owners [104]. This example illustrates the importance of separated ROW and land holding for supporting transit expansion needs current and future.

41 2.6 Process of Capital Investment Planning

Large capital investment projects and are generally funded by the state and/or federal government (and revised by associated federal regulation bodies such as FTA ) while infrastructure projects are proposed internally in public agencies the funding of these projects is appropriated from state bud- gets or federal programs. The high cost of these projects creates competition for limited resources. There is a growing focus on political costs associated with project duration and community im- pacts. Similarly, with long development time frames it is challenging to secure political support for transit projects where benefits are revealed many years later. Cost inflation and a long listof projects in the pipeline pose an even larger hurdle for political endorsement. Between 1970 and 2016, the US has steadily decreased its investment in public and transit infrastructures, (as have many European countries [54]). This period of under-investment has left public transit with a long backlog of state of good repair projects and critical service expansion needs [55, 97]. During this period, many structures have deteriorated and now present risks to safety and reliability of services [7] [97]. With the US experiencing several large natural events demonstrating the vul- nerability of coastal cities, there is a growing recognition of the significant role of public mass transit [3, 19, 20, 74]. In Boston, the MBTA system has an accelerated plan for addressing the backlog in its state of good repair projects (with estimates of over $10B in May of 2019, a $3B in- crease from the estimate of 2015 [18] [55]). Meanwhile, delays to the Green Line Extension (GLX) project have increased expected construction costs from $700M to $2.3B. The delay has impacted communities that are under-served by public transit, loss of transit revenue and private property investments. Overcoming the political aspect of public transit infrastructure investment is very challenging and different between each city and agency. The under investment to the highway and public transit infrastructure systems could be and is an easier funding investment to postpone, its results in the long run would be noticed with sudden system failure [22, 45, 76], would cost more, create much larger operation disruption and passenger negative impacts.

42 2.7 Public Opinion and Influence of Social Media

Politicians have the ultimate power on the budget allocation to public transportation agencies for project construction, to maintain safe, comfortable and efficient services 2. Politicians are held accountable by the public through multiple avenues (i.e. elections, opinion polls, protests , media coverage) and the public now has the ability pressure politicians today 24 hours a day using social media. The power of internet connectivity and of social media enforces the public to monitor news of funding decisions, planning processes etc. relating to transportation projects, and to make their opinion known, at times shifting budgets and reversing approved decisions.

This is well illustrated by the decisions concerning the repairs of the MTA L line tunnel con- necting between Manhattan and Brooklyn. The tunnel was severely damaged by hurricane Sandy (2012), while it was awaiting long-delayed structural renovations [49]. Immediate repairs were done to restore operation on the line, but extensive structural repairs were needed to ensure safety of the infrastructures. The L line is a heavily used line connecting Brooklyn and Manhattan 3 with week- day daily ridership of 400,00 and 225,000 passengers along the damaged tunnel segment, that is not serviced by any other means of public transportation. After an internal planning process, MTA announced an expected closure of the L line of 18 months, to conduct full tunnel renovations [116]. The chosen solution not only shut down the L-train, it also proposed very poor alternative services to passengers. The project was re-envisioned and approved by MTA with an expected closure of 15 months [76]. Publication of the project construction and passenger mitigation plans were again heavily criticized by the public on social media [56], that portrayed grave predictions for the com- muting congestion consequences on other 14 lines during the duration of construction [119] [26]. The governor of state intervened and set up an independent panel of engineering experts (from Columbia and Cornell Universities) to assess better construction staging alternative as the start date for construction was fast approaching [117]. The panel proposed a much less intrusive methodology [21], reducing impact on train operations (weekend shutdowns only). The impact of the public and media engagement and opposition to this project led the MTA to go back and

2it has been shown previously, that when the area covered by public transportation is low, its connectivity, its bounded coverage will create very local and low passenger demand for the service. This creates the cyclic process of low investment or incentive of investment into public transportation improvement and feeds the continuation of low demand. 3The L line tunnel is a 100 years old

43 refine an already designed construction project that was relatively intrusive and disruptive tothe public. This process illustrates that engineers/planners need to be engaged with the community in their approaches and methods.

44 Figure 2-1: Mode distribution of commuting patterns in Boston developed for Go Boston 2030 transportation plan (Go Boston 2030, [78])

45 Figure 2-2: Schematics of dynamic envelope of a tunnel (Railsystems.net 2019)

46 47

Figure 2-3: Map of Cambridge, MA composite natural hazard impact map (Cambridge.gov, 2015) 48

Figure 2-4: Full alignment of proposed changes to the I93 and parallel MBTA right of way discussed in this project [38] 49

Figure 2-5: view of Savin Hill station area of the proposed new highway and rail alignments (study to expand Southeastexpressway, 2012 [38]) Table 2.1: MBTA four rail operation dimension requirements

Network name Platform height [inch] Operating power Width [inch] Length [ft]

Red Line 49 120 69.5 Orange Line 45 Third rail 111 65 Over head catenary Blue Line 41.5 111 48 and Third rail Green Line Low Over head catenary 104 72

Current fleets dimensions, though for all lines those are prescribed from tunnel dynamic envelope and other historical constraints

50 Chapter 3

MBTA, Past Present and Future

The MBTA provides public transportation services to over 175 cities and towns in Massachusetts and covers 5 different modes of transportation. Although it was only created in 1963, the first public started in 1631 and surprisingly much of the current right-of-way and routes owned by the MBTA were built long ago and inherited from multiple private transportation companies [92, 103]. This chapter focuses on MBTA rail transportation modes which includes; light rail Mattapan and Green line trolley services; heavy rail routes (Red, Blue and Orange lines), and the Commuter rail services originated from North and South stations with 13 service routes (some lines have branches within the route). This chapter will summarizes the history of Greater Boston and MBTA, the current transit and commuter rail networks, with a more in depth view of Red Line and South Boston rail corridor empathize that are presented in chapters 4 and 5. The chapter also looks at the projection of future states of the MBTA rail system based on current and long-term projections.

3.1 Creation of a Transportation Hub, Boston

The first mode of mass, shared transportation in North America started in Boston with acharter ferry route from Boston to Charlestown in 1631 [103]. Harvard University ran this service from 1640 to 1785. The water mode of transit was not sufficient, as settlements grew outside of the city, and their was demand for faster mainland transportation solutions. One of the first bridges across the Charles river (Charles River bridge, connecting Cambridge to the North End) was opened in

51 1785 with private funds supported by tolls [110].

The first railroad in America was established in 1826 in Quincy, by the company and designed by the engineer Gridley Bryant. This private company actually operated a three mile route between the Quincy quarries and the . Figure 3-1 shows the overview of Granite railroad alignment, together with more details of the adjacent properties. Today most of this historic right of way is part of the Southeast Expressway road (I-93) and the Old Colony Commuter rail line. In the 19th century, it allowed for the first actual mass transit commute to the Boston area [92,100]. From 1830 a growing number of routes were approved for steam locomotive trains in the state of Massachusetts, beginning with the route from Boston to Lowell (opened in 1835). From that point forward, the greater Boston had almost 100 years of railroad route expansion, making a peak in active Commuter rail routes in 1929, connecting the city of Boston with communities beyond a 10 mile radius (i.e., outside zone A1 of the current MBTA map, shown in Figure 3-12 ). Most of these routes were built and operated by private companies, with charter authorization to supply public commuting services.

Figure 3-2 shows an 1871 map of Massachusetts together with a list of the operating rail compa- nies. The rail alignments are marked in black thin lines, many of these rail corridors are still being used today. Figure 3-3 shows the expanded state of electric railway map across Massachusetts from 1905, marked in orange are the towns served by electric street railways within the state and in red lines the alignments of commuter rail steam railroads. Figure 3-4 shows the decline in railroad operations between 1934 and 1984, highlighting the deactivated railway rights of way. Figure 3-5 compares current freight and passenger operations for all tracks in Massachusetts (including the ROW and operations of the MBTA commuter rail); Although the amount of active rail is lower today than the peak of operations in the 1930’s, it is also noticeable that ROW activation and deactivation has occurred quite frequently over the years. The constant change in service routes, frequency, prices and even operators was the key driver for the state to create a single organization, to subsidize the costs and create stability for public transportation services within Greater Boston.

The chartered companies providing Commuter rail connected in Boston at two termini; North Station (opened 1893) the terminus station for all trains coming from north of the Charles River, and South station (opened at 1900) the terminus station for all trains coming from south of the river. These two stations connect to the urban rapid transit system within Boston, but travel

52 between the two stations requires a transfer with no direct rail link and creates a large gap in the regional rail system. The two main train stations have never been connected although this has been the subject of discussion since it was first proposed in 1910 [40]. Figure 3-6 shows a 1914 plan with a proposed below-grade rail connection between North and South stations. The legislators plan was to purchase the properties along the alignment, that was already fully urbanized in the early 20th century, and close that portion of central Boston during construction. The project was shelved for a later time due to complexity and the challenge of a state funding for a project that would benefit private rail companies [40]. Population and economic growth in the stateof Massachusetts and dependence of the economy of the commercial business districts on heavy use of transit lines, combined with abundance of private stakeholders, have added much larger challenges on the complexity of design and construction process for the North-South rail link project over time.

The system within Greater Boston, can trace its roots to the first underground section of the Green line, opened in 1897. The project was designed to address the congestion of the surface streets (Tremont, Park, Boylston, Pleasant etc.). Along the new tunneled alignment operated by the , all the elevated street car network in Boston and its inner suburbs spread rapidly and was operated by a single company, BERy. The rapid transit networks in Boston were also leased by BERy from their different private owners, in a first attempt to unify rail operations and improve passenger quality of service. By 1925 the system reached its peak size, and some of the street car operations transitioned to bus services [35]. Figure 3-7 shows Greater Boston in 1925, with marked BERy supplied operations, of all types ( LRT, bus, rapid transit and street cars). Most of the early 20th century lines, condensed into the current Red, Orange, Blue and Green line of the MBTA, while other were deactivated and abandoned (such as the tunnel under City Hall Plaza [17]), transitioned into the Mattapan line or Commuter rail, or became service tunnels for the system [92]. In 1919 Massachusetts passed a law protecting BERy passenger while providing the company with a financial safety net from losses and closure. However by 1947 the advantage of a single private transit operator was reversed by a plunge in ridership and the growing need for state financing. The first iteration of a public transit agency, MTA (Metropolitan Transit Authority) was formed by absorbing BERy, in 1947. Figure 3-8 shows the rapid transit systems operated by MTA from 1947. The MTA expanded beyond BERy serving 14 cities and towns when formed [92].

53 The 1950’s and early 1960’s created severe financial pressure for the commuter rail companies, after a big commute mode shift to private cars [103]. Several commuter rail lines were abandoned by their respective companies, and prices for service increased and changed constantly. The State also saw a growing problem of congestion in the greater Boston area and the need for cheap mass commuting services. As the MTA could not legally or operationally absorb the private Commuter rail assets, the Commonwealth created a new and improved public agency that would be responsible of the lines/branches and the prices of the Greater Boston and Boston’s public transportation system [51,103].

3.2 MBTA Current Operations

The Massachusetts Bay Transportation Authority (MBTA) was created in 1964 as a state agency to manage and operate all of the large, shared modes of transportation of Greater Boston. Most importantly, to regulate the prices and provide stability for transit operations. The agency ab- sorbed the MTA and expanded the mass transit services from 78 cities and towns when it was formed to over 175 cities in Massachusetts and neighboring states today. Most of the early growth of the MBTA was done by acquiring, one-by-one, all the private rail companies and bus companies that operated in its outreach areas [51, 92, 103]. But in the 1970’s, along with a large amount of highway projects were built, the MBTA received funds to expand its rail and bus services. Most of the rail corridor the MBTA operates to this day within Boston and its immediate neighboring towns is comprised of pieces of track and property previously owned by private companies it suc- ceeded, i.e the MBTA inherited much of its rail corridors, facilities, assets and right of way, and was never designed as an integral system.

Today, MBTA is one of the divisions within the Massachusetts Department of Transportation (MassDOT), and is one of only two US mass public transportation systems offering 5 different modes of transportation; bus, ferry , heavy rail, light rail and commuter rail. Figure 3-9 shows the current full rail network operated by MBTA, in the bottom left corner we see a larger scale view of the transit in Boston and its immediate suburbs. Figure 3-10 shows the same Boston rail transit on an MBTA schematics map. The Orange line operates between Roxbury and Malden; the Blue line runs from Revere to Boston and the Red line operates from Alewife to either Ashmont or Braintree. The Green line has four branches coming from Downtown Boston and diverging

54 into the suburbs of Boston. The terminus stations of the branches B,C,D and E are at , , Riverside and Heath street, respectively. The MBTA operates 149 light and heavy rail stations, of which less than 30 are underground, most of them are in center Boston and Cambridge (the Red line). Figure 3-11 shows the a map with all the rail links separtaed by the year they were built. Downtown Boston, a dense business district, is seen in larger scale on the left side of the figure, all rail stations there are below ground, with the latest rail link builtin 1917. We can see on the map the density of stations and the earlier construction year in downtown Boston, and the late 20th century alignments as the rail reaches further outside the city.

3.2.1 Commuter rail network

The Commuter rail network, is a heavy rail system connecting Boston to the region, providing short distance, city to city rail operations, currently carrying 125,000 commuters weekdays [81,91] , with over 130 stations in Massachusetts and . Figure 3-9 shows the area connectivity of the current Commuter rail lines, including the lines used as secondary (to ) and future service expected for the South Coast Rail (extending service to Fall River and New Bedford). Figure 3-12 shows the same commuter rail network outreach on the MBTA’s current zoning and cost map. Today there are 12 commuter rail lines operated by supplying the services for the MBTA. Five of the lines operate from North station , while the other 7 operate from South station, some of the Commuter rail lines are branched lines, operating on a shared right-of-way. As the Commuter rail system is predicted to grow in demand in the next years, and also serves Freight and trains. Many services are at capacity and and are limited by frequency of services (adding cars to trains), and will require double tracking to improve services. The benefit of passengers of the 4th most used Commuter rail network in the US, will be a much more reliable service, better frequency and capacity [106] [120].

3.3 MBTA’s Near Future

With the start of a new decade in 2020, the MBTA infrastructures throughout the system are in urgent need of renovation [18, 55], expansions are needed to support communities undeserved [27, 98], to improve the quality, capacity, reliability [4, 22] and safety [69] of services. Considering

55 each of these deficiencies there is also a need for a mitigation plan to reduce impacts oftheir inter-connectivity [27, 53] (i.e., impacts of aging infrastructure, risks of rail incidents, safety of passenger services). The needed relief for greater Boston’s current and future road congestion [50] and transit daily peak hours should be always considered deeply while identifying, designing and staging projects. Both the projects outcome improvement after construction and the disruptions during construction period should dictate a plan of action. The current state of many of the lines within the system are at capacity creating higher infrastructure deterioration and associated safety and reliability risks, with a large list of currently approved projects for CIP five year [89] and 2040 vision [72] plans, and very low execution feasibility for an array of different reasons. The gap between project approval and its existence in the capital investment plan for many years without being built, presents a major challenge for maintaining operations.

There are many projects under construction at any given point within the MBTA system. The following paragraphs mention four of the most impactful projects that are currently under con- struction. The GLX, the South Coast Rail, the Regional rail vision and the Red Line 3-minute headway project. All projects comprise multi-phase multi-year projects, and are part of current CIP.

The GLX (Green Line Extension) project is the first local transit new rail expansion since 1985, adding 7 stations to the Green line directly connecting Somerville and Medford to Boston by rail. The project was first announced in 1990, with a full price tag of $200M. After a long delayin execution, a lawsuit was filed against the state for stalling the project, forcing the state toset a date for construction execution [107]. Construction started in 2012, and the final budget of the project reached $2.3B (split between federal, $1B, and state, $1.3B funding), [63], with a full project redesign [64]. Key benefits will be substantially reducing the commuting time to central Boston with no transfers, and reducing road congestion from the North of Boston. Additionally, the new project design incorporates improvements in flooding resilience in Somerville as part of the alignment and stations. Lastly the projection of economic growth due to improved accessibility to commercial business districts in Boston and largely due to investment and development of Somerville and Medford [23,64]. Figure 3-13 shows a map with the GLX alignment and the rest of the current Boston transit, looking on the geometry of the alignment between the existing Red and Orange lines the current gap of accessibility to rail service by Somerville and Medford residents. The GLX is expected to open by 2022 (January 2020 estimates) along with the expansion of the

56 vehicle fleet [11, 63] to maintain the previous frequency of service on the Green line andimprove capacity.

The largest source of growing demand for new MBTA services is on the Commuter rail network, with many communities desiring to expand Commuter rail and have direct services to Boston. The South Coast Rail project, Figures 3-14 and 3-15, is a multi-phase project that would strengthen the regional rail of greater Boston, restoring operations to the southeastern commuter rail corridor that were disconnected in 1959 [44]. SCR will connect the cities of New Bedford and Fall River (with combined population of 250,000) to Boston [66], helping to reduce the severe road congestion commuting to Boston from the South. The economic regional benefits by providing easy access to commercial business districts in Boston and growing job hubs in the suburbs of the city, affordable housing, and boosting the development and economic investment in Fall River and New Bedford communities [67]. The assessment of the project was made in 1995, while the state allocated $136M for the project the following year, the 1997 alternative design had a almost a triple price than available state funding [77]. From that moment, the project execution time-line has been moved several times, each time creating a redesign and reassessment of costs, until the approved redesign from 2017 [44] and funds allocation for phase 1 in 2019 [58]. The current full cost evaluation for this project for both phases is $3.4B and is expected to be completed by 2030 [66]. Construction on phase 1 of the project started in July 2019, with a federal funding of $1B for the first phase, that includes restoring a link of deactivated rail corridor and building six new stations, as shown Figure 3-14.

Phase 1 will provide services to half of the final SCR project rail stations (including the two large towns) by 2023. Providing 7 years of services along the South Boston Old Colony rail corridor, while the final alignment will be under construction. Figure 3-15 is showing the final alignment of the South Coast Rail project, adding additional five stations and building a new rail corridor between Stoughton and East Taunton [66].

Other regional rail operations have been considered in 2018-2019, Rail Vision [72, 121] that developed six alternatives for regional rail growth and service optimization. The analysis assessed higher frequencies, better alignment configuration, vehicle power source, expansion projects, and even assessing the service model provided by the agency and its efficiency compared to other large cities [105]. The Rail Vision project incorporates both the needs and constraints of the regional

57 rail transit and combines multiple rail changes within each of the final alternatives to improve the Commuter rail from a low frequency service into an efficient high frequency regional rail network.

Figure 3-16 shows Alternative 6 for the regional rail presented to the MBTA board, as an ex- ample to the proposed changes. This Alternative implements full network transformation to rail electrification (to improve train running times) and completion of all major structural projects within it (i.e. building the North-South Rail link and South station expansion) [72]. No single alternative was chosen by the board of MBTA. In order to optimize the costs, environmental benefits and passenger demand, the committee was asked to refine its suggested alternatives with a clear lean towards the electrification of rail for environmental and operational costs along the network [60,72]. The potential regional impact of this project could be enormous, on the environ- mental, road congestion, population and suburb growth as well as the economic boost after transit service improvement projects. The research and analysis done to plan the 2040 optimized regional plan is allowing to capture many of the regional challenges, balances and needs to improve the system as a full unit rather than create local constructions and repairs [121] [105].

For the Red Line, the current project aims to improve service frequency to a 3 minute headway (50% improvement compared to current rush hour 4.5 minute frequency). Within the bounds of this project the MBTA is replacing the signaling system along the alignment and purchasing a new fleet of vehicles [10] replacing the outdated rolling stock and expanding the fleet sizeby252 cars. The project includes also expansion of of storage and maintenance facilities (Cabot Yard, Codman Yard) to accommodate the new fleet [94]. The main problem with the MBTA Redline project is the lack of broader view to the system abilities, and its structural and transportation bottlenecks. The state of good repair needs along any of the MBTA rail lines is impacting the headway of the fleet, and mostly the headway variability between trains causing reliability issues. The current CIP [89] for the Red Line, mostly invests in fleet infrastructure, and the signaling system. It does not consider structural bottlenecks associated with train storage, track alignment and low speed blocks (due to safety/noise/infrastructure issues). These structural impacts create transportation bottlenecks are likely to prevent the Red Line from achieving the 3 minute headway if not prevented, as discussed in chapter 4.

58 59

Figure 3-1: Alignment and layout of the railway in Quincy, 1826 (Library of Congress) 60

Figure 3-2: 1871 map of Massachusetts, showing the active Rights of Way of different rail companies (Walling and Grey 1871) Figure 3-3: 1905 Map of Massachusetts state showing the rail road marked and the cities with electric street car services. (Wilkie and Tager, 1991)

Figure 3-4: 1984 Map of Massachusetts state showing the decline in railroad in the state from 1934 to 1984. (Wilkie and Tager, 1991)

61 Figure 3-5: Current map of Massachusetts rail operations, showing MBTA commuter rail, AM- TRAK and other ail active alignments

Figure 3-6: Map showing Boston center, with the alignment connecting North station to South station, from October of 1914 (Boston Public Library)

62 Figure 3-7: 1925 map of Boston center, showing transportation system network operated by BERy (Boston Public Library)

63 Figure 3-8: 1947 map of rail transit services provided by the MTA in Boston and adjacent com- munities (Massachusetts Department of Transportation library)

Figure 3-9: Current map of Massachusetts commuter rail network, the seasonal rail lines and the South Coast Rail Southern Massachusetts expansion project.

64 Figure 3-10: The transit map of Boston, shows the Red, Green, Blue and Orange lines, as well as other rail and special bus services (silver line) provided by the MBTA (MBTA website, 2020)

65 Figure 3-11: MBTA Boston rail transit network dividing by different colors rail links in Boston by the year of their construction

66 Figure 3-12: Map of the current Commuter rail network and zoning. (MBTA website, 2020)

67 Figure 3-13: A map of the immediate communities west of Boston, showing the new green line extension and the new 7 stations in a thicker green line, and all the current rail operations marked by their respective line color (Mass.gov 2020)

68 Figure 3-14: Map showing the current commuter rail south of Boston and phase 1 addition of the South Coast Rail project. The rail link between Middleborough and East Traunton is a temporary alignment reactivating an existing abandoned rail corridor. (Mass.gov, 2020)

69 Figure 3-15: Final alignment of the South coast Rail, showing the final alignment of the South Coast Rail . (Mass.gov, 2020)

70 Figure 3-16: Example of Vision Rail project alternatives for 2040 regional rail. The shown alter- native, is alternative 6, the most expensive alternative, adopting a full rail electrification and most of the individual construction and investment projects (i.e Nosth South rail link, fleet expansion, full network accessibility etc.) (MBTA website, 2020)

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72 Chapter 4

Analysis of Physical Bottlenecks for Red Line

4.1 Introduction

The vehicle capacity of a rail line usually refers to the maximum number train units that can traverse the route per hour 1. This capacity is often limited by bottlenecks along the system associated with the dwell times in stations, speed, signaling system etc. Rail line capacity is directly linked to rail speed codes, reliability (incidents, delays etc.) and quality of service (passenger loads on trains, left behind at stations etc.) [102]. Bottlenecks usually occur during periods of high frequency service (peak hours) at the same locations along the alignment and corresponding to locations with the lowest capacity. During these periods if the scheduled frequency is higher than a link can sustain, service will deteriorate, and a queue of trains will occur [102]. The causation of the bottlenecks usually relates to: 1) the vehicle fleet; 2) the signaling system; and 3) track alignment and configurations. The size of the vehicle fleet and supporting infrastructures impact the quality of service, operational reliability, and safety of the system. Operations in many older transit systems have constraints associated with track layout, curvature, and dynamic envelope of tunnels. This chapter considers how physical bottlenecks affect current operations and future service plans for the Red Line.

1Capacity, C=Δ⃗ t/H, Δ⃗ t is the unit time period (typically hour) and H is the headway (normally in minutes), for the Red Line C=13-14 trains/hour, H=4.5 minutes (for the merged tracks of the branches [85])

73 Over the next few years the Red Line will introduce an update to its signaling system and a new vehicle fleet, to improve its rail service (frequency, passenger capacity and service performance). Changes to both of these systems will also reduce their impact on existing bottlenecks. For example, the introduction of the new signaling system will allow improvements to the scheduled headway associated with change in train speed codes. The current system uses 3 speed codes ( 0 mph; 10/15 mph; and 25 mph) while the new system will have 7 speed codes (allowing for higher train speed for many of the alignment segments). However, once the new fleet and updated signaling system are in service, bottlenecks will continue to occur. These are dynamic in time but not in space, reflecting an intrinsic limitation in the physical infrastructures. Figure 4-1 characterizes the structural causes of bottlenecks in three categories: 1) alignment deficiencies; 2)inadequate infrastructures; and 3) degraded infrastructures. Structural degradation and changes in scheduling only assist to the creation of new bottlenecks. This chapter focuses on the structural aspect contributing to the creation of transit bottlenecks for the Red Line, diagnosing their impacts and proposing potential potential mitigation strategies (for the long term).

4.1.1 Alignment deficiencies

Geometric design is a major factor controlling design speed and reflects to previous legacy of construction, creating a unique problem for operations along routes that would have not be in compliance with today’s design constraints and requirements. For example, Figures 4-3, 4-2, 4-4 show calculations for horizontal rail alignment curvature used to specify the speed code for the MBTA’s Commuter rail lines [86].

√︂ 퐸푎 + 퐸푢 푉 = 0.0007퐷 50 푠푖푛(퐷/2) = 푅 푒 = 퐸푎 + 퐸푢

For the Red, Blue and Orange lines e=4.011푉 2/R [87]. where V [mph] is the velocity, D is the ; R [ft] is the radius, e is the equilibrium elevation (i.e. the elevation needed

74 for a curve with a certain velocity to be at equilibrium with the angular acceleration overturning forces), Ea [inch] is the actual superelevation, and Eu [inch] is the unbalanced elevation.

Table 4.1 shows train speed restrictions for designed degree of horizontal curvature Commuter rail alignment configuration requirements [86]. Currently Commuter rail has a maximum allowed actual elevation Ea=6", and an Eu= 1.5"-1.75", while for the Red Line Ea=6.5" and Eu=3". Similarly, the vertical alignment, allows maximum grades of 0.7% - 1.5% for the Commuter rail [86] and up to 4% for Red Line [10], (steeper grades are allowable with special approval and/or reduced speed). The vertical curvature, seen in Figure 4-5 is restricted to a minimal length of curve and grade difference to ensure safety for "accordion effect" associated with train units comprising multiple joined cars. The contributing effect of the horizontal and vertical curvature arises both are close to maximum allowable values. Their impact on each other is not addressed with specific calculation, but instead is handled by a reduced speed code. Problematic links allowing the route alignment with such combined vertical and horizontal geometric restrictions are likely to be (or to become) critical structural bottlenecks with accelerated degradation.

When considering much of the bounded existing alignment of the MBTA urban rail network, the degree of curvature dictates the allowed velocity (and impact of deceleration/acceleration patterns for restricted speed segments), creating signal blocks with a reduced speed code, and potential bottlenecks at peak hour. A clear example is the the approach to Boylston station on the Green Line, Figure 4-6. The original station plans from 1898 and the current alignment in Figure 4-7, having a very sharp curvature, the passage of trains at that curve is at a near zero velocity (with a very heavy screeching noise from the wheels). There have been many years of complaints from passengers [47], while high wear and tear requires frequent maintenance for the tracks at that portion of alignment.

The current width clearance of some existing old tunnel infrastructures also do not comply with the comfortable passage of the allowed speed for the geometry at those segments (i.e. the horizontal space between wall and trains is too small for horizontal movements of the train), creating a reduced speed code. Another problem arising from the structural deficiencies is that the actual speeds (and high impact of acceleration/deceleration patterns) vary widely between the individual drivers (i.e. high variability in actual vs allowable train speed). This variability impacts the actual headway between tracks, contributing to operational reliability problems and creation of bottlenecks along

75 the rail line [102].

Geometry constraints also impact the wear and tear at critical sections of tracks, creating the need for frequent maintenance work (and higher costs) and risks of incidents that disrupt operations on already more constrained segments of the line [5, 52]. An extensive study into the breakdown of maintenance costs in high speed rail networks in Europe found that the largest impact on track degradation and maintenance frequency is from the geometric layout/alignment and vertical and horizontal curvature [12]. Those factors actually impact rail maintenance substantially more than the track structure (i.e rails ties, sleepers etc.) and their supporting substructure (ballast, subgrade, concrete slabs etc.).

For example on the Red Line there is an at grade cross-over at the approach to Alewife station, that causes two simultaneous problems: 1) the geometry affects the variability of passage times for trains departing the station [123]; and 2) the curvature of the tunnel has created a maintenance hot spot with a reduced speed code (to prevent derailment and mitigate track degradation) [68]. This cross-over is discussed further in section 4.3.

In dense urban rail transit networks, speed restrictions/limits may be due to proximity between stations and the use of fixed block signaling system [102]. This is very familiar in cities suchas London and Boston arising from a historic legacy of developments, and creating situations where surface 2 routes between stations are faster than tunneled route. The acceleration and deceleration process entering and exiting stations are large component of station dwell time, considering that signaling blocks are at least a train length. For small station spacing, trains may not reach higher allowable speeds (25 mph or even 10/15 mph between stations. In most modern urban rail systems there is a minimal spacing between stations, typically 3,250 ft. (at least a 1000 m) to ensure optimal service, operations and coverage for the passengers [102]. Inefficiencies arise due to close proximity and are inevitable a source of bottlenecks. When proximity between stations is small, train speed is reduced ( or stopped) and delays are accumulated at successive stations. One example of this historic deficiency occurs on the Red Line where Park Street and Downtown Crossing stations are located approximately 565 ft. apart (i.e. less than single six car train set). When one station is occupied the other has to remain empty for safety reasons, contributing to dwell time [123].

2In London, the Tube map indicates inter-connections where a walking route is faster than train travel

76 4.1.2 Degraded infrastructures

The performance and stability of infrastructures vary over their design life (from good state with small maintenance needs to deficient structures requiring speed restrictions). A rail line comprises many components and facilities (including permanent way, junctions, bridges, supporting facilities and station infrastructures) with a distribution of states and maintenance needs at different stages of their design life and structural state. Hastak and Baim [30] show how such features associated with asset management and maintenance vary with life cycle 3, and the consequences on transit operations and costs. The consequences could be much more disruptive than previously considered with higher costs, and service disruption for structural repairs [5, 31]. The deterioration of one infrastructure system within the rail line network impacts other adjacent infrastructures around it, amplifying the total network deterioration rate, increasing risk of disruptive and very costly incidents across the rail network.

4.1.3 Maintenance frequency

Regular maintenance of rail permanent way and supporting infrastructures requires a sophisticated methodology of asset management to ensure the safety and reliability of a wide range of track structure components (i.e. ballast, rail, switches, crossings etc) to stations (i.e. platforms, control rooms, supporting station facilities etc), bridges, tunnels signaling system, power systems etc [12]. The frequency of regular maintenance for systems with unfavorable geometry is much higher in order to remain in compliance with current alignment design guidelines. When degradation is high, additional speed restrictions are applied to ensure safety (these could be on top of restrictions due to unfavorable geometric alignment), and help create more bottlenecks in the network. The MBTA maintenance practice sets thresholds and inspection guidelines [87], for all of its heavy rail tracks, to mitigate deficiencies (and higher probability of failure) at maintenance hot-spots. For example, taken from the code in Figure 4-8 shows the operational speed reduction and required maintenance once a rail track is degraded. For the Red Line, the sharp turn on both approaches to Harvard Square station and the crossover approaching Alewife station have additional speed reductions and

3Structural life cycle is the the time span from the moment the structure is under design, to its construction, to its operation and maintenance time until its renovated fully or dismantled. [29]

77 require frequent maintenance.

The MBTA has a large backlog of deferred maintenance due to under funding over an extended period of time. As a result, the rail system relies on structures that are at higher risks of failure, making the network more vulnerable to disruption. In practice all renovation projects (requiring capital investment) involve a process of design and planning (including construction sequencing) and impact assessments on operation and overcrowding. Many larger projects are also subjected to public review processes, complete budget is allocated yearly based on the rolling five-year capital investment plan (CIP). Funds are allocated from different departments for separate projects (i.e. maintenance, CIP, operations etc.), at times involving construction in the same general location but causing additional disruption (separate project time frames). The planned queue for project execution may be easily delayed when a malfunction event (e.g. unexpected closures of parking garages due to structural deficiencies, tunnel flooding, damage caused by derailments etc) causing immediate re-allocation of any available funds for emergency repairs (i.e. for a system already having strained funds, release of money for immediate repairs would delay the queue of designed projects for CIP or renovations deemed less urgent).

For example, damage to rail-side signaling infrastructure caused by a Red Line train derailment in June 2019 caused 20-40 minute delays in rail services for the whole line over a period of 3 months [4, 22]. This single failure reportedly cost $200M to repair (a new signaling system was scheduled to be constructed starting in 2020, to replace the repaired system).

Following the high incidence rate in recent years [45], the MBTA convened an independent Safety Review Panel of experts (SRP) to review the agencies policies, procedures and practices to improve the agency for passengers [69]. The SRP report found deficiencies within the agency in many of its departments and organizational structure (such as the leadership, management prac- tices, engineering design practices etc.). Two key safety deficiencies were the lack of Preventative Maintenance and Inspections (PMI) and structural quality control for the system (with severe lack of documentation for existing infrastructures) [69]. The SRP expressed its concerns about the current state of the MBTA and acknowledged the need to expedite project executions to close the alarming gap in structural safety and PMI. The report emphasizes the importance of state of good repair practices while maintaining everyday high quality of operations, and the need for new strategy to deal with these issues [69].

78 4.2 Bottlenecks on the Red Line

4.2.1 Alewife

The Alewife terminus station is a grade-separated multi-modal transit station, with the under- ground Red Line and a street-level , Figure 4-9, 4-11. In 1977, while the Harvard - Alewife extension was under construction, the planned extension to Arlington and Lexington was canceled. In 1991, the ground was converted into a bike path (the ), with the ROW still technically owned by the MBTA, but with no option to restore services along the ROW. In the current era, the feasibility of re-using the 1947 alignment is highly unlikely, as the right of way is occupied and commuter rail facilities abandoned in 1981 (after closing commuter line passing through Lexington to Boston in anticipation for alternative rail service in the future) [96].

A 1985 study conducted for MBTA considered design alternatives for the abandoned ROW, and the alternatives for the future service mode to be provided for passengers [8]. The report chose the Minuteman bike path along with Bus services from Alewife along a parallel route to the tracks. This solution reduced construction costs compared to recovering rail operations and expanding them, but in the long run this solution added vehicles on the road leading directly to Alewife, and never addressed the change of Alewife station purpose and its supporting facilities.

Alewife was opened in March 1985, and was considered a temporary terminus for the extended Red Line. The original project was supported by industrial and residential growth in West Cam- bridge. Alewife was designed as intermediate station for further extension of the Red line to Arlington and Lexington. The original design anticipated the high use of station facilities in Arlington and Lexington that would mitigate congestion associated with commuter traffic.

The terminus station (Figures 4-11 - 4-12), comprises of a single island platform between two tracks that extend behind the station (where up to 6 train units can be stored), Figure 4-10. There is a crossover located at the approach to the station to enable each platform to serve incoming and departing trains. According to the TCQSM (Transit Capacity and Quality of Service Manual 2013 [102]) Alewife station facility configuration (i.e. platform and crossover in Figure

79 4-13), are unfavorable for achieving smaller headways. This problem is amplified by the limited capacity to store trains behind the platform or to turn-around the trains at the terminus. Wolofsky (2019) [123] found that during peak hours it is difficult to sustain 4.5 min headway at Alewife station (based on automatically recorded GPS data), and the station is a transportation bottleneck for current operations. Most of the factors causing bottlenecks at Alewife can be attributed to structural components, Wolofsky [123] found only partial mitigation options analyzing and surveying operational processes (drop-back/fall-back of drivers). A long-term bottleneck solution to improve headways at Alewife would have to include expansion of the existing facilities.

The Alewife station area is one of the most congested locations in Massachusetts 4, as corresponds to the merge between Route 2 (built in 1970) and Alewife Brook Parkway. A large portion of the congestion relates to vehicles originating from or approaching the parking garage located above the station [32, 95]. In recent years, the Alewife garage has been at maximum car occupancy for most of the day and now constrains the ability of passengers to park and ride the Red Line [16]. Another major concern regarding the garage is its acute structural deterioration, with multiple reports of concrete spalling on the cars, leading to partial closures for immediate repairs and plans for closure to conduct full renovations [113, 114, 122]. Figures 4-15 a,b show some of the problems affecting the garage structure. As the garage is located above the station itself,and both comprise a single structure, it is clear that any improvement project for the station should also address renovation/repair of the whole garage structure. There is a clear need for expanded capacity to accommodate the parking demand, and to find solutions to mitigate traffic congestion. The existing garage was designed to accommodate 7 floors of parking (instead of the existing 5 floors). At its current state of structural elements, and considering the structure would haveto meet current structural codes that are more rigorous than those planned by in 1980 when the design was approved. It would be beneficial and would reduce congestion by expanding parking capacity through a separate garage solution.

The Alewife station is built within the floodplain of the Alewife Brook (which flows intothe ) and is susceptible to flooding after events of heavy precipitation (storm events with 5-10 year recurrence). The Cambridge multi-hazard mitigation program [79], found the area of the station, and the underground station itself, at a high risk of severe damage from flood events (Figure

4In a recent congestion report made by Massachusetts about congestion in the state [95], found that Alewife (Figure 4-14) is the second most congested area. Roads surrounding Alewife station are congested for over 10 hours a day, and a travel time increased by over 50% for inbound and outbound vehicles between 2013 and 2019.

80 2-3). Analyzing the combined impact of precipitation (Alewife Brook flooding) and back-flow from the Mystic river (due to storm surge) in on the station area, severe storm events pose a very serious risk to the station (while is likely to increase with climate change [79]). The multi-hazard mitigation program is reevaluated every five years, with a proposed mitigation project list. The 2015 edition, while addressing flooding in the Alewife area, did not include estimates for damages or repair costs for Alewife station and supporting facilities. Any project to improve the station, garage or any other supporting infrastructures should include hazard mitigation for the station. The Alewife area is a residential area (but previously was an area of industrial factories) is also known by chemically aggressive ground water causing fast deterioration of subsurface structures (concrete and steel). The tunnels north of Alewife, from the end of the line to the crossover before the station have experienced relatively high seepage and show severe sign of concrete degradation, that require careful maintenance. Figure 4-16 show some of the damages captured in the tunnels behind Alewife station. The tunnels need complete renovation/repairs to ensure safety and reduce risks of failure. For example heavy seepage could affect the third rail system, as happened before during winter of 2015 [41, 43] and shut down the full system, a flooding event could propagate within the tunnels, as the tunnel elevation at the station and the tunnels leading to it is the same, this event would also lead to an extended shut down of the station.

4.2.1.1 Proposed solutions to improve Alewife station

One possible solution for the Red Line terminus at Alewife seems very clear, expanding the station train storage capacities and/or adding a third platform to the station. Currently the station is able to store only 6 trains (utilizing all of its storage capacity behind the station). Improved train storage capacity is needed to be able to dispatch trains more frequently during peak hours (to support the incoming trains) and meet planned 3 min headway. Any project to expand station facilities would benefit from a holistic project design that tackles the whole combination of structural deficiencies, flooding resilience, traffic congestion while focusing on the task of reducing headways thatcanbe sustained during peak hour operations. This task will require expanding and waterproofing the station, strengthening existing facilities, and bringing all tunnels and station storage, crossover, and garage structure to a state of good repair. A single integrated project would optimize time, costs and efficiency but presents a huge construction challenge given the current levels of congestion and

81 passenger demand. Temporary access to Russell Field (located before the station), or Thorndike Field (located behind the station) could serve as potential locations for constructions access and locations for expanding of the underground station facilities to better serve as terminus for the Red Line.

4.2.2 Southern branch terminus stations

The Ashmont and Braintree branch terminus stations, do not have substantial storage facilities for the Red Line fleet (as would be optimal for operational and maintenance efficiency), butdo have the capacity to sustain the current peak headway. Though storage capacity at the branch terminus is similar to Alewife (Codman Yard at Ashmont has a larger capacity), with the train frequency split between the branches, the dispatch frequency currently at peak hours is every 9 minutes. Neither of the branch Red Line terminus stations is a bottleneck to the network under current operational needs and passenger demand. Ashmont branch trains can turn around at Codman Yard freeing the platform for consecutive trains, while at the Braintree station the train that occupies the platform until it is dispatched back (and must wait for the driver to walk from one end to the other).

Braintree is an open at grade station, which serves as a terminus for the Red Line and also a separate stop for the Commuter rail Old Colony line (to Middleborough/Plymouth). The current configuration comprises of an island platform (between inbound and outbound Red Line tracks). The station schematics are seen in Figure 4-17 and Figure 4-18 which show the constraints of near site development.

The Ashmont terminus station is a grade separated multi-modal transportation hub. The station has an outside connection to the Mattapan trolley service and a bus terminus operating at street elevation. Figure 4-19 shows the schematics of Ashmont station, the two platforms in the station, the crossover between them and the continuation to Codman yard. The Red line branch there is underground, with a passage for its tracks ( under the Mattapan service) to Codman yard slightly south of the terminus. The station and its storage facilities are seen in Figure 4-20.

The problem for both terminus stations is when out of service trains get stuck in either terminus station there is limited available storage capacity, and disabled trains must be towed to Cabot

82 Yard, located at the physical center of the Red Line next to South Station. The fleet is stored and maintained only at Cabot Yard, and trains are dispatched from there to all three terminus stations (on the Red Line branch tracks or the merged tunnels to Alewife). With all trains leaving Cabot Yard having to pass through Columbia Junction (a known bottleneck along the Red Line) located near JFK/UMASS station to connect to the track leading to one of the terminus stations. Higher frequency services proposed for the Red Line will require improved terminus facilities to avoid further delays caused by the bottleneck.

The Red Line is changing its entire vehicle fleet, and adding a significant number of new trains in order to increase peak frequency of service. It would be advantageous to create additional maintenance and fleet storage at one of its terminus stations for a more efficient dispatchingof trains to mitigate the bottleneck around Cabot Yard - JFK/UMASS station. Codman Yard (CIP 2020-2024) is scheduled to expand to add capacity for 6 more trains [89], as final fleet numbers are too large for Cabot Yard storage). Cabot Yard itself is currently undergoing a full facility state of good repair upgrades to support better operations, maintenance and improve service reliability. The project also upgrades drainage system (as the area is susceptible to flooding [73]) but is likely to become a more associated project to flooding mitigation [24,71]. The project includes a storage expansion for the expanded Red Line fleet. This would probably not impact the constraint all three terminus stations already pose on the segment between JFK/UMASS - Columbia Junction - Cabot Yard and will only worsen, as trains would still have to night, dispatched and maintained at Cabot.

4.2.2.1 Proposed solutions

The best long term solution for the MBTA would be to move train storage and maintenance facilities away from Cabot Yard south to at least one of the branch termini.

The Ashmont terminus already has a small storage area for trains (Codman Yard), and an unused property around the open facility. Figure 4-21 shows the property boundaries around Codman yard. The property adjacent to the yard is Dorchester Park, which is owned by the city of Boston, is the only property that MBTA could use to expand the footprint of Codman Yard.

In contrast the Braintree terminus station is not as bounded by other transit modes or built properties and is sharing ROW and a station with the Commuter rail, seen in Figure 4-18. Looking

83 south of the station, a large greenfield property owned by the city of Braintree (when borders the MBTA right-of-way) could be the optimal location for a large maintenance and storage facility for the Red Line. The clear benefit of having full fleet storage and maintenance yard facilities ata terminus station for dispatch time, dwell time, maintenance abilities, unnecessary train movement on the tracks. The MBTA would also benefit from being able to use Cabot Yard for other op- erational purposes, as the South Boston area is very dense, and the MBTA property is adjacent to South station one of the two regional rail train terminus that is also pending renovation and expansion project.

4.3 Proximity of Downtown Crossing and Park Street Sta- tions

Park Street and Downtown Crossing are located 565 ft apart (seen in Figure 4-22), such that the two stops cause bunching and headway bottleneck for the Red Line. With the current fixed block signaling system the two stations are separated by only a single track block; with the requirement to keep two empty blocks ( or a two block speed restriction of 0 mph) behind any Red Line train for safety measures. A southbound train can enter Park Street station, only when the proceeding train has cleared the Downtown Crossing station. Figure 4-23 shows the segment block breakdown at the Downtown Boston Red Line station area with the speed code restrictions for the train passage are described under the block schematics. For example a train occupying block 274T (Park Street station) has two blocks with the speed code zero behind it, and the third block is restricted to 10 [mph], line maximum speed is 25 [mph]. The Downtown Crossing, Park Street and South Station stations are the most heavily used along the network. Operating twin platforms at Park Street station (opening both side doors for and alighting, that have to be done manually by the driver) has increasing dwell times as reported by Wolofsky (2019 [123]) Table 4.2 shows dwell times gathered for Red Line stations (NB and SB separated). This data shows only station dwell times that exceed the 3 minutes within a single station signal box, constraining the desired future frequency. For the downtown Boston stations, the data shows that dwell time is already exceeding 3 minutes for each of the two stations, while their small distance poses an even further constraint on achieving a 3 minuted headway. It should be noted, that in current operations, even with

84 the new signaling system added speed codes, unless there is a change in station configuration no changes will occur to this Red Line bottleneck.

4.3.1 Proposed solution

One of the only available solutions to reduce the downtown Red Line bottleneck, would be to consolidate the two stations to operate from a single set of platforms. The station structures are already connected, and a new platform location could be created between the two existing platforms, as seen in Figure 4-24 with the potential location of the platform between the two stations, and accessibility to both existing station entrances (or utilizing one of the two existing stations). The creation of a combined single platform would reduce one of the two largest dwell times along the Red Line (especially at Park Street station boarding/alighting from both train sides); and associated train congestion (bunching stopped trains waiting to enter the stations) improve operations, and potentially enable a 3 minute headway, with minimal costs and operational impacts as all needed facilities and direct tunneled passages between the stations exist.

4.4 Harvard Square Station

The track curvature south of Harvard Square station platforms is a physical bottleneck for the Red Line. The curves approaching the station on both it sides impose speed reductions and create irregular acceleration/deceleration profiles by individual train drivers (due to safety and passenger comfort). The irregular profiles and long dwell times for Harvard square station arealso discussed as a network bottleneck in the transportation portion of the 3 minute headway research, Wolofsky [123] preventing a three minute headway for the line (Table 4.2).

This alignment was identified as problematic during the design of the Red Line extension [1,96]. Figure 4-25 shows the Red Line alignment on a base map of the street overlaying. The tracks were built beneath Massachusetts Avenue and around the edge of Harvard Yard. Harvard University, refused to allow the alignment to pass under historic structures requiring a new unfavorable align- ment [1, 96]. Harvard Square station platforms are grade separated for SB and NB. Approaching and departing trains have a lower speed restriction in the vicinity of the station (reducing speed

85 from 25 mph to 10 mph) along the curves. 5

4.4.1 Proposed solution

The Harvard station train curvature bottleneck is one of the hardest to resolve for the Red line, since the subsurface ROW allowed for the MBTA is greatly dictated by Harvard University and most of the surrounding belongs to the university. There are very limited curvature opening options for the tunnels, and added challenges as the tunnels deepening tunnels north of Harvard Square station (towards station), align- ment overlayed by dense constructed area. Impacting also on construction feasibility and alignment options with current design practices. One long term solution would be re-align tunnels from Trow- bridge street to Waterhouse street (Figure 4-26). This could involve tunneling beneath Auburn and Cambridge common, and under Harvard university property (making proposed solution very challenging to be approved or executed by itself).

4.5 Columbia Junction

Columbia Junction (Figure 4-27) is the largest bottleneck along the Red line (especially affecting Northbound trains operation), and is associated with backups that can extend to the ends of the line. Located directly to the south is JFK/UMASS station. The site is bounded by I-93 (Southeast expressway) and by Commuter rail track to its East. The grade separated, flying junction was opened in 1971 merging the Dorchester line (Ashmont branch) with the newly built (Braintree branch), heading Northwards towards the Andrew tunnel portal, Figure 4-28. The JFK/UMASS station (previously renamed from Columbia station) served as an Ashmont branch station until the opening of the Braintree branch in December 1988. As the station first opened in 1928 [15], and the ROW was active since 1845, it is no wonder that every structural facility of the station (and its surroundings) was created at a different time, and the utilization of the infrastructures is not optimal. (e.g., there is a complete separation of platforms for Commuter rail and Red Lines at JFK/UMASS).

5The headway impact of single operators acceleration/deceleration profiles is studied under a parallel research of the transportation operations simulation tool, Zhou (2020)

86 A significant portion of the NB branch trains arrive at the merger (JFK/UMASS station) out of order, as the Red line operates a 50/50 service split between the two branches, (this results in delays as trains are held at the merger). In current operations, the MBTA never changes the origin station for a driver, such that a train arriving at Alewife from Braintree will only be dispatched back to Braintree. For that reason, it is simpler to hold trains at JFK/UMASS station, until the other branch train catches up and continues along the merged track. Effectively the headway is controlled by timetable. When delays become critical, the MBTA allows out-of-order trains to proceed along the merged tracks, utilizing real time headway coordination to mitigate delays. The operations at Columbia Junction also need to be coordinated with train movements to and from Cabot Yard (to all three termini) adding further overburden to this track segment.

Figure 4-29 shows the variation in headways of the NB trains (from Ashmont and Braintree) over a one month period, Wolofsky (2019 [123]). It should be noted from a transportation opera- tions perspective, headways can be improved by changing the branch dispatching offsets (mitigate some of the out of order arrivals); However, this will not change the large variability in head- way within the branch line trains. Columbia Junction is also a critical area heavily maintained which contributes to the bottleneck creation. As the usage of Columbia junction is very high and will continue to grow according to future demand projections [61]. The tunneled portions have a much lower elevation than the alignment or the surrounding area, and the area is flooded regularly creating problems for the signaling system. Also as it is heavily used, and is more susceptible to infrastructure degradation compared to other parts of the Red Line. Added to that is the curvature for the tracks and the signaling system malfunction and it is well known that Columbia Junction constrains every day operations and is enhance route travel delays.

4.5.1 Proposed solution

Mitigation of the Columbia Junction bottleneck, is not easily addressed, as it reflects problems in train operations as well as physical restrictions and challenges. For the mitigation of the larger bottleneck of the merger, a larger area assessment is needed, as there are several factors that cause the large irregularity in headway for the separate branches. Chapter 5 proposes a solution that involves re-alignment, redesign and optimization of the ROW use, elimination of part of Columbia junction and re-locating the branch merger. For the 1.2 miles between the merger locations, the

87 proposed project will eliminate infrastructure imbalance between the parallel branch tracks to mitigate headway variability along this segment between the branches. Travel times along the Ashmont branch include a stop at Savin Hill station (not served by Braintree branch). Braintree branch has a steeper alignment grade and an almost 0 mph passage speed along Milton Devaughn flyover for safety (while the Ashmont branch remains at grade level).

4.6 Charles/MGH Station

In the dense downtown area of Boston, that attracts large volumes of passengers, there is a clear benefit from direct transfer between the rail lines (improving passenger accessibility andprovid- ing a stronger, more efficient inner-core transit system). The Red and Blue lines are theonly lines without a direct connection, creating a passenger bottleneck (Figure 4-30), which leaves the residents of Cambridge, Dorchester, Quincy, and Braintree without direct connection to Logan , and Blue Line passengers without direct connection to Cambridge.

The need for connecting the two rail lines has been considered for many decades (predating the MBTA). Currently the two lines could not operate on each others tracks due to fleet dimensions. However, historically the lines were to be connected, with the Blue Line terminating 6 in Cambridge next to (current entrance to Kendall/MIT tunnel portal location) and both rail lines sharing the former Eliot Yard (currently ).

A preliminary study from 2010 proposed a configuration where the Blue Line would be extended to terminate below the Red Line at Charles/MGH station (Figure 4-31), the estimated growth in demand for the station was 12,000 daily passengers [59]. The project was shelved due to high cost estimates. A 2018 study concluded the feasibility of construction with an estimated cost of $300M. The study validated the need for the connection and showed much lower costs (than reported in 2010) [65,90].

The Station platforms at Charles / MGH Station, and the viaduct connecting the Station to the Beacon Hill tunnel (to access Park Street Station) are structurally deficient and need to be rebuilt. While Blue to Red Connector is a separate project, its construction needs to be coordinated with re-building of the viaduct, and projects at MGH. The design of the head-house for the Red-Blue

6currently located at Bowdoin, 1500 ft from Charles/MGH Red Line station

88 station, need to be carefully integrated with the Station entry and provide improved access to MGH. Given the extreme lack of space to design these in a compatible manner, and to implement the construction without disrupting ambulance access to MGH , an integrated plan and construction process of these interrelated projects is essential. It is likely that the Red Line will need to be operated as two separate lines, one from Charles/ MGH to the North, and one from Charles/MGH to the South, during part of the station reconstruction. New turn-back switches will need to be located to support the interim operation. There would need to be an interim operating plan, for this very awkward situation in the design (prior to contracting for the construction).

Currently, the Red Blue connector project is in the Focus40 plan again and is approved for further designing without definitive funding sources (and is still associated project execution challenges and limiting constraints). With the general configuration of the Red-Blue connector remaining similar among all solutions, and the feasibility and analysis study still being recent it would be beneficial for the MBTA to try to expedite the process towards constructing this project, upgrading connectivity of the inner city belt, improving passenger demand and reducing vehicle congestion in the downtown Boston area [59, 65]. Another target of Red-Blue connector would be to allow redundancy, that would allow more flexibility needed for Red Line maintenance.

4.7 Discussion

This chapter has identified a number of bottlenecks associated with physical deficiencies long the Red Line. In each case the bottlenecks impacts train operations, service to passengers and propagated delays elsewhere in the system (even throughout). Figure 4-1 summarizes the structural causes of bottlenecks in rail systems, in three categories: 1) alignment deficiencies, 2) inadequate infrastructures, 3) degraded infrastructures. Figure 4-32 shows the largest bottlenecks for the MBTA Red Line, and their inter-relationship affecting train headways.

The largest immediate impacts of the bottlenecks along the system are operational reliability and headway variations, but we should also consider hidden costs associated with structural bottle- necks, and areas of high maintenance that are associated with and can cause disruption (or safety incidents). Here the costs of maintenance or renovation must be offset by larger costs associated with sudden failures repairs, and increased risks to operation disruption.

89 Finally, when looking at the whole Red Line route, it is clear that the bottlenecks, are inter- connected and created by multiple factors. It is challenging to improve the system by addressing a single structural element. By identifying all the deficiencies in the bottleneck areas we could capture multiple projects within one large design. There is a need to devise a strategy to address improvements in a more holistic full network outlook to both get meaningful system improvements and optimize design and construction process.

90 Figure 4-1: Sources of structural bottlenecks in a rail rapid transit system

Figure 4-2: Horizontal curve example with definitions for design (Commuter rail design manual , 1996)

91 Figure 4-3: Curvature and related formulas (Commuter rail design manual , 1996)

92 Figure 4-4: Superelevation equilibrium along a curved track with the inner rail lowered compared to the outer rail (Commuter rail design manual , 1996)

Figure 4-5: Vertical curvature of track alignment, and grade difference

93 Figure 4-6: Plan of Boylston station from 1898, with the sharp curvature still part of the current alignment (Wikimedia Common )

Figure 4-7: Current alignment of the Green line at Boylston station with the base map of the current urban setting above the station

94 Figure 4-8: Red Line maintenance restrictions, Contractor guideline MBTA [87]

Figure 4-9: Alewife station is marked in the aerial along with passing Commuter rail tracks south of the station (Esri, 2020)

95 Figure 4-10: The schematics of Alewife terminus area, with the isalnd platform, crossover in front of the station and the storage space at the back of the station. (MBTA Blue book, 2014)

Figure 4-11: Plan of the Alewife, and platform location and the Alewife Brook Parkway

96 Figure 4-12: Plan and vertical section alignment of the Red line approaching Alewife station

Figure 4-13: Operation of the crossover in front of the terminus station, and its movement, adding passage time to switch between tracks (TCQSM, 2013 [102])

97 Figure 4-14: The most congested roads in Massachusetts, on an average weekday (Congestion in the Commonwealth, 2019)

(b) shown closed parking space at Alewife garage, (a) the state of structural beams at Alewife garage, with crumbling concrete from the sealing 2018

Figure 4-15: Examples of structural problems at Alewife garage, with much of the structure leaking, crumbling, or concrete spilling

98 (b) state of reinforced concrete elements (a) deterioration of upper tunnel slab

(d) seepage and deterioration of structural joints be- (c) severe concrete segregation in tunnels tween slurry walls close to third rail

Figure 4-16: State of the tunnels behind Alewife platform

99 Figure 4-17: Schematics of rail at Braintree station, one island platform serves the train tracks, there are no yard facilities

Figure 4-18: Aerial view of Braintree station, including storage tracks for the Red Line and the Commuter rail station

100 Figure 4-19: Rail schematics of Ashmont station with platforms on both sides of the station, with a connection between them a floor above the platforms. The tracks continue to Codman yardand connect to the Mattapan service.

Figure 4-20: Aerial of Ashmont station along with the Mattapan connection and Comdan Yard, located south-west of the station. (Google earth)

101 Figure 4-21: Ashmont Red line Station and Codman train storage yard. The map shows boundaries of the properties, the dense residential development surrounding the area, and Park

Figure 4-22: Proximity of Park street and Downtown Crossing Red Line stations

102 Figure 4-23: Block signaling system and speed codes for Pask and Downtown Crossing stations (formerly Washington station) (MBTA Block layout and speed commands, 1995)

Figure 4-24: Schematics of Park Street station and Downtown Crossing Station existing (a) and proposed configurations

103 Figure 4-25: Red Line alignment bordering Harvard University, inside the map shows the property ownership

Figure 4-26: Harvard station alignment, and the curves on both sides of its approach

104 Figure 4-27: Aerial view of Columbia Junction andimmediate surrounding (Looking North)

Figure 4-28: Columbia junction alignment showing track locations and merger as tracks go under- ground at Andrew portal. (MBTA 1968)

105 Figure 4-29: Variation of the headway for Both Ashmont and Braintree branches for the Month of October, between 4pm - 6pm Northbound (Wolofsky, 2019

Figure 4-30: A map of Downtown Boston showing all MBTA rapid transit lines and their inter- secting stations

106 Figure 4-31: Proposed configuration for the Red-Blue connection (Red-Blue connector report, 2018 [65])

Figure 4-32: Summary of the transit bottlenecks along the Red line, aligning exactly with the structural bottlenecks (Wolofsky, 2019)

107 Table 4.1: Commuter rail geometric design requirements

Design Speed Max curve Max curve mph with 1.5" Eu with 2.5" Eu

40 6 ∘-42’ 7 ∘-49’ 50 4 ∘-17’ 5 ∘-00’ 60 2 ∘-59’ 3 ∘-28’ 70 2 ∘-11’ 2 ∘-33’ 80 (79) 1 ∘-43’ 2 ∘-00’ 100 1 ∘-04’ 1 ∘-15’

revision 1, Commuter rail Geometric Design Criteria, 1996)

Table 4.2: Statistical station occupancy results - only above 3 minute headway

Station Occupancy Re-occupancy Combined

Mean Mean +2SD Mean SD Mean + 2SD (Adjusted) +Min Adjusted

Park Street SB 116 34 183 80 263 Downtown Crossing SB 105 32 168 61 249 Charles MGH SB 97 45 187 2(54) 241 Harvard NB 100 32 165 0(68) 233 Harvard SB 86 40 166 56 222 Central NB 79 42 164 49 213 Charles MGH NB 79 39 157 0(53) 210 Kendall SB 80 33 146 64 210 South Station SB 83 21 125 81 206 Broadway NB 66 33 132 67 199 Central SB 69 31 132 52 184

SB = Southbound , NB = Northbound ; Downtown Crossing and Park Street NB both had block recording malfunction for the whole month of analyzed am/pm peak data.

108 Chapter 5

Case Study - South Boston Rail Corridor

5.1 Introduction

After identifying and assessing the bottlenecks of the whole Red Line, this chapter proposes a scheme that can improve the bottleneck at Columbia Junction (improving services on the Red Line), double tracking Commuter rail (Old Colony lines) and upgrading JFK/UMass station (com- bined accessibility to all public transit services) through re-alignment of rail tracks through the South Boston rail corridor. JFK/UMASS station is the holding location for out of order train ar- rivals before the Red line branch merger, while Columbia Junction is the physical grade-separated flying junction connecting Cabot Yard Red Line track that feeds into the system andthetwo Red line branches (into merged tracks at Andrew tunnel portal, merging 4 into 2 tracks). This bottleneck is very crucial to the system as detailed previously. While replacing the junction itself could mitigate impact of frequent maintenance (and malfunction closures) it could not affect the out-of-order branch train arrivals JFK/UMASS station (located 500 ft from the junction). The re- pairs usually involve regular maintenance are done for track and circuit degradation, and flooding related repairs (i.e., the junction tunnels are susceptible to flooding, due to the low elevation and cause damage to the signaling system and third rail). For the Commuter rail, the South Boston rail corridor already poses a critical bottleneck, constraining the trains frequency for 3 services utilizing the single track. With the current high demand for the Commuter rail, and planned service expansion (South Coast Rail, adding additional rail line to Old Colony track operation) and projection for the need for higher frequency rail services in the near future it is crucial to

109 change the single track configuration. We have explored the redesign of a large section ofthe South Boston rail corridor to see if we could capture as much state of good repair, improve rail infrastructure facilities, support regional rail plans and address structural bottleneck (out of order trains arriving at JFK/UMASS station and Columbia junction train congestion) within a single project. Assessing with a holistic approach the full MBTA right of way parallel to the Red Line in south Boston to optimize scope of project, challenges and significant rail improvements. The proposed design will accomplish: 1) Improve Red Line service by reducing out-of-order trains (and associated propagation of delays within the system); 2) Upgrading Commuter rail services (by dou- ble tracking) to enable more frequent regional rail service. 3) Improve operations of JFK/UMASS station by providing better connection between Red Line and Commuter rail; 4) Simplifying lay- out and reducing usage at Columbia junction (reducing maintenance and junction train capacity constraint); 5) Address multiple state-of-good-repair infrastructures reducing rapid transit current backlog.

5.2 South Boston Rail Corridor

Figure 5-1 shows the South Boston rail corridor, comprising three rail lines, the Ashmont and Braintree branches of the Red Line and the Commuter Rail (i.e. operating on the Old Colony rail track ). Figure 5-2 shows span A (from Andrew portal to Victory St rail bridge in Dorchester) of the corridor which is the focus of the proposed improvements. The rail corridor was originally bought by the MTA from a group of private rail companies, and later inherited by the newly formed Massachusetts Bay Transportation Authority (MBTA, 1964). The full occupancy of today’s right of way (ROW) was completed the same year with the purchase of the Old Colony tracks from New Haven Railroad, while the track alignment configuration along the corridor dates from 2001. The Red Line branch trains transport more than 60,000 commuters daily along this corridor to downtown Boston [81,85] (i.e. approximately 50% of Red Line ridership on weekdays), with a rush hour peak frequency of 4.5 minutes along the merged track (9 minute frequency for each branch). While the Commuter rail transfers approximately 10,000 people through the same corridor every weekday (each direction) [81]. In recent years there have been growth of 200% (between 2012 and 2018 [37]) in passenger demand on Commuter rail lines at Quincy station, which provides a faster commute between Quincy and South station than the Red Line [37].

110 All bridge structures along the span between South Station and Victory St bridge in Dorchester, Fig 5-2, were constructed prior to 1971 including the flyovers at Columbia Junction (Fig 5-9) and Milton DeVaughn flyover (Fig 5-8), the abandoned Conrail passage (Figure 5-12) beneath the Ashmont branch and the rail bridges (Fig 5-19, 5-3b) grade separating road and rail along the alignment. The rail track configuration dates from the opening of the JFK/UMASS Commuter rail station (2001). The Red Line shares the right-of-way (ROW) with the Commuter rail track from Cabot Yard to Braintree station (a total distance of 9.7 miles, seen in Fig 5-1). Three Commuter Rail services (Old Colony to Middleborough/Lakeville and Kingston/Plymouth; and Greenbush to Cohasset/Scituate) share a single track for much of the distance between South Station and Braintree (approximately 8.7 miles) with the exception of an isolated 2.3 mile section of double track (span B, Fig 5-1). We have considered this situation and believe that there can be significant long-term benefits in double-tracking two sections of commuter rail: A) Columbia Junction to Victory Rd. Dorchester (2.6 miles) and C) Hayward Rd., Quincy to Braintree (4.8 miles) as seen in Fig 5-2.

The current Commuter rail services include up to 6 trains per hour on the single track of span A, and are constrained by single-track operation. While service demand projections show future increase [67, 72, 78], and plans for expanding services reaching to Fall River and New Bedford (currently under construction) for the South Coast Rail project [66, 121]. Double tracking this corridor will enable substantial improvement to services while also improving safety and reliability and providing redundancy for maintenance operations.

5.2.1 Key project constraints

∙ There should be no weekday service interruptions for Red Line. More than preserving fre- quency on the Red Line through South Boston, interruptions willadd to the severe traffic congestion, economic and long term ridership impacts. MBTA ridership is skewed 70% to- wards the Braintree branch, disruptions on this route will add to traffic congestion in Route 3 and I93 from Quincy to Boston.

∙ Passenger volumes on the Commuter rail services are much lower than the Red Line but there is little capacity of the Red Line to absorb Commuter rail passengers at rush hour (at

111 Braintree or stations). The three Commuter lines along the corridor have seen a sharp rise in ridership between FY2012 and the FY2018 (shown in Table 5.1 taken from CTPS counts and [81], and are projected to grow in demand). The Commuter rail is more frequently used during the summer and weekends and includes special services from Boston to Cape Cod (CapeFlyer)

∙ The Cabot Yard maintenance and storage facility currently provides a direct feeder access to both the Ashmont and Braintree branches of the Red Line (SB and NB) and also dispatches trains NB to Alewife for operations. In order to achieve the target 3 minute headway during peak hours for the Red Line services. Any alignment redesign along the south Boston rail corridor must include flexibility to feed trains to and from Cabot Yard.

∙ We assume that any land acquisition (beyond the existing MBTA owned ROW) could cause excessive costs or delay in project execution. This projects has a significant constraint of the current ROW that is tightly bounded between residential structures and the I93 highway (MassDOT property). This provides both a physical constraint 1 and passage challenges for access to construction site.

∙ Existing stations (and platforms) are assumed as hard geometric constraints. Our proposed scheme aims to minimize any changes or disruptions to those existing infrastructures.

In addition those regular challenges that affect the feasibility of the project, there are anum- ber of other constraints affecting the temporary phases of construction. Those constraints will require compliance in the design of construction sequence to ensure project feasibility and efficient execution.

∙ Rail track for Commuter rail and Red Line are forbidden to cross at grade even temporarily during construction work. Although they both share the same , Red Line and Commuter rail lines can’t operate on the same tracks, due to the third rail DC power used for the Red Line.

∙ The MBTA ROW is bounded on both sides along most of section A (Fig 5-2). From Savin Hill station north to the Milton Devaughn flyover (Fig 5-8, located 2000 ft. south of JFK/UMASS

1i.e. the re-development of the GLX project subjected the project to lengthy delays [107].

112 station), MBTA property is bounded by I-93 to the East and by residential and light industrial areas (especially between Savin Hill and JFK/UMASS stations), restricting construction options within the existing ROW. Any construction changes along the alignment require a more rigorous preliminary design to verify accessibility for construction.

∙ Along the South Boston rail corridor (Braintree station to Cabot Yard), there are many existing infrastructures (e.g. bridges or high retaining walls supporting active highways) that constrain track elevations and locations. The proposed schemes focus most of the construction in the proximity of Savin Hill station, between Freeport bridge and Savin Hill station platform (Fig 5-11 and 5-3).

∙ The proposed re-design must comply with current MBTA regulations for , hor- izontal and the vertical alignments of both Red Line and Commuter rail. For the Commuter rail the maximum vertical slope is 0.7% to 1.5% at maximum with appropriate curvature to maintain its 60 mph (79 mph in design, but the allowed actual speed is 60 [mph]) [80]. The Red Line branches, have a maximum speed 25 mph with a maximum allowed slope with a maximum of 2.5% [87].

∙ All infrastructure assets along section A span are in need of renovation (bridges, stations and retaining walls). For example, actual train speeds over the Milton Devaughn flyover were found to be very low, close to 0 mph with allowable speed of 10/15 mph (Zhou, pers. comm., 2019).

5.2.2 Proposed rail corridor improvement

Our goals for this project are to improve Red Line and Commuter rail services. For the Red Line this involves reducing out-of-order train arrivals and congestion at the branch merger, in order to enable 3 minute frequency. This is achieved by optimizing the Red Line alignment through by mov- ing the Red Line junction immediately south of Savin Hill station, reducing congestion/frequency of trains at Columbia junction and freeing space between Savin Hill station and Columbia junction to double track Commuter rail. Lastly, the project includes state of good repair to all infrastruc- tures along section A, reducing their impacts on current passage time, incident probability and driver variability (especially along Red Line branches). The following sections provide three design

113 alternatives, that focus construction activities in the vicinity of Savin Hill station. The alternatives differ in operational impacts, in construction sequencing and in track connections to CabotYard.

5.3 Alternative A

Figures 5-4 and 5-5 show the final configuration of the proposed alignment. Which includes double-tracked Commuter rail lines from Victory road Bridge to Cabot Yard (approximately 2.6 mile), and merging of the Red Line branches south of Savin Hill station. Figure 5-6 shows the track schematics for the current and proposed alignment. The superstructures of the Park St and Freeport St bridges will be widened in order to accommodate an additional Commuter rail track.

Figure 5-13 shows the final configuration for the proposed Red Line branch merger between Freeport St Bridge and Savin Hill station. At the Freeport St bridge, the two Commuter rail tracks lie between the Ashmont and Braintree branches of the Red Line. Moving northwards, towards Savin Hill station, the Braintree branch tracks pass beneath the commuter rail through a single 33 ft wide box-section tunnel that splits into two 17 ft width box sections. Both tunnels rise back to ground elevation (IB) Braintree track merges with the (IB) Ashmont track from the East, while the (OB) Braintree connects to the (OB) Ashmont branch from the West side. The Red Line alignment is at grade immediately South of Savin Hill platform. Double-tracking of the Commuter rail continues all the way north to the Andrew portal entrance (using previous Braintree branch alignment, and only track re-alignment work needed here). The flyover at Columbia junction (north of JFK/UMASS station) ultimately would be partially removed/dismantled/abandoned.

To show the feasibility of the proposed scheme, we have identified the stages that would minimize operational impacts and optimize the construction schedule. In the staging we focus on the section between Freeport Street Bridge and Savin Hill station.

5.3.0.1 Stage A1

Figure 5-14 shows the first stage of construction, involving preliminary site work expanding the right of way. Zone 1, comprises a 15 ft expansion East of the right-of-way for detour of temporary track alignment (over the length of 1275 ft) and for building new retaining walls for the new

114 embankment immediately North of the Freeport St bridge abutment. The expansion of the ROW will be made only within the property boundaries of the MBTA, with access to the construction site from Freeport St, as seen in Fig 5-10. Zone 2 (Fig 5-14) is a temporary right of way expansion on the West side to enable detour of the Ashmont branch tracks (detour length 1100 ft with max West track realignment of 36 ft). The detour will enable construction of the concrete Braintree underpass previously used by Conrail. Most of Zone 2 is within MBTA property, but will require temporary occupancy of a parking lot seen in Fig 5-11 (total area approximately 2700 푓푡2). In both construction zones, the height of the existing, and future retaining walls is no more than a 10 ft. as the MBTA ROW is elevated above the street level.

5.3.1 Stage A2

During Stage A2, Fig 5-15, the Commuter rail would terminate at Quincy center to enable con- struction of the new Red Line underpass. Section 5.3.4 discusses possible mitigation strategies to address Commuter rail passengers during this period. The Ashmont branch tracks will be realigned West of the current alignment over a length of 1100 ft (up to 35 ft Westward movement), with IB and OB tracks at grade (El +20 ft 2 and will merge back to the original alignment approaching Savin Hill station platform. The Braintree branch tracks will be realigned up to 22 ft West of its current alignment, over a length of 1905 ft North of the Freeport St bridge.

Stage 2 comprises four different construction zones: Zone 1 (marked in Fig 5-15) is also bounded on both sides by the Red Line branches, with an average width of 70 ft and length of 500 ft. Work in this zone will involve the removal of the degraded Conrail underpass (marked in Fig 5- 12), and construction of a new box with a perpendicular width of 17 ft and length of 136-150 ft. Replacement of the old Conrail box is necessary as it conflicts with the proposed new underpass for the IB Braintree. The new tunnel section will be precast with reinforced concrete, and assembled on-site, to reduce the time-frame for construction and interference with track operations. The existing retaining walls between the current Commuter rail track and the Ashmont track (seen in Figs 5-15, 5-17) will be removed in order to accommodate wing-walls for the new tunnel. At the same construction zone the first half of the tunnel for the Braintree branch will also be built.This segment comprises two separate tunnels for IB and OB tracks. The two tunnels are 17 ft wide

2All elevations are NAVD88 datum

115 each with length of 200 ft. The access to construction zone 1 will be through Park St, as seen in Fig 5-18.

Construction zones 2 (Fig 5-15) and 4 (Fig 5-24) are needed for retrofit of the Freeport St and Park St bridges, respectively. Both of these bridges require superstructure modifications, to accommodate double tracking of the Commuter rail lines. Both bridges were originally built in 1968 and the deck structures for the Commuter rail track on both bridges were replaced in 1992. The Freeport St bridge (Figs 5-19 and 5-20) superstructure would be replaced with a similar, but wider deck (as is used for the Braintree branch tracks 26 ft wide vs current 14’-6” structure). The deck for the Ashmont branch tracks was not replaced in 1992 and is in more urgent need of renovation/replacement. The best option would be to replace the superstructure with a similar structural deck as used for the Commuter rail and the Braintree branch tracks at Freeport St 3.

The Park Street bridge (Figs 5-21, 5-3) the width of the bridge deck would need to be widened to 26 ft. This change will require reconstruction of both abutment walls on the west side. Al- though both abutments were renovated at 1992, the North abutment shows apparent vertical and horizontal cracks. The Vertical cracks (Figs 5-22 5-23) are located between the supports of the main girders on the abutment bench, and the horizontal crack spans across the abutment wall approximately at 1/3 of its height.

The last construction site for this phase, Zone 3, is shown in Fig 5-24, between Victory St Bridge and Park St bridges (total length of 1385 ft). Along this segment, the existing track-bed will need to be expanded about 5 ft Eastwards, while the current Commuter rail track would be realigned Westwards by up to 7.5 ft towards the Braintree branch, and double tracked along this construction zone.

5.3.2 Stage A3

After the expansion of the embankment between Victory St and Park St bridge this segment will be realigned to the final location of the double track for the Commuter rail (full layout inFig 5-24). This stage will also require suspension of Commuter rail services at Quincy center to enable access to construction site between the two Red Line branches. The overall re-design of stage 3

3At Freeport St, the Ashmont branch has a badly degraded concrete superstructure, while the Braintree branch and the Commuter rail supported by main girders with a concrete slab superstructure

116 can be seen by comparing Figs 5-15 and 5-16. Between Freeport St bridge and Savin Hill station, the Braintree tracks would be realigned Westwards towards the Ashmont Branch (25 ft. in total), compared to Stage 2. The realigned length is approximately 1800 ft. The top of rail will be elevated to accommodate the tunnel structure (corresponding to the final alignment elevation), with 2.0% vertical slope over a length of 900 ft. The Ashmont Branch, would be realigned back to its pre-existing alignment and elevation, (temporary detour can be disassembled and parking lot returned).

Stage 3 of the construction will be done in a single zone (Fig 5-16, for completion of the box section underpass for the Braintree branch lines, with access to construction zone shown in Fig 5-10. During this stage, the first 387 ft of the underpass tunnel would be built. This halfof the tunnel accommodates both IB and OB Braintree tracks, with an internal width of 36 ft. The entrance to the tunnel will require a vertical grade of 2.0% (current used slope is minimal at 0.05%) to reach a clear height of 17 ft. for the tunnel. The temporary retaining walls along the Eastern embankment can be removed and wing walls for the tunnel entrance would be built. Finally the OB Braintree track elevation would be matched to pre-existing approaching Savin Hill station, in order to allow at-grade merge with the OB Ashmont.

5.3.3 Stage A4

The final stage of construction for Alternative A involves realignment of the Braintree branch and Commuter rail tracks (Fig 5-13), the final track and infrastructure configuration along the constructed span marking a location switch between the Commuter rail and Braintree tracks. The Red Line tracks along the old Braintree alignment should replaced by Commuter rail tracks (no 3rd rail), between Savin Hill station and JFK/UMASS station. The realignment for the Braintree branch tracks would be East of its pre-existing alignment (Stage 3), and passing through the new tunnels. At the same time, the tracks for the underpass, the new box tunnel and the new at grade cross-over for the Red line branches would be installed. North of the tunnels both the OB and IB tracks are at the new grade, same as the Ashmont tracks.

Stage 4 would also includes dismantling of the existing flying junction of the Red Line tracks at Columbia junction (North of JFK/UMASS Station). The proposed scheme eliminates part of Columbia junction, as the Red Line branches merge 1.5 miles further South (Fig 5-9). At this

117 location, the owned right of way is substantially larger (i.e., 6 Red Line tracks, including 2 tracks from Cabot Yard and 1 Commuter rail track in the cross section), with access East of right of way. The additional width will accommodate detour for one of the Cabot Yard feeders in order to remove the flying crossover without disrupting operations. (Note: the removal of Columbia junction would be the last construction of this project, when the new Red Line merge is already active. The track final alignment of the Commuter rail north of Savin Hill station will follow the tracks of theformer Braintree branch, and will utilize the former Red Line platform of UMASS/JFK station.

5.3.4 Impacts on operations

Alternative A assumes priority for higher volume Red Line services (compared to the Commuter rail) passenger volume, and attempts to minimize disturbance on Red Line operations. All stages of construction would have reduced speed codes for both the Red Line branches due to the proximity of construction (current speed code is 25 mph and will be reduced to the 10/15 mph). Reduced speed codes effected three signal blocks length along Red Line.

During Stages 2, 3 and 4 there will be a few weekend shutdowns for the Red Line south of UMASS/JFK operations to accommodate stage track work realignments and bridge deck replace- ments.

Commuter rail services will be suspended during stages 2 and 3 between and South station. Mitigation to passenger disruption and inconvenience (i.e, long-term impacts on ridership) could be done by providing alternative service for Commuter rail passengers (between Quincy center and South Station) transferring to trains utilizing the Red Line Braintree tracks to South Station. For stage 4, All three rail services would resume regular operations, with single location speed reduction, around Columbia junction construction (being partially removed at this stage).

5.4 Alternative B

The goals of Alternative B are to reduce impacts of construction on rail services for both the Red Line and Commuter rail passengers. This alternative also includes direct access from Cabot Yard

118 to the OB and IB Braintree tracks. This section focuses on the differences between alternatives A and B.

Figures 5-25 and 5-26 give an overview of Alternative B showing the span of approximately 2.6 miles, while Figure 5-27 shows the details of track final track configuration between Savin Hill station and Freeport St bridge. This scheme connects Cabot Yard facility to the Red Line at 5 different locations 1,2) to IB and OB Red Line North of UMASS/JFK station (merged tracks); 3,4) to IB and OB Braintree South of Savin Hill; 5) to IB Ashmont north of Savin Hill platform. Figure 5-28 shows the schematics of the branch merger south of Savin Hill station platform from a single feeder track.

Northwards from Freeport St bridge there are two Commuter rail tracks located between the Red Line branches. Figures 5-29 - 5-34 show the cross sections of the right of way for the proposed Alternative B at six locations (Fig 5-27) between Freeport St rail bridge and Savin Hill station. The Commuter rail tracks rise in elevation with the Ashmont branch (section 2, Fig 5-30). At section 3 5-31 a retaining wall separates the Commuter rail from the underpass tunnel for the Cabot Yard feeder. Section 4 (Fig 5-32) shows the separation of the Braintree IB and OB tracks into two tunnels passing beneath the Commuter rail and above the Cabot Yard feeder. At section 5 (Fig 5-33), the Braintree OB tunnel passes beneath the Ashmont branch tracks, the IB track rises between retaining walls (East of the Ashmont IB). At Section 6 (Fig 5-34) the IB and OB Braintree tracks merge at grade elevation with the Ashmont tracks, immediately South of Savin Hill platform. The Cabot yard feeder, is also at grade and connects to the IB Braintree track in this location.

The Cabot Yard feeder track connects to the IB and OB Braintree tracks (At Savin Hill), to IB and OB tracks of the merged Red Line (at pre-existing location at Columbia junction) and has a connection to Ashmont IB immediately North of Savin Hill station platform.

North of Savin Hill station the Commuter rail tracks follow the former alignment of the Braintree branch to JFK/UMASS station, and occupies the former Braintree branch platform (same as Alternative A) improving passenger transfer between the Red Line and Commuter rail.

To show the feasibility of the proposed scheme, we have identified 4 major construction stages that would provide minimal impacts on rail service and enable construction. While the staging process accounts for all construction needed for the completion of the proposed scheme, the main

119 construction site and drawings used in the rest of the report focus on the span between Freeport Street Bridge and Savin Hill station. There are three access routes to the construction sites, Figure 5-10: 1) West of the MBTA ROW through a parallel unpaved parking lot connected to Freeport St.; 2) East of the ROW with access from Freeport St and a paved access road; 3) from the middle of the ROW with access from Freeport rail bridge south of the construction site.

5.4.1 Stage B1

The first stage of construction focuses on the West side of the ROW, and makes realignment ofall branch tracks Eastwards (towards I93, Fig 5-35). The Ashmont branch will be moved 45 ft East over a length of 2000 ft, connecting south of Savin Hill station, (starting approximately 100 ft from the platform), this temporary detour should not affect operation speed code. The Commuter rail and Braintree branch tracks are also moved West (towards I93 by 18 ft), to the current edge of the right-of-way over a length of 2100 ft.

Having all the tracks transferred East, helps create a construction site 55-93 ft wide, 1000 ft long. Here, the abandoned Conrail tunnel box and associated retaining walls, will be replaced to create a future detour for the Ashmont branch tracks. After the removal of these pre-existing structures, part of the new box passage will be installed (Fig 5-36). All the box tunnels used in Alternative B have the same dimensions, with a clear width of 15.6 ft and height of 17 ft and would be built in precast segments to complete the construction process. Stage 1 will build 197 ft length of tunnel. At the end of stage 1 (Fig 5-36) there are two new retaining walls to support the Ashmont branch elevated tracks and the new tunneled underpass. There will be a temporary retaining wall south of the box tunnel (length of 596 ft, up to 10 ft high). The retaining wall North of the new tunnel is a permanent wall with a changing height up to 23 ft and 434 ft length.

5.4.2 Stage B2

In Stage B2 the tracks are all re-aligned Westwards, creating space for construction on the Eastern side of the ROW, Fig 5-37. This is achieved by detouring the Ashmont branch West of its current alignment (i.e, by 100 ft from their Stage B1 configuration) connecting to current alignment near the platform. The Commuter rail and Braintree branch tracks are also realigned West by 65 ft,

120 positioned along the current Ashmont elevated segment (Fig 5-36), above the new completed box tunnel section. The elevation of the tracks matches the final Ashmont level tracks, from with El. +25.7 ft at Freeport Street, to a maximum El. +45 ft, and to El. +14.5 ft at Savin Hill station. The IB Braintree track will be realigned as close as possible to the two elevated tracks (without elevation changes). From El. +25.4 ft of Freeport St bridge, to El. +14.5 ft at Savin Hill platform. The re-alignment temporary affects track curvatures near Savin Hill station. All three tracks have to have a slight curve, to reconnect to their respective original alignment approaching the platform.

Stage B2, Fig 5-38, involves construction of a tunnel box for the Cabot Yard feeder (length of 713 ft with the same interior dimensions used for the Red Line tunnel sections (15.6 x 17 ft). The tunnel will be constructed using precast segment requiring a 20 ft deep excavation, with final top-of-rail El-4.5 ft. Four permanent retaining walls would be installed during this stage, for grade separations in the final alignment, Figs 5-38,5-31 and 5-33.

In order to provide for Stage B3, the superstructure of the Freeport St bridge (Fig 5-19) would be replaced, together with the replacement of the Park St bridge superstructure to accommodate double-tracked Commuter rail (Fig 5-21).

Figure 5-24 shows final zone of construction of this stage, located between Victory St bridge and Park St bridge expanding the embankment and double tracking the Commuter rail as in Alternative A.

5.4.3 Stage B3

In stage B3, construction access uses the middle span of the renovated Freeport St rail bridge (Fig 5-39). The Commuter rail and Braintree branch tracks are realigned Eastwards (72 ft), location similar to Stage 1, and pass over the completed Cabot Yard feeder tunnel.

The track configuration in Stage B3 accommodates construction between the Ashmont branch and Commuter rail tracks, Figure 5-40. The work will involve the installation of two precast tunnels, for the Braintree branch tracks: 1) Completion of the tunnel for OB Braintree track (length 210 ft), and 2) first piece of tunnel for IB Braintree track over a length of 168 ft.Both constructed tunnels have similar TOR at El +14.5 ft.

121 5.4.4 Stage B4

During this stage the tracks are reversed to the configuration used for Stage B2 (i.e, all five existing tracks realigned to the West of the ROW, Fig 5-41). This involves re-aligning of the Commuter rail and Braintree OB tracks on the already elevated terrain of the current Ashmont tracks, and would require no extra work for realignment. The Braintree inbound track passes parallel to two of the previously constructed box tunnels. The track will need a temporary fill to raise TOR to El. +23 ft at maximum, over length of 1600 ft for the IB Braintree track.

Stage B4 construction comprises completion of the Braintree IB tunnel box and completion of a retaining wall close to Savin Hill platform, Fig 5-60. The IB Braintree box will connect to the previous piece (from Stage B3). Grade separation of the Commuter rail is then enabled by extending the retaining wall by 294 ft towards Savin Hill.

After stage B4 of construction the Red Line branches can be moved to their final alignments. Double tracking of the Commuter rail then can be achieved after filling above the new tunnel boxes to the rail required track elevation (of Figs 5-29 - 5-34). Tracks can than be re-aligned between Savin Hill station and JFK/UMASS replacing the Red Line tracks (with electrified third rail) with a Commuter tracks along the existing Braintree tracks (Fig 5-25). The Ashmont branch will be moved to its original track alignment with minimal changes made to its geometry (horizontal or vertical). The last element would be to remove the fill used for the detour of the Ashmont branch. For the Braintree tracks, the at grade merger at Savin Hill station would need to be installed while realigning the tracks. Replacing the current tracks for the Commuter rail between Savin Hill station and JFK/UMass station and replace it by Red Line used tracks, to accommodate for the alignment of the Cabot Yard feeder.

5.4.5 Impacts on operations

Alternative B would enable regular operations of both Red Line and Commuter rail services along the South Boston rail corridor throughout construction. There would still be a number of shut downs for track re-alignment and bridge superstructure replacements. The area South Savin Hill station, would be subjected to reduced speed codes, due to proximity of construction. Both Red

122 Line branches currently operate with 25 mph (at maximum) along this span, with reduction to the allowed speed for the Ashmont branch approaching Savin Hill platform. The maximum speed the Commuter rail can currently operate at south Boston is 60 mph, it would also have a speed reduction, along the Savin Hill construction area to a 20 mph as described in the 1996 Commuter rail design standard book [80].

5.5 Alternative C

The goals of Alternative C are to create complete separation of Cabot Yard dispatch operations to/from South Red Line termini from Columbia junction (feeding trains to IB and OB of the branches at Savin Hill station area), and maintain minimal impacts of construction on rail services as done in Alternative B. Alternative C is very similar to Alternative B (in configuration and staging process), with an additional tunneled passage for the Cabot Yard feeder to complete required track connections. Figures 5-43 and 5-44 shows the full span overview of Alternative C, while Figure 5-45 shows the details of final track configuration between Savin Hill station and Freeport St bridge. The Cabot Yard facility connects to the Red Line at 6 different locations 1,2,3,4) at Savin Hill area connecting to OB Ashmont (track used for dispatched trains to the terminus) and IB and OB Braintree South of the station, IB Ashmont north of Savin Hill platform. Figure 5-46 shows the schematics of the branch merger south of Savin Hill station platform from a single feeder track. 5,6) North of JFK/UMass station for IB and OB Red Line (merged tracks); Northwards from Freeport St bridge there are two Commuter rail tracks located between the Red Line branches.

Figures 5-47 - 5-52 show cross sections of the right of way for the proposed Alternative C for six locations (Fig 5-45) between Freeport St rail bridge and Savin Hill station. Section 1 shows all 6 tracks (2 Commuter rail and 4 Red Line branch tracks) North of Freeport St bridge, at an elevation matching the pre-existing TOR. The Commuter rail tracks rise in elevation with the Ashmont branch, the Cabot Yard feeder is seen merging with the Ashmont OB track (section 2, Fig 5-30). At section 3 5-31 the Cabot Yard feeder underpass is located beneath the Ashmont branch and Commuter rail tracks, while the the second underpass tunnel for the Cabot Yard feeder is separated by a retaining wall from Commuter rail tracks. Section 4 (Fig 5-50) shows the separation of the Braintree IB and OB tracks into two tunnels passing beneath the Commuter rail and above the Cabot Yard feeder (North of the Cabot Yard feeder track split, Fig 5-45). In section

123 5 (Fig 5-51), the Braintree OB tunnel continues and passes beneath the Ashmont branch tracks, the IB track rises between retaining walls (East of the Ashmont IB). At Section 6 (Fig 5-52) the IB and OB Braintree tracks merge at grade elevation with the Ashmont tracks, immediately South of Savin Hill platform. The Cabot Yard feeder, is also at grade and connects to the IB Braintree track in this location.

The Cabot Yard feeder track connects to the IB and OB Braintree and OB Ashmont branch tracks (at Savin Hill station), tp IB Ashmont immediately North of Savin Hill station platform and to IB and OB tracks of the merged Red Line (at pre-existing location at Columbia junction).

North of Savin Hill station the Commuter rail tracks follow the former alignment of the Brain- tree branch to JFK/UMASS station, and occupies former Braintree branch platform (same as Alternatives A and B) improving passenger transfer between the Red Line and Commuter rail.

To show the feasibility of the proposed scheme, we have identified 4 major construction stages that would provide minimal impacts on rail service and enable construction. While the staging process accounts for all construction needed for the completion of the proposed scheme, the main construction site and drawings used in the rest of the report focus on the span between Freeport Street Bridge and Savin Hill station. There are three access routes to the construction sites, Fig 5-10: 1) West of the MBTA ROW through a parallel unpaved parking lot connected to Freeport St.; 2) East of the ROW with access from Freeport St and a paved access road; 3) from the middle of the ROW with access from Freeport rail bridge south of the construction site.

5.5.1 Stage C1

The first stage of construction focuses on the West side of the ROW, and makes realignment ofall branch tracks Eastwards (towards I-93, Fig 5-53). The Ashmont branch will be moved 45 ft East over a length of 2000 ft, connecting south of Savin Hill station, (starting approximately 100 ft from the platform), this temporary detour should not affect operation speed code. The Commuter rail and Braintree branch tracks are also moved West (towards I-93 by 18 ft), to the current edge of the right-of-way over a length of 2100 ft.

Having all the tracks transferred East, helps create a construction site 40-93 ft width 2000 ft length. Here the abandoned Conrail tunnel box and associated retaining walls under the Ashmont

124 branch, will be replaced by a new box passage for the OB Braintree over the length of 197 ft (Fig 5-54). The Cabot Yard feeder underpass West of the right-of-way (for OB Ashmont) with a length of 296 ft is installed. All the box tunnels used in Alternative C have the same dimensions (with the exception of the feeder track split), with a clear width of 15.6 ft and height of 17 ft and would be built in precast segments to complete the construction process. At the end of stage 1 (Fig 5-54) there are two new retaining walls to support the Ashmont branch elevated tracks and the new tunneled underpasses. There will be a temporary retaining wall south of the box tunnel (length of 596 ft up to 10 ft height). The retaining wall North of the new tunnel is a permanent wall with a changing height up to 23 ft and 434 ft long.

5.5.2 Stage C2

For Stage C2 all tracks are re-aligned Westwards, with construction on the Eastern side of the ROW, Fig 5-55. This is achieved by detouring the Ashmont branch West of its current alignment (i.e, by 100 ft from the Stage 1 configuration) connecting to pre-existing alignment near platform. The Commuter rail and Braintree branch tracks are also realigned West by 65 ft, positioned along the current Ashmont elevated segment (Fig 5-36), passing above the tunneled sections completed at Stage 1. The elevation of the tracks matches the final Ashmont level tracks, from El. +25.7 ft at Freeport St, to a maximum El. +45 ft (to El. +14.5 ft approaching Savin Hill station platform). For IB Braintree track, it will be realigned as close as possible to the two elevated tracks, without elevation changes, between 25.4 ft coming from Freeport bridge, and reducing elevation to 14.5 [ft] parallel to Savin Hill platform. The re-alignment temporary affects track curvatures near Savin Hill station. All three tracks have to have a slight curve, to reconnect to their respective original alignment approaching the platform.

Stage 2, Fig 5-56, involves construction of a tunnel box for the Cabot Yard feeder (length of 592 ft of the same interior dimensions used for the Red Line tunnel sections (15.6 x 17 ft), and an additional 101 ft of up to 40 X 17 ft tunnel box for the feeder track split (to connect to the separate branch tracks)). The tunnel will be constructed using precast segment requiring a 20 ft deep excavation, with final top-of-rail El. -4.5 ft. Four permanent retaining walls would be installed during this stage, for grade separations in the final alignment, Figs 5-38,5-31 and 5-33.

In order to provide for Stage 3, the superstructure of the Freeport St bridge (Fig 5-19) would

125 be replaced, together with the replacement of the Park St bridge superstructure to accommodate double-tracked Commuter rail (Fig 5-21).

Figure 5-24 shows final zone of construction of this stage, located between Victory St bridge and Park St bridge expanding the embankment and double tracking the Commuter rail as in Alternative A.

5.5.3 Stage C3

In stage C3, construction access uses the middle span of the renovated Freeport St rail bridge (Fig 5-57). The Commuter rail and Braintree branch tracks are realigned Eastwards (72 ft), location similar to Stage 1, and pass over the completed Cabot Yard feeder tunnel.

The track configuration in Stage C3 accommodates construction between the Ashmont branch and Commuter rail tracks, Figure 5-58. The work will involve the installation of three precast tunnels, for the Braintree branch tracks and Cabot Yard feeder track: 1) Completion of the tunnel for OB Braintree track (length of 210 ft), 2) first piece of tunnel for IB Braintree track over a length of 168 ft, 3) the last tunnel piece for the Cabot Yard feeder track (150 ft length), completing the underpass connecting the feeder track to the OB Ashmont track. All constructed tunnels have similar TOR at El. +14.5 ft.

5.5.4 Stage C4

During this stage the tracks are reversed to the configuration used for Stage C2 (i.e, all five existing tracks realigned to the West of the ROW, Fig 5-59). This involves re-aligning of the Commuter rail and Braintree OB tracks on the already elevated terrain of the current Ashmont tracks, and would require no extra work for realignment. The Braintree inbound track passes parallel to two of the previously constructed box tunnels. The track will need a temporary fill raise TOR by 23 ft at maximum, over length of 1600 ft for the IB Braintree track.

Stage C4 construction comprises completion of the Braintree IB tunnel box and completion of a retaining wall close to Savin Hill platform, Figure 5-60. The IB Braintree box will connect to the previous piece (from Stage 3). Grade separation of the Commuter rail is then enabled by extending

126 the retaining wall by 294 ft. towards Savin Hill.

After stage C4 of construction the Red Line branches can be moved to their final alignments. Double tracking of the Commuter rail then can be achieved after filling above the new tunnel boxes to the rail required track elevation (of Figs 5-47 - 5-52). Tracks can than be re-aligned between Savin Hill station and JFK/UMASS replacing the Red Line tracks (with electrified third rail) with a Commuter tracks along the existing Braintree tracks (Fig 5-43). The Ashmont branch will be moved to its original track alignment with minimal changes made to its geometry (horizontal or vertical). The last element would be to partially remove the Ashmont branch detour and complete the at grade connection between the Cabot Yard feeder track and Ashmont OB. For the Braintree tracks, the at grade merger at Savin Hill station would need to be installed while realigning the tracks. Replacing the current tracks for the Commuter rail between Savin Hill station and JFK/UMass station and replace it by Red Line used tracks, to accommodate for the alignment of the Cabot Yard feeder.

5.5.5 Impacts on operations

Alternative C would enable regular operations of both Red Line and Commuter rail services along the South Boston rail corridor throughout construction. There would still be a number of shut downs for track re-alignment and bridge superstructure replacements. This Alternative, while very similar to Alternative B will involve a longer construction time-span for completion of the additional feeder track connection. The area around South Savin Hill station, would be subjected to reduced speed codes, due to proximity of construction activities. Both Red Line branches currently operate with 25 mph (at maximum) along this span, with reduction to the allowed speed for the Ashmont branch approaching Savin Hill platform. The maximum speed the Commuter rail can currently operate at south Boston is 60 mph, it would also have a speed reduction, along the Savin Hill construction area to a 20 mph as described in the 1996 Commuter rail design standard book [80].

127 5.6 Benefits

5.6.1 Common benefits of proposed projects

The proposed schemes addresses two large bottlenecks in the South Boston rail corridor, associated with Columbia (flying) Junction for the Red Line and the single track operations of Commuter rail, that must accommodate 4 line services (including the future South Coast Rail). Double-tracking the Commuter rail over the proposed 2.6 mile span, would create a 4.9 mile corridor of double track, enabling more frequent services.

The Red Line new alignment shifts the branch merger South of Savin Hill station, reducing the length of separate (and parallel) track alignment between the two branches, and eliminating infrastructure and station differences between the two branches. We believe that those changes will mitigate delays occurring at JFK/UMass station where is a high percentage of out-of-order train arrivals and enable reduction of train headways. This proposed will enable Savin Hill to be served by all Red Line trains, while eliminating Braintree branch above the Commuter rail (at Milton Devaughn Flyover, Fig 5-8 where trains operate at very low speed. Eliminating these differences, and their impact the headway time passing through the flyover and dwell time at Savin Hill, will mitigate the out of order branch arrivals at JFK/UMass during peak hour (currently spacing 2 minute scheduled difference in arrival at the merge).

For both rail services, the new configuration improves efficiency of services for passengers at JFK/UMass station. The merged Red Line platform (simplifying current separate access branch platforms) and the Commuter rail platform (previous Braintree branch platform) will improve passenger accessibility. With JFK/UMass growing in demand as a multi-modal transit stop, this benefit will help stations operations accommodate its future demand projections.

Currently, the Red Line branch trains operate at a 50:50 split in trains, altogether the ridership on the Braintree branch is substantially larger (70:30), causing significant station crowding and passengers left behind. An additional benefit for Braintree branch passengers arises from the ability to utilize Commuter rail instead of Red Line for faster trips to South Station, and higher frequency/capacity for service (i.e. as already been seen by CTPS passenger counts in recent

128 years [37]).

The key benefit for all solutions is the short time span and low operational impacts during construction. The current configuration of the proposed span changes incorporates the feasibility check of all the final track geometry vertical and horizontal, for the appropriate grades, slopesand curvatures. The solution is utilizing almost exclusively only the existing ROW property of the MBTA. All Alternatives achieve multiple improvements (combining multiple stand alone projects) to MBTA rail services within one large construction staging sequence enabling optimized cost, time and project execution helping address system safety, reliability and project backlog challenges.

5.6.2 Alternative A benefits

This solution was designed with a potential benefit not only for the improvement of the rail corridor but to improve the heavily congested [50] I-93 highway (one of the five most congested links in the state [95], whose expansion has been ordered by the state [38]). The re-alignment frees a width of the MBTA right-of-way that could be given for the expansion of the bounded highway, the width could potentially provide at least one more lane and shoulder for the highway. This solution has the lowest construction time span of the three Alternatives.

5.6.3 Alternative B benefits

There are two key benefits to this alternative: 1) No operational shutdowns for either theCom- muter rail or the Red Line during construction. This proposed will involve only weekend closures (for track re-alignment and bridge repairs), ensuring minimal disruption for commuters. 2) Re- ducing significantly train quantity at JFK/UMASS, due to the new separate connections between Braintree IB and OB and Ashmont IB tracks and the Cabot Yard feeder at Savin Hill station area (Fig 5-27). These three feeder track connections on the separated branch tracks reduce traffic frequency over the combined Red Line alignment span and improve operations.

129 5.6.4 Alternative C benefits

Similar to Alternative B, alternative C involves as a binding constraint keeping regular operations for the Red Line branches and the Commuter rail lines, along with providing Cabot Yard feeder track connections South of Columbia flyover junction (mitigating train congestion bottleneck at Columbia junction due to dispatched train quantity). For this solution we now have 4 separate connections of the Cabot Yard feeder tracks, to all 4 Red Line tracks (seen in Fig 5-45), without utilizing the merged Red Line tracks, connecting after the branch split at Savin Hill station.

130 Figure 5-1: Full span of the chosen South Boston corridor, and showing the ROW owned by the MBTA between Andrew portal and Cabot Yard South to Braintree terminus. Marked on the figure, the sub spans A, B, C, split by Commuter rail single or double track

Figure 5-2: Span A - shows the proposed re-designed rail corridor, from Andrew portal to Victory St rail bridge.

131 (a) Freeport St rail bridge (b) Park St rail bridge

(d) DWG of track alignment, from the MBTA, with (c) Typical ROW between Freeport St and Victory ownership boundaries, taken from MASS.gov tax St rail bridges parcel 2018

Figure 5-3: Bridges constraining double tracking of Commuter rail for span A

132 133

Figure 5-4: Full alignment for the proposed Alternative A scheme for the South Boston rail corridor (part a) 134

Figure 5-5: Full alignment for the proposed Alternative A scheme for the South Boston rail corridor ( part b) Figure 5-6: Schematics of track alignment in South Boston a) current configuration; b) proposed Alternative A

135 136

Figure 5-7: Existing track Alignment in the area South of Savin Hill Station Figure 5-8: View of Milton Devaughn Flyover bridge, switching currently between the Braintree branch and Commuter Rail tracks

Figure 5-9: View North of JFK/UMASS Station, Columbia flying junction for the Red line branches

137 Figure 5-10: Proposed access to construction sites: (1) Access to the main construction site would be from two different points, depending on stage of construction: east of the MBTA ROW,and between the i93 Highway (2) Through Freeport Bridge utilizing current Commuter rail bridge in order to gain access to the middle of the ROW (3)

Figure 5-11: View of main South Boston rail corridor from Savin Hill Station to Freeport St bridge

138 Figure 5-12: View of abandoned Conrail passage under the Ashmont branch.

139 Figure 5-13: Final proposed alignment at Savin Hill area, Alternative A 140

Figure 5-14: First stage (A1) of construction for Alternative A - Showing the alignment during this stage of construction and the construction sites active during this stage Figure 5-15: Second stage (A2) of construction for Alternative A - Showing the alignment during this stage of construction and the

141 construction sites active during this stage and structural elements built

Figure 5-16: Third stage (A3) of construction for Alternative A - Showing the alignment during this stage of construction and the construction sites active during this stage Figure 5-17: View of abandoned Conrail box and retaining/wing walls supporting the Ashmont branch

Figure 5-18: Access to construction zone 1, through Park St

142 Figure 5-19: Plan view of Freeport St bridge superstructure plans, overlaid on the current (colored) track alignment

Figure 5-20: State of Freeport St Ashmont branch superstructure. (August 2018) 143 Figure 5-21: Plan view of Park St bridge superstructure, overlaid on current (colored) track align- ment

Figure 5-22: Park St bridge North Abutment, under Braintree superstructure. The vertical cracks are marked in yellow

144 Figure 5-23: Park St bridge North Abutment, the horizontal crack is marked, and bulging of the abutment is progressing

145 Figure 5-24: Double tracking of Commuter rail, Victory St to Park St bridge.

146 147

Figure 5-25: Track configuration for proposed Alternative B scheme for the South Boston rail corridor (parta) 148

Figure 5-26: Track configuration for proposed Alternative B scheme for the South Boston rail corridor (partb) 149

Figure 5-27: Final proposed alignment at Savin Hill area, Alternative B Figure 5-28: Track configuration for South Boston rail corridor: a) current state; b) proposed Alternative B

150 Figure 5-29: Cross-section of the ROW, section 1 Alternative B

Figure 5-30: Cross-section 2- showing grade separation of the Commuter rail and Ashmont Red line branch, Alternative B

151 Figure 5-31: Section 3 shows the Cabot Yard feeder underpass separated from Commuter rail and Ashmont branch by retaining wall, Alternative B

Figure 5-32: Section 4 - shows the the location where three separate underpasses for Braintree IB, OB and Cabot Yard feeder pass beneath the Commuter rail tracks, Alternative B

152 Figure 5-33: Section 5 - At this section the Braintree OB passes under the Ashmont branch to connect at grade with Ashmont OB. Braintree IB is separated from the Ashmont branch, Feeder underpass and Commuter rail tracks with retaining walls on both sides, Alternative B

Figure 5-34: Section 6 - Savin Hill station platform, the merged Red Line tracks and feeder tracks use pre-existing elevation, while the Commuter rail has still grade separation from the other tracks, Alternative B

153 Figure 5-35: First stage (B1) of construction for Alternative B - In this figure we see the alignment during this stage of construction, with marked elements of focus for the stage 154

Figure 5-36: In this figure we see the progress of construction by the end ofstageB1 Figure 5-37: Second stage (B2) of construction for Alternative B - In this figure we see the alignment during this stage of construction, 155 with the structures already completed by this stage of construction

Figure 5-38: In this figure we see the progress of construction by the end ofstageB2 Figure 5-39: Third stage (B3) of construction for Alternative B - showing the realignment during this stage of construction, with the structures already completed by this stage of construction 156

Figure 5-40: Progress of construction by the end of stage B3 Figure 5-41: Fourth stage (B4) of construction for Alternative B - showing the realignment during this stage of construction, with 157 the structures already completed in previous stages of construction

Figure 5-42: Progress of construction by the end of stage B4 158

Figure 5-43: Full alignment for proposed Alternative C scheme for the South Boston rail corridor (part a) 159

Figure 5-44: Full alignment for proposed Alternative C scheme for the South Boston rail corridor (part b) 160

Figure 5-45: Final proposed alignment at Savin Hill area, Alternative C Figure 5-46: Track configuration for South Boston corridor: a) current state; b) proposed Alter- native C

161 Figure 5-47: Cross-section of the ROW, section 1 Alternative C

Figure 5-48: Cross-section of the ROW, section 2 Alternative C

162 Figure 5-49: Cross-section of the ROW, section 3 Alternative C

Figure 5-50: Cross-section of the ROW, section 4 Alternative C

163 Figure 5-51: Cross-section of the ROW, section 5 Alternative C

Figure 5-52: Cross-section of the ROW, section 6 Alternative C

164 Figure 5-53: First stage (C1) of construction for Alternative C - showing the alignment during this stage of construction, with marked 165 elements of focus for the stage

Figure 5-54: Progress of construction at the end of stage C1 Figure 5-55: Second stage (C2) of construction for Alternative C - showing the alignment during this stage of construction, with the structures already completed by this stage of construction 166

Figure 5-56: Progress of construction at the end of stage C2 Figure 5-57: Third stage (C3) of construction for Alternative C - showing the realignment during this stage of construction, with the 167 structures already completed by this stage of construction

Figure 5-58: Progress of construction by the end of stage C3 Figure 5-59: Fourth stage (C4) of construction for Alternative C - showing the realignment during this stage of construction, with the structures already completed in previous stages of construction 168

Figure 5-60: Progress of construction by the end of stage C4 Table 5.1: MBTA South Boston Rail corridor demand

Ridership Ridership Growth Line 2012* 2018* %

Middleborough/Lakeville 5006 6863 37.1% Greenbush 4353 6114 40.5% Kingston/Plymouth 5513 6089 10.4%

*The ridership is only counted Inbound to Boston, Demand Outbound is usually considered matching to inbound. **No changes to service levels since 2012 for all the Commuter rail lines along this corridor. ***Information taken from CTPS Commuter rail ridership count report. ***1/3 of total growth is at Quincy Center, where passenger demand grown by 200%

169 THIS PAGE INTENTIONALLY LEFT BLANK

170 Chapter 6

Summary, Conclusions and Recommendations

6.1 Summary

This thesis has reviewed the development and legacy of urban rail networks in Boston. The main focus is on challenges impacting the Commuter rail and Red Line services, considering the physical bottlenecks affecting the Red Line services (and the potential to meet a future 3 minute headway target). The bottlenecks arise from numerous factors including track alignment, station layout (and facilities), infrastructure state of degradation, and are interconnected (Figs 4-32 and 4-1). In contrast MBTA has an internal process of project identification (expected through the rolling 5 year Capital Investment Plan) that sets priorities on important reliability and frequency of service improvements (many of these projects have been of upgrading vehicle fleet and signaling system). Each approved project is rated according to an artificial distinction between state of good repair and expansion of the network/services. This review shows that there is too much attention focused on small individual projects and much less on larger strategies to improve the whole system. A more strategic view is needed to address current bottlenecks in the Red Line, by integrating smaller projects into a single processes when planning for rail corridor improvements. This thesis has identified and focused on the South Boston rail corridor where there are many structural bottlenecks in the Red Line (due to problems of branching of the Red Line, and congestion at Columbia junction). Along this South rail corridor the Commuter rail is constrained by single track

171 operations that restrict service frequency on 3 rail lines (with additional South Coast Rail extension services relying on its single track utilization). Double tracking will contribute to current network needs [37] and will enable the absorption of SCR service when line construction is be completed and the future Regional Rail vision, involving higher frequency services of existing Old Colony lines (to meet future projected demand) [72, 78, 121]. This solution achieves a more convenient JFK/UMass station serving both rail services, and providing a convenient transfer point.

For the South Boston rail corridor (both Red Line and Commuter rail) this thesis proposes a solution (with three different alternatives) that involves double tracking the Commuter rail lines, moving the branch junction for the Red Line south of Savin Hill station and improving passenger accessibility and operations at JFK/UMass station. All three alternatives will achieve frequency, safety and reliability improvements for both rail systems with limited disruption to existing operations. The actual work will involve multiple track re-alignments, renovations of multiple bridges and infrastructures and a complex construction sequence involving construction of precast tunnel boxes (underpass for Braintree branch lines and feeder tracks from Cabot Yard) and some earthworks for track elevations/grade separation.

Key features of the alternatives are as follows:

A. Cabot Yard feeding only the Red Line main tracks (before branch separation). This option minimize the construction timeframe through temporary closure of the Commuter rail (north of Quincy Center).

B. This option include one additional feeder line from Cabot Yard to Braintree OB and IB along with Ashmont IB (each connecting to the branch separate tracks). This involves extension of tunnel underpass construction. The proposed a solution minimizes service interruption but would require a longer construction process. The solution would further reduce train quantity and congestion at Columbia junction, maintaining dispatching operations from Cabot Yard with full Red Line and Commuter rail operations during construction.

C. This option includes two Cabot Yard feeder lines connecting to Braintree IB and OB as well as Ashmont IB and OB (each to their separate tracks). This Alternative involves the most extended construction (of underpass tunnels and create full bypass of Columbia junction feeder track. This achieves maximum reduction on train quantity congestion at Columbia junction, allows regular train services during construction, but represents the longest timeframe.

172 We initially proposed Alternative A but were informed by MBTA that feeder lines were important and that closure of Commuter Rail operations would be unacceptable. Alternative B responds to these concerns. MBTA then requested more flexibility in feeder track for dispatching trains from Cabot Yard connecting to the branch tracks at Columbia junction. Alternative C responds to this additional request.

6.2 Conclusions

Considering the constraints affecting renovation or expansion at legacy rail systems and account- ing for all the challenges to large construction project execution, we found capital projects involve many compromises to meet the constraints imposed by different stakeholders (including a long in house review process). One advantage of academic research is that we can take a longer view, not constrained by day-to-day problems. There is already long history associated with the South Boston rail corridor. Recent studies have linked changes to major renovations of I-93 (which have been shelved so far), while the June 2019 derailment at Columbia Junction [4, 22] has resulted in expensive remedial actions to fix the damages caused. The signaling system is currently be- ing upgraded (as part of the current CIP), less than half a year after derailment damages were fixed [10, 89, 94]) but there is no planned projects to address longer-term constraints andbottle- necks associated with the current South Boston corridor. All three proposed alternatives in this thesis show the viability of different track configurations and infrastructures that will improve Red Line operations and concurrently support transformation of Commuter Rail into a more frequent Regional Rail service. We have also identified other projects (notably at Alewife) that could also have an impact on Red Line operation, supporting further improvements and potential avenues for future rail expansion.

6.3 Recommendations

The thesis presents a preliminary design to show the feasibility of improving rail services in the South Boston corridor, focusing mostly on construction of track alignment while keeping con- struction and design binding constraints. We would recommend further review of this proposal

173 (e.g. incorporating Alternative C that meets operational requirements of MBTA), within the South Coast rail project to ensure timely implementation of the project. When current major Red Line improvements and SCR project would be completed the spatial constraints of the MBTA right-of-way and changes to operation would only create more difficulty to construct the proposed Alternatives. Considering that some of the future challenges and projects in this area include the modifications to the Cabot Yard to achieve a state of good repair, and improve its climate resilience (due to susceptibility to be flood from sea level rise) it reinforces the desirability of constructing the modifications in rail configuration in south Boston in the immediate future.

Further studies (in progress) aim to quantify impacts of proposed changes on Red Line headway (through simulations of train operation), while more detailed studies are needed for estimating costs, detailing the construction staging and estimating impacts (on speed codes, line closures etc.).

Bottlenecks associated with Red Line termini and the current multiple challenges associated with use of Cabot Yard (the only maintenance and storage facility) suggest that future work should assess possible need to temporarily or permanently shifting some functions to Codman Yard, or introduce additional storage and maintenance at Braintree.

For the Commuter rail, there are clear benefits in the proposed schemes but double tracking also needs to be extended along span C, Fig 5-1, to accommodate future regional rail plans [72], including South Coast rail [66,67,105] and increasing demand for Commuter rail services [37,78]. Span C between Quincy Center and Braintree stations (right before the 3 Old Colony lines split, Fig 5-1), is much more constrained physically (by high retaining walls supporting adjacent roads) and will require configuration changes to adjacent infrastructures to allow full double tracking. While double tracking this full span would be very challenging, the creation of track pocket bypasses are possible and a further study would be able to quantify their impacts on operations. While the South Boston corridor poses many challenges and constraints for construction and its feasibility, once the Commuter rail lines separate near Braintree, double tracking presents a much easier project to execute (time-frame, easy construction access, wide owned right-of-way, very few grade-separating infrastructures requiring change etc.) a further study, followed by incorporating it within South Coast Rail, and / or a Regional Rail pilot could yield a combined benefit.

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