Old Colony Railroad Rehabilitation Project

Home , Greenbush Line, Old Colony Lines, Old Colony Railroad

By:

Robert J. Frascella, P.E. Project Manager Sverdrup Civil, Inc. Two Center Plaza Boston, MA 02108

Phone: (617) 742-8060 Fax: (617) 74241830

ABSTRACT

OLD COLONY RAILROAD REHABILITATION

Sverdrup Civil, Inc. provided all engineering and construction phase services to the Massachusetts Bay Transportation Authority for the reconstruction of three branch lines of the Old Colony Railroad. The Old Colony Railroad serves 600,000 residents in more than 30 communities in the fastest growing part of the state, helping to relieve severe traffic congestion on area roadways. The Main, Middleborough, and Plymouth Lines of the Old Colony Railroad have been totally reconstructed and now offer direct service to Boston's South Station Intermodal Transportation Center for more than 10,000 inbound riders per day with trip times of under one hour. Restoring service required the design and construction of 99.8 km (62 route miles) of railroad; 488 m (1,600) feet of cut-and-cover tunnels; 15 commuter rail stations; two train layover facilities; a centrally-located maintenance facility; 44 grade crossings; 11 passing sidings; improvements to 18 roadway intersections; a system wide signal and communications system; and the construction or rehabilitation of 47 bridges. The Old Colony Railroad, which maintained rail traffic throughout construction, was designed for joint use by commuter and freight trains. This presentation focuses on the challenging and difficult issues associated with constructing a modern commuter rail transportation system in an urban, suburban, and rural environment.

KEYWORDS: Commuter Rail Railroad Rehabilitation New Service Joint Use Massachusetts

INTRODUCTION

For more than thirty years, Southeastern Massachusetts has been plagued with severe traffic congestion because that region of the State lacked a viable commuting alternative to the passenger automobile. The focus of this presentation is two-fold. First, it will present the history, planning and development of restored commuter rail service to this region. Second, it will highlight some of the engineering challenges that the designers and builders faced in bringing this once thriving railroad back to life.

Since the start of revenue service in September 1997, more than 8,000 automobiles per day have been eliminated from area highways, traffic conditions have greatly improved and air quality has become more acceptable. This has all become possible due to the rehabilitation of the Old Colony Railroad.

HISTORY

The Old Colony Railroad was originally constructed in the mid-nineteenth century to satisfy the transportation needs of eastern Massachusetts. By 1845, rail service on the Old Colony lines had been extended to most of southeastern Massachusetts and portions of Rhode Island- In 1893, the Old Colony Railroad became a part of the New York, New Haven and Hartford Railroad through a lease arrangement. Under New Haven management, The Old Colony lines survived for many years as the primary means for commuters to access Downtown Boston from the southern suburbs.

During the post-World War II years, the Old Colony commuter lines became a financial burden for the New Haven Railroad which sought for many years to abandon the passenger service on the branch lines serving Plymouth, Middleborough and Scituate, MA. Increased use of the passenger automobile and new highway construction meant decreased ridership on the former Old Colony Lines serving the southeast region of the Commonwealth. In 1959, the Commonwealth of Massachusetts completed construction of the Southeast Expressway, a major arterial highway from Boston to Cape Cod. Concurrently, the State railroad subsidy was discontinued. This made automobile access to Boston easier and forced the New Haven Railroad to further reduce service on the Old Colony Lines.

Shortly after the Southeast Expressway opened in 1960, the Old Colony drawbridge across the Neponset River was destroyed by fire. Through train movements were no longer possible between Boston and South Shore communities. Freight service continued uninterrupted on the Old Colony Lines after the bridge was destroyed from existing connections via Attleborough, MA and South Boston. As such, the New Haven had no interest in replacing the damaged structure. Commuter service was permanently halted on the former Old Colony Lines and many Boston commuters were left with few alternatives to the automobile.

In 1984, the Massachusetts Legislature allocated funds to enable the Massachusetts Bay Transportation Authority (MBTA) to study the restoration of commuter rail service to southeastern Massachusetts. A feasibility study was undertaken by Sverdrup Civil, Inc. to determine whether sufficient ridership would support reconstruction of the Middleborough, Plymouth and Greenbush Lines of the Old Colony Railroad. The initial study concluded that ridership would support restoration of commuter rail service in this region. The study recommended a number of alternatives worthy of consideration.

In 1986, the Governor and the State Legislature directed the MBTA to proceed with environmental studies in support of the restoration of the Old Colony Railroad to full commuter rail service. The environmental studies recognized several other benefits to the restoration of commuter rail service. A reduction in vehicles on the area roadways would improve air quality within the region. Also, improved commuter rail service would provide valuable mitigation to the planned Central Artery Project, a major highway construction project currently underway in downtown Boston.

As part of the environmental review process, a Draft and Final Environmental Impact Statement/Report (EIS/R) was prepared for the Main, Middleborough and Plymouth Lines. Following a six-year public review process involving legislators, federal and state agencies, town governments, and the general public, the environmental assessment was completed by the end of March 1992. The Massachusetts Secretary of the Executive Office of Environmental Affairs (EOEA) issued the final state approval in May of 1992.

The Federal Transit Administration (FTA) issued its Record of Decision (ROD) in June of 1992 clearing the way for design and construction of the Middleborough and Plymouth Lines of the Old Colony Railroad. The Greenbush Line was excluded from the ROD because of public opposition in the Town of Hingham with regard to impacts on historic resources. A supplemental EIS/R was prepared separately for the Greenbush Line addressing these issues and preliminary design on this branchline is now underway.

DESIGN OF THE RECONSTRUCTION BEGINS

Immediately following the ROD, the design phase of the Old Colony Rehabilitation began. The project, as conceived, involved the reconstruction of 99.8 Ian (62-route miles) of track; construction of 14 new commuter rail stations; rehabilitation or replacement of 42 bridges; improvements to 54 grade crossings; construction of two train layover facilities; construction of 2.9 Ian (1.8 miles) of track on new alignment; construction of 1,067 m (3,500 ft.) of new double-track tunnel section under a limited access highway and a highway interchange; replacement of the Neponset River drawbridge with a 363 m (1,190 ft.) double-track, fixed-span structure; a maintenance of way facility; a new signal system; and other amenities required to develop a modem, functional passenger transportation system.

An aggressive schedule for design and construction was undertaken. The start of revenue service date was fixed at December 31, 1996. This left four short years to complete design, construction and stall-up activities. In addition, it was decided to divide the construction into several smaller contracts to provide more opportunities for smaller contractors and to allow the construction to be staged to permit early activities to proceed unabated. Long lead items were procured separately by the MBTA for installation by the primary contractors. Such items as rail, crossties, fasteners and turnouts were ordered at an early date to avoid delays during construction. By the time construction was complete, more that thirty construction contracts were awarded to more than 25 different contractors with a total construction cost of $537-Million.

CONSTRUCTION OF THE NEW OLD COLONY RAILROAD

The first 17.7 kin, (11 miles) of the New Old Colony Railroad was constructed immediately adjacent to the MBTA's Red Line rapid transit system. The Red Line system was constructed in the 1970's within the former Old Colony railroad right-of-way. The Red Line designers had the foresight to reserve an additional trackway within the corridor for future transportation purposes. Had this not occurred, rehabilitation of the Old Colony as a commuter rail system would not have been possible. Though this advanced planning facilitated the development of the Old Colony Commuter Railroad, it was not an easy effort. The reserved trackway meant that only a single-track railroad with one passing siding could be developed for the first 11 miles. And, the trackway, which was originally reserved for rapid transit purposes, did not have adequate clearances for commuter rail equipment without significant reconstruction.

The rehabilitated portion of the Old Colony Railroad began just south of Boston's South Station (Milepost 0.0) at Milepost 1.1 at a location known as South Bay. The first major obstacle was encountered at this location. A double-track embankment supporting the Red Line access to Cabot Yard blocked the path to the Old Colony trackway. Cabot Yard is the Red Line's centralized maintenance facility and storage yard. The embankment required a double-track under crossing of the Old Colony alignment on an acute skew angle. Construction at this location was further complicated by the requirement to keep both Red Line tracks in operation during construction except during short outage periods for connection of shoo-fly tracks. The chosen structure was a cast-in-place concrete box section bearing on a grade beam foundation. Due to its close proximity to Boston Harbor, soft soil conditions required that the new structure's foundation to be supported on deep caissons.

At Milepost 2.6, the Old Colony trackway passed beneath the Braintree branch of the Red Line. From this point to Milepost 3.6, the single-track Old Colony trackway was located between the Braintree and Ashmont Branches of the Red Line. The existing track was situated in a narrow corridor that prohibited conventional track construction. In addition, the Old Colony trackway had to be fenced separately from the Red Line on both sides. Track center distances from the nearest Red Line track was as little as 5 m (16'-5") in some places. This meant that a conventional 1.83 m (6-ft.) high fence was not practical in some locations. To satisfy legal clearance requirements, use of a shorter 1.22 m (4 ft.) fence was necessary. Also, to assure track worker safety, refuge niches were provided at all locations where a minimum of 2.6 m. (8'-6") horizontal clearance could not be maintained.

The track construction in this area also prohibited the use of open drainage ditches. To assure positive drainage of the track structure, the use of perforated composite section PVC pipe underdrains was adopted. Underdrains were installed below the subballast section at the edge of the trackway and were subjected to the influence of railroad live loads. The composite pipe section provided a high stiffness factor, a relatively low cost and ease of construction. Track construction in this area was also complicated by the need to relocate Red Line traction power and signal lines from the Old Colony trackway. In addition, new signal and communication lines for the Old Colony system had to be installed in buried conduit beneath the new tracks.

Many sections of the Old Colony Railroad pass through communities where the track is within close proximity to residential structures. The principal concern of abutters was the noise and vibration imposed upon them by the passage of commuter rail trains. To help mitigate these impacts, the MBTA constructed sound barrier walls at impacted locations to satisfy community concerns. In addition, some locations qualified for vibration mitigation through the use of wood ties in lieu of concrete ties and, at severely impacted locations, ballast mats. Noise barrier walls were typically constructed with brick materials in highly visible areas and composite materials where visibility was not a concern. Ballast mats were constructed beneath the track structure upon an asphalt underlay laid directly upon the subgrade. The mats consist of a 0.95 cm (3/8") thick rubber surface supported slightly above the asphalt underlayment on truncated cones molded into the mat. The ballast material was placed above the mat and the air gaps beneath the mat to help attenuate the ground borne vibrations created by the train pass-bys.

At Milepost 5.1, the largest bridge structure on the rehabilitated Old Colony Railroad was erected to span the Neponset River. As mentioned previously, the original Neponset River bridge was destroyed by fire in 1959. Since that time, this river crossing has always presented a major obstacle to the reopening of the Old Colony Railroad. The replacement of this structure was further complicated by the requirement to replace the former drawbridge with a fixed structure. Since the Neponset River was navigable, a 12.2 m (40-ft.) high waterway opening above mean sea level had to be maintained for maritime purposes. On a fixed structure, this meant that steep approach grades had to be constructed on each bank of the river because the alignment passed beneath significant underpasses on either side of the bridge. The profile grade was established with 3 percent approach grades from both directions with a high point established above the navigation channel. The resulting structure was a double-track, multi-span, 363 m (1,190 ft.) long, ballasted deck, steel through plate girder bridge constructed on vertically curved alignment.

Other factors contributed to the complexity of this major river crossing. Since the Old Colony Railroad shares the same corridor as the Red Line, the new Neponset River bridge had to be constructed immediately adjacent to the Red Line's structure across the same river. The Old Colony bridge had to emulate the Red Line structure with regard to pier location, span length and clearance above the navigation channel. This was especially complicated when it came to construction of the piers within the river. Due to the soft clay soil conditions at the river bottom, the piers were founded on steel H-piles driven to bedrock both vertically and on a batter at the perimeter. The piles were driven within a cofferdam which was eventually sealed and dewatered for construction of the pier foundations. The pile driving process was complicated by the fact that the adjacent Red Line bridge piers were also bearing on piles of which the perimeter piles were also battered. The Red Line bridge piles were not founded on bedrock but were merely driven to refusal, as such, the Old Colony piers were potentially pirating bearing capacity from the adjacent structure. Extreme care was exercised during the pile driving process to avoid compromising the stability of the existing structure. It was necessary to maintain regular service on the Red Line at all times during construction. Inclinometer instrumentation was placed on the Red Line bridge to detect any movement on that structure that may have been caused by the adjacent pile driving process. In addition, accurate as-built information showing the location and orientation of piles, available from the Red Line bridge construction, aided the contractor in placement and driving of the battered piles.

Once construction of the piers was complete, erection of the main spans commenced. Placement of the bridge girders was accomplished at night between midnight and 5:00 A.M. when service was not provided on the adjacent Red Line. Each of the 59.9 Mg (66 ton), approximately 36 m (118 ft.) long girders were lifted and positioned from a temporary trestle that the contractor erected from each bank to, not only facilitate erection, but also to simplify construction of the piers and to expedite the pile driving process.

Construction adjacent to the MBTA's Red Line south of the Neponset River presented some unusual challenges. Though the trackway for the Old Colony had existed for many years, it was intended to be used for expansion of the rapid transit system. The clearances and grades within this corridor would not accommodate commuter rail equipment. Many existing overhead bridges and structures would not meet the minimum allowable dimension for commuter rail clearance. This meant that the Old Colony trackway had to be lowered as much as 1.22 m (4 feet) directly adjacent to the Red Line. Retaining walls had to be constructed between the Old Colony Main Line and the Red Line tracks at several locations. Further complicating the matter was the requirement that the Red Line had to remain in operation at all times during construction.

The grade differential wall utilized a soldier pile and lagging embankment support system in conjunction with a cast-in-place cantilevered concrete retaining wall system. Soldier piles were driven from the Old Colony grade and lagging was placed to retain the resulting embankment during construction. Retaining wall construction progressed from the Old Colony side with minimal disruption of Red Line service with the exception of slow orders through the construction zone.

At Milepost 10.5, the Old Colony Main Line divides into the Middleborough and Plymouth Lines. This location is also the site of Braintree Station serving both Old Colony Lines. The station was constructed at the location of a former Conrail freight yard. To construct the Old Colony main tracks and station platform, the freight yard had to be relocated to the western edge of the site. Three new double-ended sidings and a lead track were constructed to facilitate the handling of freight cars at this location and safely separate freight operations from commuter service.

Further south at Milepost 11.5, Pearl Street in Braintree crossed both the Middleborough and Plymouth Lines at grade. Early in the planning phase of the project, it was decided that due to the large number of train pass-bys (54 trains per day) this location would be grade separated. A grade separation at this location was rather complicated for several reasons. First, Pearl Street was situated on a steep grade with the railroad located at the top of the grade. Second, the right-of-way was located in a densely populated suburban setting with major retail shopping centers adjacent to the right-of-way on both sides of Pearl Street. And, third, both roadway and railroad traffic had to be maintained at all times during construction.

After carefully studying the various alternatives, it was decided that an adjustment of both the Pearl Street and Old Colony Railroad grades at this location would provide an effective solution to this difficult grade separation. The plans called for lowering the roadway surface approximately 3.66 in (12 feet) below the existing tracks and raising the railroad profile grade approximately 2.44 in (8 feet) above its former grade.

Because the Middleborough and Plymouth Lines of the Old Colony diverge at this location, it was decided to construct the new crossing on separate structures. This meant that one line could be constructed separately from the other. Because the Middleborough Line was used for daily freight service, it was decided to construct the Middleborough span first while rail traffic was diverted across the lowered roadway grade using a temporary railroad bridge at the location of the proposed Plymouth Line structure. During excavation of the Pearl Street grade, Pearl Street traffic was detoured on a temporary shoo-fly alignment just north of the former grade crossing location. With the Pearl Street traffic temporarily detoured, the final roadway alignment was excavated and a temporary railroad bridge was built above the lowered roadway grade on the shoo-fly alignment.

Once completed, rail traffic was diverted onto the temporary bridge and construction of the new Middleborough Line structure commenced. Because the railroad grade had to be raised by 2.44 m (8 feet), retaining walls were required along the right-of-way limits. The use of mechanically stabilized embankment (MSE) with segmental concrete block facing was chosen in lieu of cast-in-place concrete retaining walls due to its low cost and ease of construction. The tallest MSE wall constructed at this location was in excess of 10.6 m (35-ft.) in vertical height. This was considered to be the only known MSE retaining wall of this height subjected to the surcharge of E-80 railroad loading.

With the temporary railroad bridge in place, roadway traffic was diverted off the detour route and onto the lowered Pearl Street grade. Once the at-grade detour was eliminated, the approaches for the Middleborough Line bridge were completed, bridge girders were set, the new ballasted-deck bridge was completed, the railroad grade was adjusted to its final profile and track was constructed along the Middleborough Line alignment.

With the Middleborough alignment complete and freight traffic diverted to that route, the construction of the Plymouth Line bridge above Pearl Street commenced. First, the temporary railroad bridge had to be removed. Then, new abutments were cast and tied into the adjacent structure. Next, the Plymouth Line bridge was placed above the Pearl Street grade and retaining walls were extended to the final trackway elevation. Finally, all remaining trackwork was completed and connected to the universal crossovers immediately north of the Pearl Street grade separation.

Track construction along the Plymouth and Middleborough Lines typically consisted of 132 RE rail control-cooled, plant-welded secured with Pandrol fasteners. Heat-treated rail was used on all curves greater than two degrees. Ballast consisted of American Railway Engineering and Maintenance-of-Way Association (AREMA) type 4 granite ballast with a minimum thickness of 30.5 cm (twelve inches) placed below the tie. Ballast material was placed on a minimum 20.3 cm (8-inch) layer of low permeability sub-ballast material compacted in place and crowned to promote surface drainage to flow away from the track structure.

Concrete ties were utilized at all locations except where rail borne vibration was considered to be in excess of the established threshold criteria. At those locations, wood ties were installed to help dampen vibration. Approximately 35 locations along the 99.8 kin (62-route miles) of the rehabilitated Old Colony Railroad required wood ties to mitigate vibration created by the passage of commuter rail trains. Approximately 30% of the nearly 250,000 crossties used were wood ties. The minimum length of a wood tie segment was set at 0.40 km (0.25-miles) with a minimum of one mile between segments. This avoided a patchwork of tie materials and facilitated future maintenance considerations with regard to undercutting, surfacing and tie replacement. 'Me running rails were secured to wood ties with Pandrol fasteners attached to tie plates anchored to the ties with lock spikes.

All turnouts were constructed using tropical hardwood switch timbers. These timbers were drilled and turnout components were secured with screw spikes. Rails, frogs and guard rails were attached using Pandrol fasteners. Number 20 turnouts were typically used at all interlocking and crossover locations where a 72.5 kin per hour (45 mile per hour) speed was desired on the diverging route of the turnout. Number 10 turnouts were used for freight sidings, maintenance-of-way sidings, yards, layover facilities and at all locations where low speed movements through turnouts was permissible.

In general, the existing top of rail profile was adjusted vertically upward to eliminate the necessity to dispose of a large quantity of soil material. Environmental considerations, with regard to disposal of railroad subgrade materials versus reuse of that material in place, were also a factor in the decision to avoid hauling soil material off site. Though this reduced costs, the profile grade adjustment created other design issues that had to be mitigated. An average profile grade adjustment of 30.5 to 45.7 cm (12 to 18 inches) was provided along both the Plymouth and Middleborough Lines. This adjustment meant roadway approach grades at all grade crossings had to be altered to accommodate the track grade change. Track grades had to be lowered or set at the original grade at overhead bridge crossings. Fill slopes and embankments had to be extended as the top of the embankment was raised, not only to avoid the disposal of soil materials, but also widened to accommodate the proposed typical section. The latter was particularly difficult to design and construct because of right-of-way constraints and wetlands located adjacent to the trackway.

A variety of retaining wall and slope stabilization methods were used along the right-of-way. Mechanically stabilized embankment (MSE) was used wherever steep slopes were required. In many cases, slopes as steep as 1.5:1 were constructed in natural soils consisting of sand and gravel. Slopes stabilization methods included erosion control mats, loose rock blankets and, wherever possible, natural vegetation.

Vertical retaining walls along the right-of-way included MSE walls with both block and panel facing, soldier pile and lagging walls, precast concrete modular walls, precast concrete T-section cantilever walls, sheet pile tie-back walls, cast-in-place concrete cantilever walls, precast concrete tie-back walls, and granite block walls. The wall type selection was based upon the most practical and economical section available to meet the specific needs of the construction site. Based on a comparison of bid rates for conventional cast-in-place reinforced concrete walls and other types of wall used on the project, it is estimated that the use of alternative types of wall systems saved over $15 million for the project. Because the Old Colony Railroad was rehabilitated through urban and residential areas, aesthetics and historical factors also contributed to the wall type and wall finish characteristics. In some cases, historically significant retaining walls and bridge abutments required rebuilding with like materials, such as, granite block. Where railroad surcharge loads were a factor, these walls were constructed as a facing element on cast-in-place concrete or soldier pile and lagging walls.

At Milepost 33.7 on the Plymouth Line, a new 2.9 km (1.8 mile) long branch line was constructed on new alignment to access the Kingston station and train set layover facility. This double-track section of the Old Colony Railroad involved some rather complicated construction means because the alignment crossed a limited access highway at two locations in a tunnel structure. It also passed beneath a highway interchange and traversed an electric power utility right-of-way to reach the station and layover site.

Massachusetts Highway Route 3 and its intersection with secondary Route 3A were impacted by the Kingston Branch construction. Rt. 3 is a busy arterial highway serving as the primary route between Boston and Cape Cod. Rt. 3A is a busy north-south local arterial roadway serving the local Plymouth and Kingston areas. Traffic could not be interrupted on Route 3, Route 3A nor the partial Rt. 313A clover leaf interchange at anytime during construction. This meant that tunnel construction beneath the highway had to occur with only partial lane shifts along Route 3. In addition, two lanes of traffic in each direction had to be maintained at all times.

The chosen construction method was to build the tunnel from the top down using precast concrete segmental tunnel wall panels inserted in a slurry trench. Slurry trenches were excavated with a clamshell bucket and a bentonite slurry was pumped into the trench to stabilize the trench walls. This method eliminated an otherwise extremely expensive excavation support system and time consuming cast in place construction. Once excavated to the proper depth, the 2.44 m (8 ft.) wide by 53.3 cm (21 inches) thick tongue and groove precast panels were inserted into the excavation as the bentonite slurry was pumped out of the trench.

With both tunnel walls in place, the tunnel roof slab was cast on grade using the former highway subgrade as the bottom of the form. This method progressed across the highway segmentally through four separate lane shifts. Once the roof slab was complete, the tunnel cavity could be excavated from below without interrupting traffic on the roadway above.

Once the tunnel was excavated to the required elevation, a cast-in-place concrete base slab was poured to form the tunnel floor. The floor system included direct fixation (DF) of the track using vibration isolation fasteners. The track was installed by first pouring the base slab with a recess provided for the trackway. Next, the running rails were set at their final profile grade with the fasteners secured in place. The trackway was then cast using a second pour of concrete bringing the trackway slab up to the bottom elevation of each fastener. The DF fasteners not only secured the rails in place through the tunnel's 5-degree curves but provided necessary vibration dampening as the tunnel was located adjacent to a residential area.

The largest of the Old Colony Railroad's commuter stations was situated at the terminus of the Kingston Branch. This station contained more than 1,000 parking spaces with ample space for expansion. The Old Colony stations were intended to be park and ride type facilities. Enclosed station buildings were not provided because the actual time a commuter rail passenger would spend at any given station would be minimal. Weather protection along the platform was provided in the form of canopies and wind screens. It was intended that commuters would await the train's arrival in the comfort of their automobile during inclement weather. Each station was equipped with illuminated train approach warning signs indicating both visually and audibly that a train was within 2 to 3 minutes of arrival. This would allow ample time for passengers to leave their vehicles and walk safely to the platform.

In addition to the train approach warning system, each station contained a scrolling LED message sign and public address system to advise commuters of train status and other system information. These systems enabled each station to become fully compliant with the regulations imposed by the Americans with Disabilities Act (ADA) for visual and audible handicapped persons. Other ADA compliance features included a 244 m (800 ft.) long high-level platform allowing access to the entire train, tactile edge markers, accessible ramps and parking areas, and braille signage.

Some station sites were situated with parking lots located on the opposite side of the main track from the passenger platform. Where this occurred, pedestrian grade crossings were provided. Each crossing was equipped with automatic warning devices including crossing gates, bells and flashing lights activated by approaching trains.

At the terminus of each line, a train set layover facility was provided. Typical operations require inbound commuter trains to depart from the end of the line to cover the morning rush period. Typically, trains are scheduled on 30 minute headways during the rush periods, as such, each layover facility required a minimum of four tracks to store commuter trains a maintenance-of-way siding and one spare equipment track. During the overnight layover period, light maintenance, inspection, and cleaning is performed on each set of rolling stock. To avoid the need for equipment to idle continuously, an electrical sub-station was provided to supply 480-volt electrical power to cars and locomotives stored at the facility.

SERVICE BEGINS

The original target date for start of revenue service of December 31, 1996 was delayed until September of 1997. The MBTA had decided that an enhanced train control system would provide a better safety margin for commuter rail passengers. A cab signal system was added to the signal systems contract to augment the use of wayside signal indication. This would eliminate the possibility of a delayed-in-block signal mishap similar to the accident that had occurred in Sliver Spring, MD in February of 1996.

On September 27, 1997, inaugural Old Colony trains ran on both the Middleborough and Plymouth Lines to an inauguration ceremony held at Boston's South Station. This event marked the beginning of commuter service on the Old Colony Lines after a 38-year hiatus. On the following Monday, September 29, 1997, revenue service to South Station began with 54 regularly scheduled trains in daily weekday service.

The Old Colony Railroad has been a tremendous success for the MBTA in an area of the Commonwealth that desperately needed an alternative to the passenger automobile as a means of commuting to Boston. Ridership, originally expected to be approximately 10,000 one way riders per day for the first year, quickly climbed to 11,500 within a few short months of the start of service. Due to its popularity, the Authority is already exploring the possibility of expanding the Old Colony service to include larger trainsets, expanded parking facilities and more frequent service.

Commuters from Boston's South Shore area now have a comfortable, convenient, reliable, safe, and affordable transportation alternative to facilitate their daily commute to work.