LCRT Low-Clearance Rapid Transit
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Generalized Feasibility Study LCRT (Low-Clearance Rapid Transit) Harald Buschbacher LCRT Low-clearance Rapid Transit Fast, reliable high-performance urban transport at moderate costs for the city budget Generalized Feasibility Study Generalized Feasibility Study LCRT (Low-Clearance Rapid Transit) Contents 1. Introduction and Initial Situation ............................................................................. 5 1.1. Basic Idea ................................................................................................... 5 1.2. Initial Situation: Average Speed of Different Tram and Metro Models ............................. 5 1.3. Application areas of LCRT ................................................................................ 8 1.4. Task and structure of this study ......................................................................... 9 2. Technical Feasibility and track / road geometry parameters ............................................ 9 2.1. Height difference between LCRT line and crossroad ................................................. 9 2.1.1 Inner height .......................................................................................... 10 2.1.2 Roof thickness and height of rooftop equipment ............................................... 10 2.1.3 Catenary height including electrical clearance ................................................. 10 2.1.3.1 Main variant with two pantographs at the vehicle’s ends ................................ 10 2.1.3.2 Alternative solutions ........................................................................... 10 2.1.4 Floor height according to applied running gear technology ................................... 12 2.1.4.1 Main variant ..................................................................................... 12 2.1.4.2 Alternative solution with running portal wheelsets ....................................... 13 2.1.4.3 Alternative solution with lateral aisles around running gear ............................ 13 2.1.5 Thickness of load-bearing structure, crest and road pavement .............................. 16 2.1.6 Thickness of the track structure .................................................................. 17 2.1.7 Summary: total height difference and cross-section of the underpass ...................... 17 2.2. Alignment parameters for the LCRT line .............................................................. 17 2.2.1 Vertical radii on crests and in hollows ........................................................... 17 2.2.1.1 Visibility ......................................................................................... 17 2.2.1.2 Vertical acceleration and ride comfort ..................................................... 18 2.2.1.3 Inclination change rate and stability for standees ........................................ 19 2.2.1.4 Vertical radii according to design speed .................................................... 20 2.2.2 Longitudinal slope ................................................................................... 20 2.2.3 Horizontal curve radii, superelevation and achievable speed ................................ 20 2.2.3.1 Excursus: Relevance of top speed and speed restrictions for total travel time ...... 26 2.3. Geometry parameters for crossing roads .............................................................. 28 2.3.1 Longitudinal and cross slopes ...................................................................... 28 2.3.1.1 Wheelchair accessibility ...................................................................... 28 2.3.1.2 Current regulation for road geometry ...................................................... 28 Generalized Feasibility Study LCRT (Low-Clearance Rapid Transit) 2.3.1.3 Considerations about safe and smooth traffic flow ....................................... 28 2.3.1.4 Comparative measurements .................................................................. 28 2.3.1.5 Slope parameters for the LCRT concept .................................................... 29 2.3.2 Vertical radii on crests and in hollows ........................................................... 29 2.3.2.1 Visibility on the crest .......................................................................... 29 2.3.2.2 Vertical acceleration .......................................................................... 29 2.3.2.3 Ground clearance on the crest ............................................................... 30 2.3.2.4 Comparative measurements .................................................................. 30 2.3.2.5 Vertical radius in the hollow ................................................................. 30 2.3.3 Elevation of traffic areas against the surrounding level ....................................... 30 2.3.3.1 Possible effect on cityscape and neighbouring buildings ................................. 30 2.3.3.2 Real examples of height and width in public space ....................................... 31 2.3.3.3 Limit values of elevation angle for the LCRT concept .................................... 36 2.3.3.4 Feasible elevation depending on available public space ................................. 36 2.4. Trench depth of pipes and cables below the road surface ......................................... 38 2.5. Standard dimensions of LCRT underpasses ............................................................ 39 2.5.1 Shallow underpass ................................................................................... 41 2.5.2 Deep underpass ...................................................................................... 44 2.5.3 Underpass with hairpin curve ...................................................................... 46 2.5.4 Completely sunken underpass ..................................................................... 47 2.6. Detailed considerations about traffic routing ........................................................ 47 2.6.1 Bidirectional traffic on both sides of the LCRT line ............................................ 47 2.6.2 Traffic signal cycle in case of missing turning lanes ........................................... 47 2.6.3 Application of roundabouts ........................................................................ 48 2.7. Level crossings for pedestrians and cyclists .......................................................... 48 2.8. Barrier effects on pedestrian flow and possible special solutions to overcome them .......... 51 2.8.1 Barrier effect of the standard solution ........................................................... 51 2.8.1 LCRT line without fences (in at-grade sections) ................................................ 52 2.8.2 Mechanical crossing aid (special design elevator) .............................................. 52 2.8.3 Retractable fences .................................................................................. 54 2.8.4 Shallow cut-&-cover construction with direct platform access ............................... 57 2.9. Effects of LCRT underpasses on the cityscape ........................................................ 57 2.10. Possible division of the street cross-section depending on its width ........................... 60 Generalized Feasibility Study LCRT (Low-Clearance Rapid Transit) 2.10.1 Street cross-sections for maximum use of the road width as traffic area .................. 60 2.10.2 Special aspects of LCRT lines in streets with vegetation ...................................... 66 3. Cost estimation ................................................................................................. 67 3.1. Preamble ................................................................................................... 67 3.2. Infractructure construction costs ....................................................................... 68 3.2.1 Methodology and input data ....................................................................... 68 3.2.1.1 Calculation scenarios .......................................................................... 68 3.2.1.2 Indexation and currency conversion ......................................................... 68 3.2.1.3 Costs for conventional tram and metro lines as cost base and for comparison ....... 68 3.2.1.4 Additional costs: Analogy calculation ....................................................... 71 3.2.1.5 Additional costs: compontents calculation ................................................. 72 3.2.1.6 Additional costs: Pedestrian overpasses, fences & compensations ..................... 75 3.2.2 Results ................................................................................................ 76 3.3. Vehicle costs ............................................................................................... 77 4. Costs and achievable speed depending on the surrounding urban structure .......................... 78 5. Further alternatives and design considerations ............................................................ 83 5.1. Rubber-tyred version ..................................................................................... 83 5.1.1 Minimization of pavement stress .................................................................. 83 5.1.2 Variants of radial adjustment of non-driven wheels ........................................... 86 5.1.3 Modified position of the guiding rail .............................................................. 87 5.1.4 Advantages and disadvantages of the rubber tyred version ..................................