Center Truck Performance on Low-Floor Light Rail Vehicles (2006) / Chapter Skim
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Appendix A - TCRP Research Project C-16 Scope of Work
Appendix A - TCRP Research Project C-16 Scope of Work
Pages 52-64
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From page 52... ...
• The extent to which the designs of center trucks and vehicle articulation have taken into account the environment within which they will be used, especially conditions that apply on U.S. and Canadian light rail systems.
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From page 53... ...
Some publications covering appropriate areas of theory were identified but, in an area where the key developments are both novel and recent and where commercial secrecy remains, these were not significant except as a means of identifying the key factors. The main exception to this was the work carried on for TCRP Research Project D-7 and reported in TCRP Report 71, Volume 5, which considered performance issues with IRWs.All the literature reviewed is listed in Appendix F, together with a short summary of the content and its value.
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From page 54... ...
In Phase 2, the researchers proposed investigating these divergences in order to establish the optimum combination of parameters to minimize issues. At this stage, the following features appeared critical: • Wheel profile, in relation to rail profile; • Flange angle; • Flange height; • Truck and truck-to-body attachment detail design and tolerances; and • LRV articulation design, including stabilizing links and dampers.
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From page 55... ...
These design modifications included • Articulation roll stiffness, • Pitch damping of articulation, • Different solutions for stabilizing the pitching mode of the body section above the center truck, • Variation in the lateral secondary suspension stiffness, and • Different wheel and rail profiles. These variations, which were easily implemented in the parameterized model, allowed study of the effect of design changes on the behavior of the vehicle.
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From page 56... ...
4 single wheels on 2 rigid cranked axles, pitching stabilized by a spring system Inter-car connection 2 spherical bearings at either end of the central truck, no dampers, roll inhibited by lateral bars at roof level The Kinki NJT LFLRV has a low-floor area in the central part of the vehicle including the center section (C-car) which is therefore equipped with independent rotating wheels.
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From page 57... ...
A table was produced for each of the following issues: • Wheel and rail profiles, • Sharp curves, • Switch and crossing transitions, • Track standard tolerances, • Gauge tolerance on tangent track, • Tangent track between curves, • Parallelism of rails, • Flangeway clearance on special trackwork, and • Track twist. The purpose was not to create comprehensive tables of data but more to identify where any notable discrepancies likely to have an effect on LFLRV operation might exist and allow recommendations to be made where necessary.
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From page 58... ...
of the inter-car articulations MBTA "worst case" S11 KS New Jersey LFLRV - empty Wheel profile with 63° flange angle High speed track High speed track worn MBTA "worst case" S12 KS New Jersey LFLRV – empty Inter-car dampers removed TCRP D-7 reference MBTA "worst case" S13 KS New Jersey LFLRV - empty Inter-car dampers between all cars (2 sets of 2) TCRP D-7 reference MBTA "worst case" S14 KS New Jersey LFLRV – empty Z-link replaced by a pitch stabilizer spring TCRP D-7 reference MBTA "worst case" S15 KS New Jersey LFLRV - empty Wheel profile with 63° flange angle plus inter-car dampers between all cars (2 sets of 2)
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From page 59... ...
Model NJT New Track TCRP Report 71, Volume 5 Reference MBTA worst case Track type Ballasted Ballasted Ballasted , Note A Rail profile 115RE 115RE 115RE, Note A Rail inclination 1:40 1:40 1:40 Track gauge 56.5in 56.5in 56.5in straight, 57.5in curve Where measured 5/8 in below rail head Curve radius 300ft See below 44ft Vertical curve (combined) See below 400ft Spiral length 130ft (2 of)
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From page 60... ...
The maximum forces were obtained for the NJT LFLRV. • The highest peak lateral forces occur in the perturbed zone of the TCRP Report 71, Volume 5, track and again the maximum was found for the NJT LFLRV.
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From page 61... ...
The modeling suggested that only one pair of dampers was required for the NJT LFLRV in order to limit the lateral wheel-rail forces. • The use of wheel profiles with low flange angles (63°)
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From page 62... ...
Vehicle/Condition w32 w41 Type 7/empty S31 none none Type 8/empty S21 none none NJT/empty S11 none none NJT/empty S15 2 (short duration) none NJT/empty S16 none none Type 8/empty S23 none none Type 8/empty S25 none none Vehicle/Condition w32 w41 Type 7/empty 1.4 (short duration)
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From page 63... ...
63 Figure A-7. Simulation Output 1.
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From page 64... ...
Task 9. Development of the Guidance Required to Mitigate Performance Issues A structured workshop took place in Cologne, Germany, at which the European experts in the team addressed both the issues associated with Task 9 and with Task 10.
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