Center Truck Performance on Low-Floor Light Rail Vehicles (2006) / Chapter Skim
Currently Skimming:
Pages 35-48
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 35... ...
This guidance is confined to measures identified in this research as a means of mitigating specific performance issues (i.e., derailment, wheel and rail wear, noise and poor ride)
|
From page 36... ...
These can cause any LRV to derail, but the specific type of LFLRV covered by the guidance is more vulnerable. 4.2.2 Wheel and Rail Wear The main causes of wear, associated with this type of vehicle, are • High guiding forces caused by poor steering capability, • Constant flange contact on straight track caused by lack of self-centering capability, • Incompatible wheel and rail profiles, and • Misaligned track.
|
From page 37... ...
The center section is mounted on its own truck, the "center truck," which is an unpowered trailer truck. The end sections are mounted on individually powered trucks, but part of their mass is also carried by the center truck via the articulations.
|
From page 38... ...
The design must not generate excessive lateral forces between the wheel and rail and must 38 Profile feature Influences Tread slope and shape Ride, guidance, wear, and noise Flange angle Derailment protection, passage through S&C Toe radius Switch safety Toe shape Flange running ability Flange height Derailment/depth of grooves Blend radius Guard rail effectiveness Flange root radius Flange wear (especially on IRW) Flange thickness Toe radius/blend radius, wear allowance.
|
From page 39... ...
with flange tip running, 20 mm (0.8 inches) otherwise Section 3.6.2 Flange angle To suit rail profile and similar to other cars that will continue in use on the system 72o minimum.
|
From page 40... ...
The main stages, in relation to the issues described in Section 4.4, will be • A visual check to see that the vehicle has all the features expected and that they are correctly assembled; • A static measurement check, including use of wheel profile measuring gauges; • A static loading test to check that the suspension characteristics are as expected; • Dynamic running tests to ensure that the vehicle ride meets the performance requirements under a range of loading conditions, including noise measurements both inside and outside of the vehicle; and • Checks on the condition of the wheel running surface and on the track at vulnerable locations (e.g., sharp curves and switches) to ensure that excessive wear is not occurring.
|
From page 41... ...
The manuals only need be provided where the suppliers are not carrying out maintenance; this applies to components as well as vehicles as a whole. So for example if the center trucks are to be maintained by the supplier, the manual should only cover how they are removed, replaced, and tested.
|
From page 42... ...
Section 3.6.1 Wheel wear on tread before scrapping Depends on wheel and rail profiles Wheel wear on flange before scrapping Depends on wheel and rail profiles Wheel gauge +0.04 inches (+1 mm) Wheel taper +0.5o Flange height Minimum 0.75 inches (18 mm)
|
From page 43... ...
. 4.9.5 Switches and Crossings One of the main objectives of specifying features of switches and crossings when LFLRVs are operated is to minimize derailment risks associated with IRWs on the types of center truck used.
|
From page 44... ...
Switch rail tip design Adapt to suit vehicles Design to avoid flange angle issues Fully guarded switches Provide if necessary at vulnerable locations Avoid need by good overall system design House tops Provide if necessary at vulnerable locations Avoid need by good overall system design Flangeway As constant as possible, acting like the plain line situation. Flangeway clearances Minimum 11/2 inches (38 mm)
|
From page 45... ...
The act of creating an infrastructure maintenance manual ensures that the transit authority anticipates issues that might cause issues and manages them. Where the maintainer is not the transit authority, the latter should monitor the process sufficiently so as to ensure that the performance requirements are being met in an optimized way (e.g., the transit system has not observed the guidelines and, as a result, its vehicles are suffering excessive wheel wear)
|
From page 46... ...
Scheduled Preventive Maintenance LFLRV performance will depend partly on maintaining key track parameters within relatively tight tolerances; therefore, these tolerances must be monitored as part of a scheduled preventive maintenance program. The key parameters to be checked include rail profile and alignment, switches and crossings dimensions (including gauge face wear)
|
From page 47... ...
The researchers assume that the basis for the system's maintenance standards are APTA's Standard for Rail Transit Track Inspection and Maintenance, referred to as "APTA" in the table. 4.12 Infrastructure Modification Circumstances can arise where the transit system modifies track.
|
From page 48... ...
. 4.13.4 Basic Vehicle Configuration The earlier guidance in this document has assumed the specific type of PLF LRV being studied in this research [i.e., one that has three sections, the center section mounted on a center truck with IRWs (see Section 4.4.3)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.