WSPER Rig used to test the wheel slide protection systems fitted onto the B92 and B2007 Docklands Light Rail vehicles.

Derby, march 2020

Background

Docklands Light Railway Ltd. (DLRL) wanted to use DB ESG’s brake technology expertise and their Wheel Slide Protection Evaluation Rig (WSPER) to test the Wheel Slide Protection (WSP) systems fitted onto their B92 and B2007 fleets. The aim was to improve the vehicles performance in low adhesion conditions, to help inform the design of future DLRL fleets and to assist with the planning and implementation of future signalling system upgrades.

Due to high utilisation of the network, access to the track for making an evalution of the WSP performance was extremely limited and thus the DB ESG WSPER facility offered a logical and effective substitute.
To enable testing for DLRL, changes needed to be made to both the WSPER hardware and software to allow additional modelling functionality for the articulated DLRL trains, including electro-dynamic (ED) brake testing.
The brake system equipment on the B2007 and B92 fleets differ in terms of supplier and the way it operates. Testing needed to be conducted to compare the performance of the B2007 fleet, across a range of adhesion conditions, against the older B92 vehicles. Service problems had been experienced with the B2007 fleet and so testing also needed to recreate some of these operational conditions.

Work Undertaken by DB ESG

• Designed and manufactured three new rig modules capable of interfacing with both the WSPER multiple car computers and the WSP equipment (one rig module per bogie). The rig modules comprised of dummy brake cylinders, WSP dump valve mounts, pressure control devices, control valves for application of air pressure and exhausting of residual air pressure, electrical interface boxes and isolating valves.
• Created new WSPER software to represent the weight transfer influence of an articulated bogie and an emulation of eletrodynamic braking behaviour for each fleet type.
• Conducted limited track testing on the DLRL infrastructure using the B2007 and B92 vehicles to capture instrumented measurements of a range of track conditions to support calibration of the WSPER DLR train models. The testing confirmed that the WSPER simulation adequately represented the DLRL system (different to mainline rolling stock).
  
  The track testing consisted of three phases:
  1. Preparation and specification of testing
  2. Vehicle instrumentation and Testing
  3. Analysis and reporting

DB ESG used a combination  of dry rail and detergent based testing. The dry rail and low adhesion testing was used to calibrate the overall braking behaviour of WSPER models representing the B92 and B2007 vehicles. 

• WSPER calibration and simulation testing was then conducted to evaluate the WSP performance.
  
  - The track test data was used to support the WSPER calibration for the B92/B2007 applications.
  - Dry rail testing was conducted to verify friction only, and friction and ED  brake modes. These tests calibrated the brake system characteristics, confirming that the WSPER dry rail braking distances and accelerated profiles correlated with the measured/calculated values.
  -Low adhesion testing was conducted in friction only, and friction and ED modes to calibrate the low adhesion conditioning factors on WSPER.
  -WSPER tests were conducted on each vehicle type.
  -A WSPER report was produced.

Results
The WSPER testing outcome report recommended several improvements for the B2007 vehicles, which are currently being implemented. These improvements will lead to better performance in low adhesion conditions and will also make a small energy saving on a portion of the fleet.