Automating the visual inspection of rolling stock components at depots offers significant improvements to vehicle maintenance and its scheduling by helping to identify equipment degradation and significant fleet trends.
DeltaRail’s VIEW system offers a range of automatic procedures for the measurement of under-vehicle components such as brake blocks, wheel profiles and current collector shoes – all examined at depot speed. The system can be installed either in the service hall – usually at the end of the inspection pit – or at an exterior location that captures the maximum number of vehicles at the greatest frequency, such as the entry/exit to the depot.
Gathering the data
A typical installation comprises a combination of camera and laser equipment mounted beneath the track. As each train passes over, the leading wheelset triggers an advanced wheel sensor that initialises the system. The axles cause further sensors to activate image capture of the brake pads and wheel profiles, along with vehicle identification information by means of tags or image recognition. This is all stored on a trackside computer and processed to determine key parameters for each target component. This process continues as the train passes slowly over the site until all the images have been collected.
The measurements are downloaded automatically to the Information Display System (IDS) for analysis and trending. This includes the calculation of wear rates, predictions of component life, statistical reports on their history and the identification of components that no longer meet required standards. The IDS allows a user to view the measurement and wear rates of individual components to identify those that need attention and confirm the performance of components across vehicles, units and entire fleets. Information sheets for each vehicle can be generated and the data integrated into the depot management system to generate work cards and assist the management of stores.
Cost and performance advantages
This approach brings many benefits. Both labour costs and turnaround times for inspections are reduced, bringing increased throughputs to existing depots and potentially smaller new-build sites. It can also preclude the need for inspection pits when vehicles are deployed with low floor-to-rail clearance.
Material cost savings of 20% are possible thanks to the reduced component usage that results for better trending and lower scrap limits. Basing maintenance decisions on accurate assessments of wheel, brake and shoe conditions – rather than subjective manual examinations – can allow fixed service intervals to be extended and some overhauls eliminated altogether.
The system brings with it the ability to achieve a higher inspection frequency across the fleet. For example, by ensuring that all braking components are working at an optimal level, the duty on individual wheelset components is more balanced, reducing the potential for accelerated degradation. Demonstrating performance against standards is assisted by the production of accurate statistical reports on fleet condition, enabling users to both maximise component life and flag up emerging issues at an early stage. This brings obvious safety benefits.
A typical VIEW system consists of two lasers and a number of cameras, measuring wheel profile, brake blocks and collector shoes. The equipment consists of –
•       TreadVIEW, PadVIEW, BlockVIEW and ShoeVIEW hardware
•       a trackside PC
•       wheel sensors
•       a visual automatic vehicle identification system.
Component roles
TreadVIEW has a laser for each rail that momentarily scans a segment of the passing wheels. Each laser has an associated camera to capture an image of the illuminated profile. The trackside computer then reconstructs the wheel profile segment.
The BlockVIEW hardware consists of two cameras and associated flash guns to capture images of both brake blocks on a passing axle. Software on the trackside computer identifies specific features of the block surroundings, so calculating the block thickness.
The ShoeVIEW hardware has cameras and flashes to take images of both positive and negative pick-up shoes. The PC is programmed to identify specific features of the shoe gear, enabling it to calculate the distances between them.
Chiltern Railways operates a PadVIEW system for measuring brake pad thickness on its Class 165 and Class 168 fleets at Wembley Depot. The system is installed at a wash plant where frequent measurements can be made at low speed. Upgrades are currently being made to extend use of the facility to Mk3 coaching stock.
