Customer Challenge

A rail operator needed us to look at creating an electrical wiring interconnection system (EWIS) that standardised the approach across the fleet they were building. As wiring is flexible, it often comes later in the design and manufacture process. This means the cable tray, layout and harness routing solution we worked on with the client had to ensure safety whilst also taking into account the pre-existing design of the vehicle.


  • To design a cable tray to support the main roof harnesses, which stretch longitudinally throughout the car
  • To mount the cable tray to the roof
  • Ensure the design routed harnesses


  • The small car size meant the total solution had to be compact.
  • Because of the sophisticated design of the cars the solution was being fitted to, there was more equipment feeding into a more complex wiring setup than there would be on other comparable rolling stock.


  • As part of the project, we were able to provide a full 3D assembly to allow the client to see exactly how the proposed solution would work.


  • Understand design requirements
  1. EMC requirement to keep each harness separate
  2. Free lifting legs to be fitted in the cable tray
  3. That the size of cable tray lifting jigs be of a particular size
  4. The size of the cable tray remains standard throughout all applications
  5. Cables should not be left sagging – that they be arrested for at respective intervals
  6. Cables should not crisscross
  7. Cables should be protected from getting in contact with the sharp edges of the tray
  • Study and understand the list of equipment the trays would need to support
  • Develop various concepts and layouts for the client


  • Harness are routed between electrical equipment's and LMA, LMM/A.
  • All harness achieved respective standard bend radius.