The client needed to clearly mark the train coach carriages on their 158 fleet with a letter. This is so that those passengers with seat reservations can easily find their designated seat.
When the train travels in one direction, Coach A is at the front.
However, if the trains were to return in the opposite direction, the front coach would be “D”.
The client wished a sturdy device that would enable staff to easily change the coach letter when the train is reversed:
We worked together to design such a device. The outside dimensions were determined by the location of the device. The inner workings had to be as light as possible using materials able to meet the stringent Fire Standards via GM/RT 1234 (since then, EN45545 is the current standard). When the rail key is inserted into the device, it can be used to swap the letters. 2 Prototypes were produced before the design was put into Production.
The device was put into service in August 2011.
The original train coach indicator design was modified and improved in 2017 for a similar part for another customer. Size constraints meant that a complete re-design of the inner workings were required. Furthermore, where the key-hole parts were previously glued, these were re-designed to include a screw, making them sturdier.