Lab 6 Prometheus was a test coach that was used by the research & development department of British rail and was converted from a Mk1 BSK by Swindon works in 1975. It’s early years were spent testing pantographs and it was usually attached to the back of service trains on the WCML. This coach is also associated with the testing of the third generation electric locos classes 89, 90, 91. BT10 bogies were fitted and allowed the vehicle to travel up to 125 mph.

The model was converted from a Mainline Mk1 BSK and rides on a set of BT10 bogies from a Hornby Mk3 coach. At one end a window was plated over and a set of grills fitted to the generator compartment. The underframe was also modified with repositioned battery boxes.