The folder contains c 20 tracing paper, acetate and paper drawings of vacuum interrupters, resistors, isolating valves, fuse panels for Nigerian Railway, Northern Ireland Railway, East African Railways & Harbours, Danish State Railways and British Rail Southern Region. The folder also contains wiring diagrams for dc chopper locomotive (conversion of National Coal Board locomotive type EM2-B1). Drawing number T.C.D. 69.
- Railways, Manufacturing and Transport Engineering, Industry, Electrical Equipment Manufacture, Locomotives and Exports