Inside the cab of an APT-P train. This was a prototype high speed tilting train. The APT-P was unveiled to the public on 7 June 1978 and continued to be used for testing into 1986. Due to ongoing technical problems with these pre-production units, and a lack of cash or political will to take the project forward, the planned APT-S (Advanced Passenger Train Squadron Service) production-series units were never built, but did influence the design of the later InterCity 225 sets designed for the East