British Rail's Class 370 tilting trains, also referred to as APT-P (meaning Advanced Passenger Train Prototype), were the pre-production Advanced Passenger Train units. Unlike the earlier experimental gas-turbine APT-E unit, these units were powered by 25kV AC overhead electrification and were used on the West Coast Main Line between London Euston and Glasgow Central. The APT-P is the most powerful domestic train to have operated in Britain, the eight traction motors fitted to the two central Motor Cars giving a total output of 8,000 hp. This enabled the train to set the UK rail speed record of 162.2 mph in December 1979, a record that stood for 23 years.