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.