I don't think it's anywhere near 50% that is wasted, since if I understand correctly the resistors are used only during initial acceleration. But anyway, the a

I don't think it's anywhere near 50% that is wasted, since if I understand correctly the resistors are used only during initial acceleration. But anyway, the affected trains are the oldest in use in Britain, from 1972 (Bakerloo Line, 36 trains) and 1973 (Piccadilly Line, 87 trains), out of 620 passenger trains across the whole system. New trains have been ordered and should be introduced in 2025. There's been a 10 year delay, due in part to the 1990s attempt to privatize chunks of the system.