How fast in MPH only are trains on the london underground?

Question

top/normal speed- not average please

Answer 1

The A60 cars were built with a top speed of 70 mph, but are restricted by an imposed limit of 50 mph.

Answer 2

The 1995/96 stock, used on the Northern and Jubilee lines respectively, are the newest trains currently in use on the Underground. Officially, their top speed is around 62mph although I was told by a stock specialist that a test train on the Northern Line reached 73mph. However, they have been electronically restricted so they actually run much slower at the moment. The top permitted speed on the Northern Line is 45mph between East Finchley and High Barnet but the trains can only reach that speed in certain places, usually going downhill.

As for the rest of the network, anywhere between 30-50mph seems to be normal line speed.