Try reading about the following:
1. 11th October 1984 - Wembley Central rail crash, 11 October 1984 3 killed, 18 injured: collision: signal passed at danger; driver's mental state incapacitated by medical condition occurring.
2. 4th December 1984 - Eccles rail crash (1984), 4 December 1984; 3 killed, 68 injured: Inattention by driver; signal passed at danger, rear-end collision
3. 19 September 1986 - Colwich rail crash, 19 September 1986; 1 killed 60 injured: head-on collision at converging route: driver failed to read a notification regarding recent signalling changes; misread signals[47]
4. 4th August 1990 - Stafford rail crash (1990), 4 August 1990; 1 killed, 35 injured: train passed signal at danger, rear-end collision: drunk driver, allegations excessive working hours.
And there is many more that can be attributed to driver fatigue where they are tired or the drivers fell asleep even if only for a moment, where the Drivers Safety Device should have kicked in and stopped the train, thus preventing the accident from happening.