The Wikipedia article of the day for August 3, 2021 is Moorgate tube crash.
The Moorgate tube crash occurred on 28 February 1975 on the London Underground’s Northern City Line; 43 people died and 74 were injured after a train failed to stop at the line’s southern terminus, Moorgate station, and crashed into its end wall. It is the worst peacetime accident on the London Underground. The crash forced the first carriage into the roof of the tunnel; the second carriage collapsed at the front as it collided with the first, and the third rode over the rear of the second. The brakes were not applied and the dead man’s handle was still depressed when the train crashed. The inquiry by the Department of the Environment found no fault with the train and concluded that the accident was caused by Leslie Newson, the 56-year-old driver. The post-mortem on Newson showed no medical reason to explain the crash, and a cause has never been established. After the crash, London Underground introduced a new safety system that automatically stops a train that is travelling too fast.