The Wembley Central rail crash occurred on 11 October 1984 just outside Wembley Central railway station, Greater London

Greater London

Greater London is the top-level administrative division of England covering London. It was created in 1965 and spans the City of London, including Middle Temple and Inner Temple, and the 32 London boroughs. This territory is coterminate with the London Government Office Region and the London...

.

The 17:54 passenger train from Euston to Bletchley, formed by two Class 310

British Rail Class 310

The British Rail Class 310 is a slam-door, alternating current electric multiple unit introduced in 1963 as part of the West Coast Main Line electrification project. They were initially classified as Class AM10 units before the introduction of the TOPS classification system. Constructed at BR's...

 electric multiple unit

Electric multiple unit

An electric multiple unit or EMU is a multiple unit train consisting of self-propelled carriages, using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages...

s, collided with a Freightliner train which was leaving Willesden

Willesden

Willesden is an area in North West London which forms part of the London Borough of Brent. It is situated 5 miles north west of Charing Cross...

 yard. The first two coaches of the passenger train overturned onto their sides and three passengers were killed; 17 passengers and the driver were injured.

The passenger train had passed a signal at 'danger'

Signal passed at danger

A Signal passed at danger , in British railway terminology, occurs when a train passes a stop signal without authority to do so. It is a term primarily used within the British Railway Industry, although it can be applied worldwide.-Categories of SPAD:...

 after the driver had suffered a transient episode of amnesia

Amnesia

Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...

, brought about by a rare medical condition. As a result, he had cancelled the AWS

Automatic Warning System

The Automatic Warning System is a form of limited cab signalling and train protection system introduced in 1956 in the United Kingdom to help train drivers observe and obey signals. It was based on a 1930 system developed by Alfred Ernest Hudd and marketed as the "Strowger-Hudd" system...

warnings at the signals approaching Wembley without realising.