avoid the collision. As a contributory factor to the crash, it was found that the signalman, in clearing the express, had disregarded a standing order known as Regulation 4A, governing the safe operation of signals in sections of track where the minimum stopping distance for trains was shorter than the distance between signals. He had given "line clear" for the express train to the preceding signal box before receiving the required clearance from the following signal box. Instead, he should have sent a "blocking back inside home signal" message to Bentley Heath, the preceding signal box, so that the express train could have been slowed in plenty of time by the Bentley Heath distant signal at caution. However, it was not determined at the enquiry whether the signalman had cleared the express before or after allowing the conflicting freight movement. This may have been academic if the express had been cleared before the freight train was permitted to foul the up main line, even if Regulation 4A had been obeyed. The express train was normally formed by a Blue Pullman multiple unit, an experimental type of new luxury train built for pullman services, but this regular train had to be taken out of service and replaced by the stand-by diesel hydraulic. One of the drivers killed in the accident was Ernie Morris, one of the first drivers to be certified on the Blue Pullman sets, and who had featured in the 1962 British Transport Film "Lets Go To Birmingham", a driver's eye view of the Blue Pullman sets on a run from London Paddington to Birmingham Snow Hill. Two drivers were required on this working and the other driver killed was Sid Bench. The second man, also killed, was David Corkery who was only on the train to cover for the rostered man who had gone sick. David left a widow and two young children. See also List of rail accidents in the United Kingdom References External links Accident at Knowle & Dorridge on 15 August 1963, Railways Archive.co.uk Railway accidents and incidents in the West Midlands (county) Railway accidents and incidents in Warwickshire Railway accidents in 1963 1963 disasters in the United Kingdom 1963 in England 20th century in Warwickshire Accidents and incidents involving British Rail August 1963 events in the United Kingdom Railway accidents caused by signaller's error