Investigators were focusing on why the train was ordered to stop in the tunnel.

The motorman of the D train reported seeing smoke too heavy to proceed, and trains were ordered to stop.

Special chains or trains could be ordered for other character sets.

The new trains were ordered long before the Government drew up its plans to put some routes out to private tender.

A further 33 trains of 1972 Tube stock were ordered to provide service on the Jubilee Line.

When trains were ordered to slow down during a recent windstorm, he recalled, many reduced their speed to zero.

After some negotiation 15 trains were ordered with an option for a further 13.

The train, carrying 1,200 passengers, had been ordered to make an emergency stop after an electronic sensor detected overheating in a wheel assembly.

Twelve new trains from the Metrovagonmash were ordered and are in service, with additional 35 on order.

The trains were ordered in 1997, with original delivery dates in 2001 and 2002.