Three train companies in the south of England have been told they can continue running 40-year-old rolling stock with slam doors for another year.
Some slam-door trains were first introduced in the 1960s
The trains were due to be taken out of service by December 2004 but South West Trains, Southern and South Eastern said they could not meet that deadline.
Now the Health and Safety Executive ( HSE) has given permission to carry on using them until November 2005.
The companies say they have power and reliability problems with new trains.
The train companies agreed to withdraw the old Mark 1 stock in 1999 because of concerns over the doors and lack of protection during a crash.
In granting the extension, the HSE says the introduction of new warning systems since the Ladbroke Grove and Southall crashes means the risk of a collision is greatly reduced and the number of people who fall from train doors has fallen dramatically.
Its figures show deaths from people falling from a moving train have declined from a high of 26 in 1987 to one in 2003/2004.
The decision to grant permission was condemned by Richard Swain, from Staplehurst, Kent, whose daughter Joanne died in 2002 when she fell on to tracks at Paddock Wood.
"My fear is that it will cost lives," he told BBC Radio Kent.
"If they had had electric doors my daughter would still be alive now."
Rail operators say they hope to beat next year's deadline and replace the old trains by the summer.