By Rebecca Pike BBC News transport reporter

Transport Secretary Stephen Byers has proposed big improvements to the rail network maintenance. But will his plans make any difference?

This is not the first time maintenance on the railways has come under scrutiny.

In his report into the Ladbroke Grove disaster, Lord Cullen said closer supervision of contractors was a priority.

But his recommendations have yet to be implemented - it's an indication of just how complex the problem has become.

Byers said contracts should not be awarded on cost

Some, like the former senior BR operating officer Peter Rayner, believe that the use of private contractors in itself is bound to compromise safety.

He said: "They don't share experience with each other, they are competing with each other, they are cutting corners, they are subcontracting, they are doing all sorts of things that break up a feeling of corporate wholeness which is part of the safety ethic."

But the government has always said that the current structure will remain in place.

Railtrack's successor will no longer have to give profits to shareholders - but responsibility for the trains and the track will still lie with different companies.

The real problem is that Railtrack itself needs engineers

Gwyneth Dunwoody Commons Transport Select Committee

And contractors will continue to be used.

Mr Byers said that in future, contracts should be awarded on the basis of best value and safety, not simply on low cost. And they should be longer.

But Gwyneth Dunwoody, chairman of the Commons Transport Select Committee, says it won't necessarily improve performance.

'Questions remain'

"The real problem is that Railtrack itself needs engineers, it needs people in-house who can actually check what is being done in their name, and to do that they�ve got to reinstate an engineering culture.

"They've got to reinstate engineers and they've got to make sure that they themselves know what is happening."

Railtrack has made a commitment to train more engineers and get more involved in overseeing maintenance work by contractors.

But questions will remain about whether it gets to the root of the problem.