Inquests into the deaths of four of the 30 bodies already discovered have also been scheduled for Friday.

Coroner Dr Paul Knapman is likely to name a number of the dead - although the grim process of finding and identifying all the bodies could take weeks.

The BBC's Bob Sinkinson: "Unclaimed cars at commuter stations tell their own story"

Deputy Prime Minister John Prescott is to get an interim report on Tuesday's head-on crash by the government-run Health and Safety Executive at about lunchtime.

The HSE will then discuss them at a news conference at about 1400BST, giving early indictions of what may have caused the disaster.

The Financial Times says the report reveals that the advanced train protection system on the Great Western train was switched off when it collided with the local Thames rain.

Though not a factor in the crash, because the Great Western does not appear to have gone through a red light, the news would be embarrassing to the company and raise further questions about safety standards.

The HSE has not commented on the article.

Earlier, about 45 relatives visited the crash scene at Ladbroke Grove, not far from Paddington station.

The group, accompanied by counsellors and clergymen, were escorted to the trackside by British Transport Police officers.

Many carried flowers. One woman wept as she was brought closer to the wreckage.

Superintendent Tony Thompson, of British Transport Police, said: "This will obviously be a very distressing time for them but some relatives feel that it is a necessary part of the grieving process.

"They are convinced that their loved ones have died."

Police say they have managed to whittle down the number of people missing after Tuesday's crash, but the toll could still move past 100.

Of the 30 people still in hospital, four remain critically injured.

Deputy Assistant Commissioner Andy Trotter, of the Metropolitan Police, confirmed 70 missing people had definitely boarded the trains, and he said they were becoming increasingly concerned about the other 57.

Searchers discovered two more bodies in the burned out wreckage on Thursday, bringing the number of confirmed dead to 30.

At a news conference at New Scotland Yard, Dr Knapman said one body had definitely been identified.

BBC News' Simon Montague: Train design to come under scrutiny

He said another three were almost certainly identified and they had a "good idea" of the identity of another 10.

Dr Knapman said various methods were being used to identify bodies: visual likeness, dental records, fingerprints, jewellery, clothes, tattoos or anatomical scars, with DNA being used as a last resort.

He predicted that few, if any, identifiable remains would be recovered from the charred Carriage H on the Great Western express, which collided with a Thames Train near Ladbroke Grove.

Lord Cullen, who visited Tony Blair on Thursday, will head a public inquiry

But he said in those circumstances where he was satisfied someone had died, although no body had been recovered, he could apply to the home secretary, who would issue an order giving him permission to declare someone dead and carry out an inquest.

The search is expected to continue over the weekend and rail services may not be restored until the middle of next week.

The Bishop of Reading: Everyone here knows someone in the crash

Temperatures hit 1000C as fire swept through the first class Carriage H, in what has already become the worst rail accident in the UK for more than 30 years.

Rescuers have to assemble a 100-tonne crane capable of moving and stabilising Carriage H before a fingertip search can begin. The crane, which can lift up to 1,000 tonnes, is not expected to be in operation until Friday.

Mr Prescott has ordered one of the country's top judges, Lord Cullen, to head a public inquiry into the disaster.

John Cartledge of London Regional Passengers Committee: "It's a fiendishly difficult issue"

Speaking on BBC Radio 4's Today programme, he promised to find the money - up to �1bn - to fund the Automatic Train Protection (ATP) system if Lord Cullen's inquiry deemed it necessary.

This summer the government opted for a Train Protection Warning System (TPWS) - a cheaper version of ATP - to be introduced on all trains by the end of 2003, at a cost of about �150m.

Click here to see the site of the crash

The police are trying to end the confusion over the number of people killed and have urged anyone who made it home safely to contact them.

Unclaimed cars in Reading station car park hint at the town's loss

Police in Reading are concentrating their enquiries on 22 unclaimed cars which have been in the station car park for two nights.

They have also appealed to anyone who was on either of the trains and are especially keen to talk to anyone who was in Carriage H but disembarked at Reading.

The number to call is 0171 834 7777. Worried relatives and friends should call the same number.

All people on the train or witnesses nearby are also asked to call the British Transport Police answerphone on 0800 405040 and leave their name and numbers so they can be contacted as part of the inquiry.

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