AMONG the first floral tributes to appear at the scene of the Hatfield rail crash was a bunch of white lilies, accompanied by a card reading: "With sympathy from all the staff at Railtrack."

The simple message is an indication of how the tragedy has stunned an industry still proud of its safety record in comparison with other forms of transport. But with speculation on the cause of the disaster homing in on the possibility of a broken rail, Railtrack must be bracing itself for criticism, not only from the relatives of the dead and the injured but also from other passengers and politicians.

The disaster could not have come at a worse time for the company, in the middle of the inquiry into last year's Ladbroke Grove, Paddington crash. The accident, in which 31 people died, happened during the inquiry into the Southall crash of 1997, when seven people were killed.

Gerald Corbett's decision to offer his resignation yesterday as chief executive of Railtrack seems to be a clear attempt to pre-empt calls for sackings in the wake of Tuesday's derailment. But even critics of the company's record have praised his commitment to improving safety in the three years since he took over at the helm.

"He has made a good start in pushing Railtrack in the direction it needs to go," says Anthony Smith, director of the Rail Passengers Council. "Gerald Corbett has done a lot to drag Railtrack screaming into becoming a modern, effective company.

"But it is only the start of that process and we haven't really seen the results. I think he is premature in offering to resign before we know what happened, but if things were pointing in the direction of the train being at fault instead of the track I don't think he would be resigning."

Railtrack has sought to dampen criticism by drawing attention to the amount of money it is investing in the rail network. The first six months of this financial year have seen the company put £1.2bn into improving the tracks, an increase of 36 per cent on last year, and it is on target to spend £2.5bn over the year.

And the company is committed to spending £52bn on improvements over the next 12 years. Railtrack's London North Eastern division is spending £259m in renewal and enhancement work this year, a 30 per cent increase on the last financial year.

But for a company which until recently was making £1m in profit a day, it is vulnerable to accusations that too little has been put back into safety.

Broken rails have been one of the key targets of the rail regulator Tom Winsor. Since his appointment two years ago, he has cracked the whip in trying to pull the privatised rail companies into line: just two months ago he warned Railtrack over failing to reduce the number of broken rails.

The number of broken rails was reported at 917 in the financial year ending in April and 952 over the previous 12 months, when Railtrack itself forecast a figure of 600. And last year's figure was an increase of 21 per cent on the number of broken rails reported in 1997/8.

The regulator wrote to Mr Corbett in August warning that this appeared to be in breach of the company's operating licence, requiring the company to maintain the network in accordance with best practice. Mr Winsor went on to say that he was appointing independent specialist consultants to advise Railtrack on how to improve its performance.

A spokesman for the Office of the Rail Regulator said yesterday: "The rate at which rails are broken has been reduced but Tom Winsor is not satisfied that it is being reduced by a big enough amount."

A firm of consultants from New Mexico, specialists in the management of rail technology issues, had been brought in and were due to report in November.

For Mr Smith, of the Rail Passengers Council, Mr Winsor's appointment has provided the necessary impetus to safety improvements. "He has made an enormous difference, both in terms of his personality and in driving the network forward," he says.

"The structure is being put right but it doesn't produce results overnight and in five years time passengers will experience a different, safer railway."

But for one of the main rail unions the real problem is not so much a lack of investment as the fact that the responsibility for railway safety rests with private companies.

"We have consistently felt that safety has been compromised because of the conflict of interest with profits," says Nick Cole, spokesman for the Rail, Maritime and Transport union (RMT).

"Privatisation has allowed one or two companies to squeeze costs and those things that are neglected will come back to haunt you. The problem now is a lack of maintenance and a lack of regular checks.

"Sooner or later that has got to have an effect on the number of accidents. The last few years has seen an unprecedented level of accidents and even in those put down to driver error you have got to look at what we're expecting from our drivers."

A spate of high-profile rail disasters since privatisation in May 1996 lends support to the RMT's position. Added to the Ladbroke Grove and Southall tragedies, two people were killed when two trains collided head-on at Watford Junction Station just months after shareholders took a stake in Railtrack.

But Health and Safety Executive figures issued just months before the Ladbroke Grove crash showed that from April 1998 to March 1999 no passengers were killed in train accidents for the first time in five years.

The number of significant train accidents, judged as potentially the most dangerous to passengers, was, at 104, the lowest level ever recorded.

Railtrack has also been forced to cope with a record number of passengers, increasing from 250 million a year in 1996 to one billion a year now. This winter will also see 1,500 more services a day than five years ago.

"Privatisation has resulted in a more fragmented industry and it could be said that some lines of responsibility have become blurred," says Alix Stredwick, campaign co-ordinator of the Railway Development Society. "But safety has always been at the top of the agenda.

"Railtrack has been criticised in the past for not maintaining the rail network to the standards it should be but we feel as a whole they are putting a lot of effort into improving performance."

But, says Anthony Smith, the belated recognition of the need to spend more on safety may be a hangover from privatisation. "The question is not whether it is owned by the public or the private sector," he says. "It is a question of how effective it is in providing what the country wants.

"In some ways the private companies have got more to lose - the train companies can lose their franchises and Railtrack can be fined for its safety lapses.

He adds: "The privatisation process was so unique and Railtrack was making it up as it went along. The problem may be getting the right privatised structure and that is only now starting to emerge."

It may be that the combination of a get-tough regulator and a commitment to improve, spurred on by Tuesday's tragedy, will start to make a difference.

But the flowers by the side of the railway lines are testament to the fact that there is still some way to go.