A TRACK fault with chilling similarities to the Potters Bar crash was discovered on a North-East stretch of the East Coast Mainline, The Northern Echo can reveal.

The company responsible for the upkeep of the high-speed rail link, Jarvis, said nuts had been removed from a set of points near Darlington railway station.

Jarvis said the removal was "very suspicious" and it is not ruling out sabotage.

The incident, four years ago but never fully made public until now, increases fears over safety following the Potters Bar crash which killed seven people, say passenger groups.

There, two sets of nuts were missing and a further nut was too tight, pulling the track out of position.

Jarvis has since claimed that a sophisticated saboteur with informed engineering knowledge tampered with the points, but the firm has been accused of trying to shift the blame away from its staff.

Last night, it said that workers carrying out a routine maintenance check at Darlington South junction, a couple of hundred yards south of the station, logged the missing nuts on July 30, 1998.

They were replaced, having been secured just two days previously, with the repair work leading to a delay on the line.

John Smiles, of Jarvis, said: "There was potential for a points failure, although not as catastrophic as that at Potters Bar.

"How serious it would have been would have depended on the physics of any train going over it and a number of other circumstances.

"We never thought a member of staff was to blame and, unless it was a very, very unusual occurrence where the nuts vibrated loose, the only other explanation was that a third party had come along and tampered with them."

The incident of missing nuts, on a stretcher bar which held the rails equal distance apart, was reported to Railtrack and the British Transport Police, said Mr Smiles.

But no further action was ever taken against any individual, to the best of the company's knowledge.

Ernie Preston, secretary of the North-East Rail Passengers Committee, said: "We are very concerned about any fault such as this on a passenger line.

"As a passenger group we would obviously hope responsible contractors would report this kind of thing and action be taken to prevent a re-occurrence."

The junction where the fault occurred was described by Railtrack as a "high trespass and vandalism" area.

Only last week, The Northern Echo revealed how a problem with trackside junk in the same location was due to lead to a court action by the Health and Safety Executive against Railtrack.

Railtrack said it had recorded a points incident on July 30 1998, but could add no further detail.

It is keeping an "open mind" over the cause of the Potters Bar rail crash until the full investigation is completed.

A transport police spokes-man said: "Jarvis has come up with half-a-dozen incidents of points being tampered with and it does happen.

"It would though take quite a bit of effort and you'd need some pretty hefty equipment."