THE DOWNGRADING of remedial action to track defects as part of a trial of a newultra-sonic track-testing regime poses a serious safety risk to rail staff and passengers, the industry's biggest union says today.

RMT has asked the railways inspectorate to investigate the 12-month trial, already under way in northeast England, in which Network Rail has selectively downgraded the response to some defect types discovered by the high-speed ultra-sonic testing train.

The trial's lower standards will see some rail defects that would otherwise be clamped and replaced on a strictly prescribed timescale left unprotected and replaced over longer periods.

The inspectorate is already investigating evidence gathered by the union that the ultra-sonic train misses some track defects altogether and should not be relied upon to the exclusion of other inspection methods.

"This trial amounts to a lowering of safety standards that will see defective rails simply left to deteriorate even further, and RMT believes that poses unacceptable risks for our members and rail passengers," general secretary Bob Crow said today.

"There is also no explanation in any of the briefing materials that explains the reasoning behind the trial, so we can only assume that it is being done to save money.

"It was failure to replace defective rails that caused the Hatfield crash and the deaths of four people, and our fear is that Network Rail has failed to learn those lessons.

"Network Rail has failed to consult RMT over the trial, and it has even by-passed the Ultra-Sonic Working Party that was set up to discuss safety-critical issues.

"We already have a thick dossier of defects, some of them very serious, which were missed by the ultrasonic testing train but picked up by other inspection methods.

"Ultra-sonic staff are also being pressurised to comply with these lower standards, and we give Network Rail fair warning that any attempt to discipline our members for upholding safety standards will be met with a ballot for strike action," Bob Crow said.