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Appointment of a railway civil engineer as Technical Director saw Railtrack start to get at grip on the crisis – well, thumb and first finger.
As this column was being written early in December new cases of gauge corner cracking were still emerging. But after the initial headless chicken impression, Railtrack had steadied, thanks to the appointment of Richard Middleton, previously its Commercial Director, as Technical Director.
In fact, even that appointment was bodged. According to Informed Sources, when the appointment was mooted Middleton jibbed at reporting to Chief Operations Officer Jonson Cox, a man whose railway experience in weeks was about the same as Middleton's years as a railway civil engineer.
Of course, the correct management response would been ‘On your bike, then'. But that would have frightened the City and Government, so now Middleton reports to the Chief Executive and was given an expanded empire. One up to railway power.
And from the railway's point of view it was a good move. With some technical authority (as in ‘its your arse if it goes wrong, Richard') at the top, Railtrack regained some confidence and announced on December 1 that ‘extensive engineering research' would allow several hundred of the Temporary Speed Restrictions (TSR) imposed after the Hatfield derailment to be eased.
Illustrating that this really is an epidemic, 3,700 sites where gauge corner cracking or head checking was present have been checked. TSR's were imposed at around 850 locations. By December 1 280 of these had been lifted following 117miles of re-railing.
Railtrack said that the decision to raise speeds followed consultation with Her Majesty's Railway Inspectorate. Interestingly Deputy Chief Inspector Bob Smallwood said on the BBC <Ital>Today<ital> ‘Railtrack is the duty holder, it is their responsibility for speed restrictions it is nothing to do with us'. But Deputy Prime Minister John Prescott says the HMRI advises him. Weird, eh?
Whatever, Railtrack reckoned that there were 200 sites where ultrasonic testing had indicated that 20mile/h TSRs could be raised to 40mile/h ‘over the next few weeks'. There was also ‘sufficient evidence' for a second 20mile/h lift at 140 sites where the original 20mile/h TSR had already been raised to 40mile/h.
Sites inspected 3700 20mile/h TSRs imposed 850 TSRs removed 280 TSRs remaining at 1/12/00 570 TSRs to be raised to 60mile/h* 140 TSRs to be raised to 40mile/h 200 20mile/h TSRs remaining 230 |
*Previously raised from 20mile/h to 40mile/h
This easing of TSRs was based on revised instructions on responses to gauge corner cracking issued under Richard Middleton's authority. They are similar to the procedures described last month.
Horizontal surface cracks over 30mm long, where ultrasonic testing has shown that there is no vertical penetration of the rail head, can be cleared for 60mile/h pending re-railing. Note the qualification ‘horizontal'. Remember that fatigue cracks run along the rail, typically at an angle of 5degrees to the horizontal, and are a few millimetres deep.
But something can cause a shallow horizontal crack to turn downward into the head, starting a tache ovale type failure which in turn can initiate a broken rail. Where ultrasonic testing reveals a crack starting to turn down the 20mile/hr TSR can be raised to 40mile/h if the rail is clamped.
Finally, where ultrasonic testing shows multiple defects, or cracking in planed lengths of switch rail, the current 20mile/h TSR will continue to apply. Switchblades, of course, can't be clamped.
Which leaves us still in the dark as to why the sudden epidemic.
Anecdotal evidence continues to finger privatisation. The phenomenon certainly emerged in the mid 1980s when Mill Heat Treated wear resistant rail was introduced. But fatigue cracking was restricted to high cant deficiency curves on high speed routes. Only during the 1990s did it start to spread to slower speed curves and on straight track where it is called head checking.
At one curve, where rails laid in 1986 had been transposed in 1994 to even wear the difference was marked.
Transposition puts the old gauge face on the outside, preserving it for posterity. In this case, the pre 1994 high side (outside of curve) gauge face showe no gauge corner cracking but normal side wear. The current high side face had gauge corner cracking but no side wear.
Hmm, a puzzlement.