RAILTRACK HAS launched a £2M emergency spending programme to combat a sudden rise in broken rails on the West Coast Main Line.
An unexpected increase in icidents last September, particularly between Euston and Rugby, has seen the number of broken rails since April last year rise by 39% over the previous year.
Railtrack admitted it was still unsure of the cause of the sudden spate of failures. In addition to the urgent rerailing programme it is to work with Aston University to investigate the breaks.
So far five possible causes of breaks have been identified:
metallurgical faults in batches of rails
rails reaching the end of their working life
an increase in rail traffic
an increase in wheel impact on the track from 'wheel flats' - flat-spots on wheels from skidding
a change in rail grinding by the track maintenance contractors.
Midlands zone infrastructure contracts manager Chris Dickinson said: 'From September we have seen an unseasonal rise in the number of broken rails. Most of the problem has been on older track on the WCML.
'The problem mainly affects the fast lanes,' he added. 'We have launched a £2M urgent rerailment programme - given how stretched we are this is a lot.'
Maintenance contractor GTRM is also carrying out extra surveillance work to identify problem areas. This has meant doubling the number of runs by high-speed track-recording vehicles and the introduction of an ultrasonic scanning trolley that can detect defects in the rails.
GTRM operations director Jol Bates explained that plots of rail defects against age revealed that the breaks were happening on parts of the fast lane track that was laid about 20 years ago.
'It came as a bit of a surprise. But now that we are a few months into the programme we can see what is happening. It is a cyclical problem to track put down in the early 80's which in turn replaced track renewed in the 60's.'
However, Railtrack's tests have also shown that the increase in 'wheel flats' is significant. These can cause up to four times the impact of normal wheels.
Dickinson said: 'We don't fully know why there are more wheel flats. We may have to revise what is acceptable. It comes down to the maintenance regime. We have talked to our maintainers [the train operating companies] and have highlighted what we think is the problem.'
However, he denied that the rise in broken rails related to Railtrack's decision last year to shift emphasis in its infrastructure spending away from track renewals to maintenance, to get better value for money.
'Euston to Rugby is the busiest mainline in the world. The track normally degrades and we have seen a 9-15% growth in traffic on the WCML.' Railtrack is now developing a predictive model that can link the occurrence of broken rails to the amount of traffic on the rails.
The Midlands zone plans to renew about 20 miles of rails on the WCML every year for the next five years as part of the modernisation of the WCML. This year it will spend £20M on renewals.