RAIL CONTRACTORS have been working to out of date drawings and specifications for points and switches across the British rail network, the Railway Inspectorate told NCE this week.
The discovery emerged during checks ordered after the Potters Bar crash in May (NCE 16 May). Seven people died when a set of points on a stretch of track maintained by Jarvis failed, derailing the last carriage of a train travelling at almost 150km/h.
Missing nuts loosened 'stretcher bar' assemblies causing one to fail, allowing the point blades to move independently, narrowing the gauge at the points.
Speaking after the launch of a Health & Safety Executive (HSE) report into the crash, Deputy Chief Inspector of Railways Dr Bob Smallwood told NCE: 'We found that some infrastructure maintenance companies were working to out of date drawings, while some were working to different information in different parts of the network.
'Some had not obtained from Railtrack the information which they should have received to enable them carry out maintenance work, ' he added.
The report calls on Railtrack to ensure all contractors involved with points maintenance 'have copies of, and understand, the relevant standards, drawings, specifications, and other documentation required to enable points to be installed, set, adjusted, maintained, inspected and tested to the identified requirements'.
Investigators also found the failed Potters Bar points 2182A 'were set up differently to the drawings'. Head investigator Frank Hyland said that archive video footage taken of the points existed and that may help determine when modifications to them were made. This could have occurred any time since the points were installed in 1994, and before Jarvis took over maintenance of them in April last year.
The points were also discovered to have defective 'lost motion' fittings - devices which are supposed to allow small movements at different ends of the points. Incorrect fitting could lead to 'a higher rate of fatigue loading or vibration to components' which 'could contribute to nuts loosening'.
The report states that 'variability of maintenance and inspection of points across the network must be addressed'.
Smallwood said that none of the 240 points inspected by the HSE's Railway Inspectorate were found in the same condition as those which failed at Potters Bar.
However, the state of three sets of points maintained by Carillion Rail (formerly GTRM) on the West Coast Main Line near Wembley was such that a formal Improvement Notice was served on the contractor and Railtrack, due for compliance by 15 July.
The report also reveals that 20% of the nuts on points in the Potters Bar area checked shortly after the crash were found to be loose. These included sets close to Hatfield station, near the scene of the fatal crash in October 2000 on track then maintained by contractor Balfour Beatty.
INFOPLUS www. nceplus/magazine/rail