4 In July 2000, due to a combination of factors, a northbound Northern Line train was able to roll southbound (on the northbound track) for nearly 1km before stopping near Chalk Farm station. The train then remained stationary for approximately 10 minutes, meaning a short delay to passengers who got off and caught the next Edgware train. There were no passenger injuries or asset damage, but LUL launched an immediate investigation as there would be potentially serious consequences from any repetition.
5 As a result of the investigation, LUL decided to introduce a special project into the contracts that specified runback protection on all train fleets, except Central and Victoria (which already incorporate runback protection as part of their Automatic Train Protection). The introduction of these systems is expected to prevent reoccurrence of a train accidentally running backwards. LUL report there will be a very slight impact on reliability, of an anticipated additional 20 failures per year across the network (equivalent to one failure every three million kilometres). LUL will consider limited relief from asset performance requirements over the six month post-implementation period.
6 The work programme will run for most of 2004 and 2005 and is expected to cost LUL some £18.5 million across all affected lines of the network. LUL do not expect there to be any direct operational impact, with the changes involving the refitting of only one train at a time. The general risk of inadequate supply of sufficient operational trains remains with the Infraco, although an exception would be made if there were not enough operational trains because of the runback protection work programme.