1 week ago
24
Troubles on London Underground’s Northern line that have disrupted journeys for millions of commuters since Sunday could persist into next week, with engineers still baffled by the cause of the signalling fault.
Transport for London (TfL) is understood to be considering cancelling the weekend night tube service to allow time for extensive investigations if specialist engineers cannot fix the problem on Thursday night.
The service is the busiest line on the network, and although trains continue to run, the unidentified fault in the signals at Stockwell has slowed journeys and delayed services to the extent that passengers are unable to board and some stations have had to close owing to overcrowding.
The Northern line has become comparatively frequent and reliable since the introduction of upgraded signalling just over a decade ago. But this week’s problems, with severe delays affecting all branches of the service, have been an unwelcome throwback to an earlier era when it was widely known as the “misery line”.
Engineers have worked overnight every night since Sunday checking cables and signal boxes without identifying the problem. A separate signal failure at Tooting that affected the line on Tuesday was repaired the same day.
TfL believes the Stockwell failure is an unprecedented fault. Further checks on the tunnel infrastructure can only be carried out when the line is closed. Trains normally run throughout the night on Fridays and Saturdays with the night tube, but repairing the line for commuters is likely to be the priority this weekend.
The signalling system is wired, ruling out another cyber-attack on TfL like the one a year ago. Deliberate sabotage has also been dismissed due to the location of the fault.
Trains are still able to communicate with the automated signalling throughout the line, bar the section immediately north of Stockwell station.
Controllers are instead talking directly to drivers to guide them slowly through the tunnels when it is safe to operate.
Passengers are advised by TfL to avoid the Northern line where possible, with alternative routes likely to prove quicker.
London bus services along the route are also being affected by increased road traffic, as well as swiftly filling up with passengers diverted from the tube.
Nick Dent, TfL’s director of customer operations, said: “We apologise to customers affected by delays on the Northern line since Sunday. We have identified a fault with the signalling equipment around the Stockwell area that means our service controllers need to manually talk trains through this part of the network.
“Our engineers are working hard to identify and fix the fault, including deploying advanced test equipment, and we will do all we can to restore a good service as soon as possible.
“We are advising customers to allow extra time for their journeys, and to check before they travel using TfL Journey Planner or the TfL Go app.”
Passengers in the capital may at least be spared disruption from industrial action on the tube for some time. London Underground has offered unions a three-year pay deal of inflation increases as measured by the retail prices index – typically above the usual measure of inflation based on the consumer prices index. Aslef has formally recommended the offer, and the Rail, Maritime and Transport workers’ union has yet to rebuff it.
