Northern line
On 13 August 2010, a defective rail maintenance train caused disruption on the Charing Cross branch, after it travelled four miles in 13 minutes without a driver. The train was being towed to the depot after becoming faulty. At Archway station, the defective train became detached and ran driverless until coming to a stop at an incline near Warren Street station.  This caused morning rush-hour services to be suspended on this branch. All passenger trains were diverted via the Bank branch, with several not stopping at stations until they were safely on the Bank branch.