Commuters on the Metropolitan line are experiencing severe disruption while safety checks are carried out after a fault was found in the wheels of some trains.
Engingeers carrying out routine safety checks found the fault “on a number of Metropolitan line trains” and so TfL has introuduced a reduced timetable to allow it to check the rest of the fleet.
Most of the trains on the line have only been in service since 2010.
Londoners should expect trains running every 30 minutes between Chesham and Amersham and Baker Street. From Uxbridge to Aldgate and Watford to Baker Street, trains will run every 15 minutes.
Peter McNaught, Director of Operational Readiness at Transport for London, said: “We identified a fault with some of the wheels on a number of Metropolitan line trains during our regular and routine inspections of our fleet.
“Safety is our top priority, and as a precautionary measure, we have increased the rate of inspection of these trains to make detailed checks of the entire fleet.
“We have introduced a special timetable on the Metropolitan line to ensure we continue to run as frequent and regular a timetable as possible while inspections take place and our engineers resolve the fault.
“We’re sorry that this may lead to some services and stations being busier than normal and advise customers to check before they travel.”
TfL has warned other lines may be busier than usual due to the disrupted service but insisted the fault only affects trains used on the Metropolitan line.
TfL said tickets are being accepted on London Buses and Chiltern Railways. It is unclear how long the temporary timeline will be in place for.