MARYLEBONE station will remain closed until further notice, Chiltern Railways have announced this afternoon.
Engineers are currently on site to replace signalling cables which were destroyed in a fire over the weekend.
But no trains to stations in Bucks will be able to depart the station for the rest of the day while work to fix the signal system is carried out.
Chiltern Railways, the company while operates the franchise through stations in the county on the line to Marylebone, is running a reduced service.
Passengers on the main line are being advised to change at Ruislip for a Central line train into London, while services from Aylesbury and Amersham are terminating at Harrow-on-the-Hill.
Tickets for Chiltern line trains are being accepted on Virgin Trains, London Midland, First Great Western, CrossCountry and London Underground services until further notice.