Passengers using Chiltern services in and out of Marylebone on Tuesday faced overcrowding and cancellations due to a shortage of trains.
Marylebone is the only mainline station in central London still to use diesel trains. On Monday night Chiltern Railways warned that services to and from Oxford would be reduced from every 30 minutes to one an hour because of fuel supply issues at one of its depots, which meant that not enough trains were available to run on Tuesday.
Buses replaced trains between Aylesbury Vale Parkway and Amersham, meaning there was no service in or out of Marylebone on this line.
A Chiltern Railways spokesman said: “Rail replacement buses are in place between Aylesbury Vale Parkway and Amersham to convey passengers for connections to the London Underground. The rest of the network is operating as normal.
“We took this decision due to the public transport alternatives available. Ticket acceptance is in place with GWR until further notice between Oxford and Paddington, and our rail replacement bus service will connect into services for Central London.
“We’re very sorry to customers affected by this, and are working hard to repair the fault as soon as possible. Our hope is that this is done in the next few days, but we will continue to update customers.”
