The closure of Marylebone station in London remains in place following a cable fire. A statement from Chiltern Railways explaining the problem said:
"Around 2 metres of signalling cable in the tunnel into the station has burned away meaning the signalling system is not working.
"Without signals we cannot safely run trains, so are not running to or from Marylebone until new cables are installed and tested. We are not sure how long this will take, but we may not be able to run until Monday morning.
Work is underway on a £300 million project to create a new railway line linking Oxford and London Marylebone. The new Chiltern Railways route should ease overcrowding across the Thames Valley with more trains to the capital.
Interviewees: Patrick McLoughlin, Transport Secretary and Rob Brighouse, Managing Director of Chiltern Railways
The Transport Secretary Patrick McLoughlin has been in Oxfordshire today to start work on a multi-million pound project to create a new rail line between Oxford and London Marylebone.
The new Chiltern Railways route should ease overcrowding across the Thames Valley with more trains to the capital.
The journey to London will be less than an hour and the work will take a year to complete. The Transport Secretary said it was frustrating how long it had taken to get the project underway.
There are delays of up to 30 minutes on Chiltern Railway between Marylebone and Princes Risborough due to a broken down train at High Wycombe. It's mostly affecting northbound services. There is no estimate for when a normal service will resume.
Video: 86 per cent of Chiltern trains ran on time over the past 12 months. Southern Trains were below average with 55 per cent punctuality. Less than half of Virgin and Cross Country trains were on time.
There are delays of up to 40 minutes on trains running from Oxfordshire into London Marylebone.
Chiltern Railways says this is due to problems with line side equipment between Beaconsfield and High Wycombe.
Services from Aylesbury in Buckinghamshire are also affected.
Normal rail service resumed on Chiltern Railway between Banbury and Bicester North following earlier electrical supply problems at Kings Sutton