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.
More top news
A Kent school has issued a newsletter naming and shaming the parents who drive over a nearby cemetery to pick up their children.
Friday night's forecast for the east of the region
Friday night's forecast for the west of the region