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.
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James Wright has Monday's forecast for the east of the region.
James Wright has Monday's forecast for the west of the region.
For the second time this month, the region has been hit with heavy snow - leading to disruption and a number of events being cancelled.