Great Western Railway (GWR) has set up a dedicated webpage at www.gwr.com/christmas which sets out the affected areas and the changes this will mean to journeys.
This year there will be work at Southall, Westbury, Guildford and Severn Tunnel Junction and the range of work means that services on the North Downs, West of England, South Wales and Bristol lines are affected, some with diversions and others with replacement buses.
GWR recommends that customers make their Christmas getaway by Saturday 22 December as work will start from Sunday 23 December and on many routes will continue through to the New Year.
As in previous years there will be no trains on Christmas Day or Boxing Day.