Great Western Railway (GWR) is advising customers to plan their journeys in advance this Christmas and to travel as early as possible, with Network Rail continuing its work to modernise the Great Western mainline.

On December 24 and December 27 trains will not be able to operate to or from London Paddington.

While some services will be diverted to London Marylebone these will be limited and in high demand; and the majority of services will terminate at Reading or Slough.

GWR Operations Manager Rob Mullen said: ‘We advise customers to plan their journey in advance at GWR.com and travel on or before December 23 if possible.

‘While we recognise the disruption this work will cause, and thank passengers in advance for their understanding, it is vital to enable us to run more electric trains delivering more seats and more frequent services.’

Local trains in the Thames Valley will operate between Reading and Slough, where replacement bus services will take customers onwards; however, these journeys will be significantly longer and buses are expected to be busy.

Chris Fuoco, senior incident officer at Network Rail, said: ‘We are urging passengers to check before you travel over this Christmas period as Network Rail undertakes a £40m investment on the Great Western Main Line and Crossrail as part of our Railway Upgrade Plan. 

‘This package of work is vital in order to accommodate GWR’s new fleet of trains and to enable Crossrail services to begin at the end of next year. 

Thursday December 21 and Friday December 22:

A normal service will operate.

Saturday December 23:

Some platforms at London Paddington will not be available for GWR to use which will affect the arrival and departure times of a small number of trains.

December 24 and 27:

The railway between London Paddington and Slough will be closed

Christmas Day and Boxing Day:

No service.

December 28 to 31:

A reduced weekend service will be in operation to and from London Paddington

January 1:

A normal Bank Holiday service will operate

The Network Rail upgrade work will also affect Heathrow Express and Heathrow Connect services with no trains between Heathrow and London Paddington from 24 to 27 December.

Passengers can visit GWR.com/Christmas2017 for further information.