Engineering work is taking place between London Paddington and Ealing Broadway, closing 2 out of 4 lines.
It is not yet known how Elizabeth line will be affected by this engineering work.
Long distance:
Trains will run to an amended timetable, and will be retimed to run between London Paddington and Reading several minutes earlier or later than usual.
Some trains will additionally call at Twyford, Maidenhead and Slough.
Local services:
For most of the day, trains which usually run between London Paddington and Didcot Parkway will be amended to run between Reading and Didcot Parkway only.
You can use alternative Great Western Railway services between London Paddington and Reading at no extra cost.
After 09:55, trains will run between London Paddington and Heathrow Terminal 5 every 30 minutes, instead of every 15 minutes.
If you are travelling with Great Western Railway or Heathrow Express, you can plan your journey using the National Rail Journey Planner.
If you are travelling with Elizabeth line, these changes are not currently shown in the National Rail Journey Planner, please check back nearer to the time of travel.