Engineering work is affecting First Great Western services between London Paddington and Bristol Temple Meads and Wales. An hourly service is running.
Trains are diverted via Oxford won't call at Reading or Didcot. There are buses between Swindon and Reading.
The London Paddington to Cheltenham service is also affected. Trains are only running to and from Didcot. Passengers for London should change at Oxford.
More top news
Rugby World Cup winner Phil Vickery talks about his World Cupexperiences and what he hopes this year's tournament will do for the game.
Rugby fans are eagerly awaiting the start of the Rugby World Cup but it's not just sports enthusiasts who will benefit this autumn.
The last pilots to train on Lynx and Sea King helicopters in Somerset have taken part in a parade in front of some special guests.