A fault with the signalling system at Langley means that trains have to run at reduced speed.
As a result, trains running between London Paddington and Reading may be delayed by up to 25 minutes.
This is expected until 16:00.
Check before you travel:
You can check your journey using the National Rail Enquiries real-time Journey Planner
Twitter:
If you would like to follow this incident on Twitter, please use #Langley
Compensation:
You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.