Rush hour commuters could face delays on services to and from London Paddington due to signalling problems.
Trains will be delayed by up to 20 minutes due to problems between Paddington and Ealing Broadway.
There is no current estimate when normal service will resume.
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The crash, which took place at about 7am today (Thursday), involved three vehicles. One man sadly died as a result of the collision and his next of kin have been informed.