Train services in and out of London Paddington are suffering “major disruption” as emergency services respond to a casualty on the tracks.
There are currently severe delays on the Elizabeth line between Hayes & Harlington and Reading with minor delays between Paddington and Heathrow, according to TfL.
Great Western Railway services between Paddington and Reading are also affected.
National Rail Enquiries is warning trains running between these stations may be cancelled, majorly delayed by up to 65 minutes or revised.
It says disruption is currently expected to last until 6pm.
