There are more delays and cancellations to trains between Reading and London Paddington today due to over-running engineering works.
The works have left all lines blocked, suspending services in both directions until at least 11am.
Services are expected to be disrupted until noon, and some services may still operate between Slough and Reading but there is no replacement road transport.
First Great Western is advising customers not to travel unless their journey is essential, and tickets dated for today will be accepted this afternoon and tomorrow.
They were hit by further setbacks as the 9.23am South West Trains service to London Waterloo has been delayed by nearly an hour until 10.19am.
The 9.53am service is expected to run on time.
Top Ten Articles
The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.