Signalling issues between Slough and Maidenhead are causing train delays between the stations this afternoon.
Operator Great Western Railway has tweeted to say Network Rail is investigating the issue, but trains may be cancelled or delayed by up to 30 minutes.
Network Rail has tweeted to say it expect disruption to continue until 6pm.
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.