There are delays of up to 30 minutes on First Great Western services between Taunton and Bristol Temple Meads due to cows having been on the line at Nailsea and Backwell.
Lines are now open but delays are expected until around 9am.
More top news
Police evacuated hundreds of homes in the city following the discovery of two suspect packages.
A large part of Exeter city centre has been evacuated following the discovery of two suspicious packages
More than 175,000 festival goers will be at Glastonbury Festival this weekend. We've made a list of people you're sure to encounter.