There are delays and cancellations on First Great Western services between London Paddington and Reading after a person was hit by a train. Some lines are blocked and other trains could be cancelled while emergency crews are on site.
It could add 30 minutes to journeys and will affect travel times to and from the westcountry.
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The evening will stay cloudy with drizzle and fog in hilly areas.
There will be early evening sunshine with a few patches of rain later on.
The Avon fire service has moved its headquarters from Bristol to share Avon and Somerset Police's Portishead base.