BBC» article on the latest situation (link below.)
http://news.bbc.co.uk/1/hi/england/7206696.stmFGW▸ said it hoped to run a full morning peak service between South Wales and London on Friday.
But journeys will be up to 30 minutes longer due to temporary signalling.
Off peak, only an hourly service will run in both directions between London Paddington and Swansea, with extended journey times of 30 minutes.
First Great Western spokesman Richard Smith, said the line needed to be "completely rebuilt", including stabilisation work, new foundations, and new track and signalling.
"Until we can get engineers to the site to see the damage, we won't know what caused it, but it has covered several boxes that control points," he said.
Apparently, 40 miles of track between Bristol and Swindon were affected by the problem.
Further article link.
http://thisissomerset.co.uk/displayNode.jsp?nodeId=147472&command=displayContent&sourceNode=243687&home=yes&more_nodeId1=242222&contentPK=19665427