From the Network Rail press release:
Severn Tunnel to be closed today for engineering inspection into feasibility of future electrification
Due to last minute changes in our planning for this essential preparatory work, the full inspection of the Severn Tunnel by our team of electrical engineers is to be brought forward to today.
In view of the existing alterations to passenger services over Easter, due to continuing work on the improvements to the station infrastructure at Reading, we believe it is appropriate to bring forward our planned work on the Severn Tunnel. This is intended to minimize any further inconvenience to the travelling public and freight operators by closing the tunnel for this essential survey work at any future date.
Our engineers will be surveying the full length of the Severn Tunnel to ascertain where it will be best to fit electrical power supplies ^ whether third rail or overhead lines ^ to assist us in preparing for the proposed electrification of the Great West Main Line.
This essential survey work should be completed by mid-day today at the latest, and should thus cause the minimum of inconvenience to all those using the railway at this particular time of year.
Network Rail spokesman Neil Downe said: ^The provision of road replacement services during this morning will be a matter for the train operating companies involved.^
A First Great Western spokesman would not be drawn into commenting officially, but expressed his personal opinion that travelling on any road replacement services between Pilning and Severn Tunnel Junction could take longer than waiting for rail services to resume, hopefully at mid-day today.
