NETWORK RAIL is to switch on the overhead electrification within the Severn Tunnel in April for testing. If successful, it is hoped regular passenger services will be able to operate under electric power through the tunnel from May.

Overhead conductor bar was installed in the tunnel during 2016 but has proved troublesome. Electric services west of Bristol Parkway to Cardiff began operating in January, but GWR’s bi-mode Class 800/802s have been operating through the tunnel on diesel pending resolution of the difficulties.

A spokesperson for Network Rail said: ‘We’re undertaking modifications to the contact system assets within the Severn Tunnel to improve the system resilience. We plan to energise the tunnel in mid-April and commence a period of live electrical testing, during which the system will be monitored and its performance assessed. On completion of the testing, we will be in a better position to understand what further action is required, if any.’