 A crenellated ventilation shaft of the tunnel | |
| Overview | |
|---|---|
| Line | South Wales Main Line |
| Location | Cotswold Hills, outside Badminton, Gloucestershire |
| OS grid reference | TQ 30404 84602 |
| Status |
|
| System | National Rail |
| Start |
|
| No. of stations | None |
| Operation | |
| Owner | Network Rail |
| Operator | |
| Traffic | Mixed |
| Technical | |
| Length | 2.5 mi (4.0 km)[1] |
| No. of tracks | 2 |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) |
| Electrified | 25 kV 50 Hz AC |
Chipping Sodbury Tunnel is a railway tunnel that is situated on the South Wales Main Line in England. It runs under the Cotswold Hills for 4444 yards, approximately 2+1⁄2 miles (4.0 km) west of Badminton railway station and Chipping Sodbury Yard.
The tunnel was built between 1897 and 1902; it was amongst the last of the major railway tunnels to be constructed in Britain. Built to hide the line from the nearby Badminton House, a total of six crenellated ventilation shafts are present. The tunnel was built with a mess room at the mid point so that maintenance crews could remain in the tunnel for the whole working day/ night. Due the tunnel passing through an underground aquifer, it has been particularly prone to flooding and associated closures. It was also a secondary target for Luftwaffe bombing during the Second World War.
Numerous remedial works and improvements have been made to the tunnel throughout its service life. Such works have largely been centred around improving its drainage and other measures to reduce the occurrence of flood-related closures. A new high-capacity drainage system was installed during the 2010s. In the same decade, the tunnel was temporarily closed as part of the modernisation of the Great Western main line, for which overhead electrification equipment was installed throughout its length, enabling electric traction to traverse the tunnel.