The Severn Tunnel construction began in 1873 and the tunnel was opened in 1886, several shafts were driven down on the Welsh side of the river and one on the Gloucestershire side to construct the tunnel.
During these constructions problems were encountered on hitting water from an underground spring which required the installation of extra pumps.

Detailed information on the construction of the Severn Tunnel can be found on the Great Western Railway Archive web site on the links menu.