Summary
Tunnel portal in a classical style with a horseshoe arch, constructed at the end of a shallow cutting c.1873-86.
Reasons for Designation
The East Portal to the Severn Tunnel is designated at Grade II* for the following principal reasons:
* Engineering innovation: it is the entrance to the Severn Tunnel which was once the longest mainline railway tunnel in Britain and remains one of the outstanding feats of British railway engineering;
* Historic interest: the creation of the tunnel, opened in 1886, was one of the major developments in the history of the GWR line and signified a major leap forward in the efficiency of railway transport;
* Architectural interest: an elegant classical architectural composition in dressed stone with monumental pilasters.
* Intactness: despite some weathering to the stone work, the design of the portal remains largely unaltered since its construction;
* Association: it was one of the most notable structures to be designed by Charles Richardson, an early assistant to I.K. Brunel and one of the principal GWR engineers, along with consulting engineer Sir John Hawkshaw, both of whom are both widely regarded as two of the major figures in Victorian railway engineering;
* Group value: it has a strong group value with other listed structures on the GWR especially the remarkable sequence of highly graded tunnel portals.
History
The Severn Tunnel was constructed in 1873-86 and until 2007 was the longest main line railway tunnel in Britain. The incentive to dig the tunnel stemmed from the distance and inconvenience of the alternative routes to Wales, via Gloucester and a bridge across the Severn or by ferry from New Passage Pier north of Bristol. Charles Richardson (1814-96), the engineer for the jetties at New Passage Pier, conceived of the idea of a tunnel in 1863 but it was not until 1872 that the Great Western Railway obtained the necessary parliamentary powers to construct it. The route was from Pilning on the east shore to Rogiet (later Severn Tunnel Junction) in Monmouthshire. The tunnel was nearly 4½ miles long, 2¼ under water.
This was to be the longest railway tunnel under water yet constructed, presenting a number of unprecedented engineering problems - its length, the depth under the river, and the gradients necessary to reach that depth. The greatest problem was a large spring, later known as the Great Spring, which broke into the tunnel works in October 1879. Steam pumps had to be installed but it was until late 1880 that the water was pumped clear. As a result of that crisis Sir John Hawkshaw (1811-91), who had been consultant on the project, took charge of the works: he introduced T.A. Walker, a contractor well-experienced in tunnelling projects from his work on London's Underground Railways. The Great Spring again broke into the works in 1883, and in the same year a tidal wave on the river flooded the surface works. Permanent pumps were installed at Sudbrook on the Welsh side, which are still in use today and listed Grade II.
When completed in 1886 the Severn Tunnel was widely recognised as being a major engineering achievement, in length and magnitude of construction far exceeding any previous railway tunnels. Its construction was described in detail in Thomas A. Walker, 'The Severn Tunnel: Its Construction and Difficulties' (1886).
Details
MATERIALS: limestone ashlar, possibly of two different types giving a different colour above and below the cornice line.
DESCRIPTION: continuous radius horseshoe arch emphasised by a gigantic roll moulding. This is set in a straight elevation articulated by four bold projecting piers which rise up above the parapet: a slightly battered pair flanking the tunnel mouth, and another pair to terminate the wing walls. Running across this whole elevation is a simple stepped string course or cornice and an equally simple and bold coping. The piers are further emphasized by a second stage to their coping. In the centre of the parapet is a heavily worn plaque panel.
The designation is restricted to the outwardly-visible tunnel mouth and the short stone return inside the mouth; and while the Severn Tunnel itself is of significance as one of the outstanding feats of railway engineering, it is not included in the designation. The west portal is in Wales, and is not designated.
This list entry was subject to a Minor Amendment on 25/07/2012
