Summary
A railway tunnel portal in the Tudor-Gothic style, built c.1836-40 into the hillside under Birchwood Road.
Reasons for Designation
St Anne's Tunnel East Portal, built c.1836-1840 for the Great Western Railway, to the designs of Isambard Kingdom Brunel, is designated at Grade II* for the following principal reasons:
* Architectural interest: its Tudor-Gothic design illustrates Brunel's vision of engineering a line according to picturesque principles;
* Date: it is a remarkably intact structure from the pioneering first phase of railway development in England;
* Historic interest: it is constructed to a design by Isambard Kingdom Brunel who is widely regarded as one of the most important engineers and architects of the C19;
* Group value: it forms part of a sequence of Tudor-Gothic structures between Bristol and Bath, designed by Brunel in response to the scenic route along the Avon valley.
History
Great Western Railway
The Great Western Railway was authorised by an Act of Parliament in 1835 to construct a line from London to Bristol. At 118 miles this was slightly longer than the other major trunk railway of its time, the London and Birmingham (112 miles) and considerably longer than other pioneering lines. Construction of the line began in 1836, using a variety of contractors and some direct labour. The first section to be completed, from London to Maidenhead Riverside (Taplow), opened in 1838, and thereafter openings followed in eight phases culminating in the completion of the whole route in 1841. Work at the Bristol end of the line had started in 1835, and the section from Bristol to Bath had opened in August 1840.
The engineering of the railway was entrusted in 1833 to Isambard Kingdom Brunel (1806-59), who was already known for his engineering projects in Bristol. More than any other railway engineer of his time he took sole responsibility for every aspect of the engineering design, from surveying the line to the detailing of buildings and structures. He sought to achieve as level a route as possible and, working from first principles, he persuaded the Directors of the GWR to adopt a broad gauge of 7ft 0¼ in rather then the standard (4ft 8½in) gauge in use on other lines. A two track broad gauge line was 30ft wide, and this determined the span of the overbridges and other structures. Except for larger bridges such as Maidenhead Bridge, the majority of Brunel’s masonry bridges did not need to be as innovative as his works in timber and iron, and his structures followed the typical architectural idioms of his time, but they were all beautifully detailed and built and together they formed integral parts of a consistently-designed pioneering railway.
Although he left no written statement concerning his design concept for the line, it can be inferred from its design and from the way it was described when opened that part of his vision was a line engineered according to picturesque principles. This influenced his selection of the route and the design of structures along it. For reasons of cost, but also because it helped blend the railway to the landscape, he used local materials for bridges and other structures, ranging from stock brick at the London end of the line, to red brick, Bath stone east of Bath and Pennant stone west of Bath. This intentional variety was remarked on by contemporaries, for instance in J.C. Bourne, 'The History and Description of the Great Western Railway' (1846). On the line from Bristol to Bath (the 'B' section), where the track runs along the Avon valley, Brunel chose to use Tudor four-centred arches for both the over- and underbridges, and castellation for tunnel portals and viaducts. This makes it the most distinctive part of the whole route from London to Bristol, and it is also the section on which the structures have generally survived in their original form because this part of the route was not quadrupled and the Pennant stone used for most structures has lasted well.
St Anne's Tunnel
St Anne’s Tunnel was one twelve constructed by Brunel between Chippenham and Bristol. It was built c. 1836-40 and is 141m long. Original contract drawings for the East Portal survive. Other contract drawings for bridges and other structures on the Bristol-Bath section of the line carry the signature of I.K. Brunel, reflecting his involvement with every aspect of the project. The Resident Engineer was G.E. Frere (1807-87), assisted by G.T. Clark (1809-98) and Michael Lane (1802-68), but their individual contributions have not been identified.
On 6 December 1940 a bomb damaged the southern edge of the portal, demolishing part of the parapet and damaging the face (Maggs, 2001). Apart from repairs to this area and to the arch, the portal is unaltered.
Details
MATERIALS: Pennant stone throughout. Squared and coursed to portal face, soffit and attached retaining wall. Ashlar dressings: voussoirs, copings, crenulations, machicolations, quoins and side tower faces. Some engineering brick patching.
DESCRIPTION: asymmetric composition. Round arch with a span of 30ft (9m) composed of plain double voussoirs, a set back and chamfer. Some repairs in engineering brick, chamfered to replicate original. Plain spandrels beneath plain flat coping. Square tower on the north (Up side) with two arrow-loops, crowned by double-step corbelled machicolations supporting projecting embattled parapet with sloping copings. On south (Down) side the face abuts a battered, rubble faced retaining wall.
There are detached sections of retaining wall and buttresses against the face of the cutting towards Bath.
The Portal is at the western end of a short stretch of line running on a shelf between a steep hillside and the River Avon, which was diverted by Brunel. At the other end of this stretch is the West Portal of Fox's Wood Tunnel (MLN1 11622), which is listed Grade II*.
