Summary
Railway bridge. Built c.1839-40 to the design of Isambard Kingdom Brunel.
Reasons for Designation
Bourton Bridge is designated at Grade II for the following principal reasons:
* Date: Bourton Bridge dates from c.1838-40 and therefore belongs to the first, ‘pioneering’ phase of the GWR, and of railway construction nationally;
* Design and engineering interest: while refaced, this is a particularly elegant example (curving in elevation and plan) which captures the essence of this design very well;
* Historic interest: it was designed by Brunel himself;
* Group Value: Bourton Bridge and Bourton Church Bridge form a pair of close and inter-visible Brunel-period bridges. This is a rare instance on the line of a pair of bridges in this particularly striking triple-arch design, the only other known example being at Dauntsey in Wiltshire.
History
The Great Western Railway (GWR) 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.
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 JC Bourne, 'The History and Description of the Great Western Railway' (1846).
Surviving contract drawings for bridges and other structures on this section of the line carry the signature of I.K. Brunel, reflecting his involvement with every aspect of the project. The Resident Engineer was GE Frere (1807-87), assisted by GT Clark (1809-98) and Michael Lane (1802-68), but their individual contributions have not been identified.
Bourton Bridge was built 1839-40 on the Challow to Wootton Bassett section of the line, which opened on 17 December 1840. The original contract drawings are signed by Brunel and the contractor James Bedborough and are dated June 1839. This stretch of the line was never quadrupled and so the bridge has not been extended. In the late C19 or early C20 the bridge was mostly refaced in engineering brick, possibly in more than one phase.
Details
MATERIALS: some original red brick in the arch rings and lower piers (and possibly soffits), otherwise elevations and parapets refaced in red engineering brick with purple engineering brick detailing. English bond.
DESCRIPTION: a triple-span overbridge with semi-elliptical arches and sweeping hump-back profile. Central arch with standard 30ft (9m) span; side arches are lower and have 20ft (6m) spans. Piers with a single transverse arch each. Plain purple engineering brick string course (originally moulded). Parapets terminate in piers projecting on the outer face only, at the ends of the raked and curved wing walls. The inner face of the parapets have low chamfered plinths. Coping is bull-nosed purple engineering brick except for the terminating piers, which have quarry-faced stone blocks.
The bridge is isolated in a rural landscape, but it is inter-visible with the near-identical Bourton Church Bridge (MLN17169), ½ mile up the line towards Didcot.
