Summary
A skew triple-arch road overbridge, with semi-elliptical arches and humpbacked profile, erected c. 1839-41.
Reasons for Designation
Hunts Mill Road Bridge, constructed c.1839-41, is designated at Grade II for the following principal reasons:
* Date: an early example of a railway structure dating from the pioneering phase in national railway development;
* Design: a characteristic Brunel design comprising an elegant skew, three semi-elliptical arches and stepped stringcourse;
* Group value: it forms a group with other architecturally-similar overbridges on the section of line between Wootton Bassett and Chippenham;
* Historic association: it is constructed to a design by Isambard Kingdom Brunel who is widely perceived as one of the most important transport engineers and architects of the C19.
History
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.
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).
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 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.
Hunts Mill Road Bridge was constructed c. 1839-41 on the GWR section between Wootton Bassett and Chippenham. This stretch of the line was never quadrupled and so the bridge has not been extended. However, in the later C19 or the C20 one side of the bridge was refaced in engineering brick, possibly in more than one phase.
Details
MATERIALS: appears to have been faced originally in squared and coursed Swindon 'Portland' stone, as on the roadway faces of the parapets. It was not possible to view closely the outside faces to understand the detail of the materials here, but some of the original facing material may have been replaced by a different stone, possible Bath limestone. The soffits seem to have been red brick from the outset, but have been patched in places with red or red and purple GWR engineering brick.
DESCRIPTION: skew of 41 degrees. Central arch with standard 30ft [9m] span, side arches narrower and not as tall. All three with voussoirs. Piers pierced by one transverse arch each, as per the norm for these Brunel bridges. Faces continue as gently curving wing walls, with stepped string course running all the way across. Parapets stepped on the internal face and topped by square edged copings with a very shallow-pitch. Tie rods with rectangular plates inserted beneath the string course.
