London Road Bridge (MNL13346)

Summary

A large triple arch skew road overbridge erected c.1838-40, set in a deep cutting.

Reasons for Designation

London Road Bridge is designated at Grade II for the following principal reasons:
* Date and historic interest: an early (pre-1840) railway overbridge dating from the first phase of the GWML and the ‘pioneering’ era of railway development in England;
* Design, engineering and material interest: an exceptionally large overbridge of elegant triple-arched design, built of high-quality local red brick;
* Intactness: apart from the rebuilding of the parapets, the main fabric of the bridge survives remarkably well;
* Setting: the bridge stands astride the deep Sonning Cutting, one of the major engineering features of the GWML.

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.

By the 1870s the growth of traffic, especially at the London end of the route, necessitated the widening of the line from two to four tracks. This was carried out in two stages, from London to Taplow in 1875-84 and from Taplow to Didcot in 1890-93. By the time of these widenings the broad gauge was being phased out (the final conversion to standard gauge took place in 1892), and the design of the extended or new structures took this into account. However the designs were exceptionally sympathetic to Brunel’s original designs, in form and detail; also in the choice of materials, although engineering brick, seldom or never used by Brunel, began to make an appearance in 1890s. The engineers chiefly responsible for the widened lines, whose names appear on the surviving archive drawings, were William George Owen (1810-85, Lancaster Owen (1843-1911) and Edmund Olander (1834-1900).

London Road Bridge was constructed under Contract 8L on a part of the route which opened in March 1840. The resident engineer for this section of the line was John Hammond. The original contract drawings for the bridge survive, but are not signed. It was built to carry the Great Western turnpike road from London to Reading (now the A4) over the Sonning Cutting. For this purpose its design and dimensions are grander than other overbridges. The cutting was one of the major civil engineering undertakings of the line, and was hand dug between 1838 and 1840. Because of these factors, the cutting and bridge were illustrated in Bourne, 'The History and Description of the Great Western Railway' (1846). On Christmas Eve 1841 the cutting was the scene of Britain's first major railway disaster, when prolonged heavy rain caused one of the earth banks to collapse; an early-morning westbound train collided with the slipped soil, and its three third-class carriages were crushed by the impact of the heavy goods wagons behind. Nine passengers died, and seventeen were seriously injured.

When the line was quadrupled in 1891 the bridge was not altered. Instead, the embankments were cut back and retaining walls erected to allow a line to be passed through each of the side arches. In this form, the bridge forms the backdrop to a celebrated photograph of the last GWR broad gauge service, taken on 20 May 1892. Between 1913 and 1932, the tracks were realigned to their present positions; three passing through the central arch, and the Up relief line passing through the northern side arch.

In one or more phases in the late-C19 or early-C20, the transverse arches through the piers were rebuilt as blind arches, brickwork was patched, the string course on the low mileage (east) side was removed, and the parapets were rebuilt. Strengthening works were undertaken at the northern end, including tie plates to both faces, in 1971.

In c. 1977-88 a concrete relief road bridge was erected close on the west side, at a slight skew.

Details

MATERIALS: original handmade red brick, laid in English bond, with some patching in red engineering brick, particularly around the arch rings. Bourne describes stone dressings including ‘cornice’ and ‘caps’ but only the coping appears now to be stone.

DESCRIPTION: three semi-elliptical spans: the central arch approximately 48ft [14.6m], the side arches approximately 44ft [13.4m]. The central arch is also marginally higher. Tall piers, tapered, each with a single transverse arch rebuilt as a blind arch. Impost bands appear to be rendered. Brick roll moulded string course to high mileage (east) elevation; that to low mileage (west) elevation now missing (small fragment survives at northern end). Raked and gently curved abutments/wing walls; that to the north-west curving to meet the line of the original turnpike road (Old Bath Road). Both parapets recently rebuilt in red engineering brick, although the low mileage side retains some original brickwork, including a chamfered plinth. Parapet coping to low mileage elevation is of modern reconstituted stone; that to high mileage elevation incorporates re-used original shallow-pitched coping stones.

The bridge is generally not visible in the wider landscape because it is in a cutting. However, it is visible from Warren Road Bridge (MLN13329).

Sources

Books and journals
Brindle, S, Cruickshank, D, Brunel: The Man Who Built the World, (2005)
Bourne, J C, The History and Description of the Great Western Railway, (1846)
Cross-Rudkin, P, Chrimes, M, EDS, Biographical Dictionary of Civil Engineers Volume 2: 1830–1890, (2008)
MacDermot, E T, A History of the Great Western Railway, (1927, revised ed. 1964)
Pugsley, A, The Works of Isambard Kingdom Brunel, (1976)
Vaughan, A, A Pictorial Record of Great Western Architecture, (1977)

Other
Alan Baxter & Associates, The History and Significance of the Great Western Main Line , 2012,
Kinchin-Smith, R, Crossrail Technical Assessment of Historic Railway Bridges , 2005,
Network Rail , National Records Centre, various historic drawings,

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