Summary
A triple-arch overbridge erected in c.1837-9, set in a cutting.
Reasons for Designation
Southbury 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 the ‘pioneering’ era of railway development in England;
* Design, engineering and material interest: a typically Brunellian overbridge of triple elliptical-arched design;
* Intactness: although the southern abutment has been rebuilt and the parapets renewed, the main fabric of the bridge, including the three principal arches, the piers and the northern abutment, survives intact.
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 1890-3. 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).
Southbury Lane Bridge was constructed on a part of the route which opened in July 1839. Brunel’s resident engineer for this section was John Hammond. The bridge was extended on the south (Down) side for line quadrupling in 1890-3. Drawings for the extension survive, dated 1890 and signed by Edmund Olander.
Details
MATERIALS: stock brick, laid mostly in English bond with some parts in Flemish bond; some spalling. Some red and purple engineering brick on the south (Down) abutment. Limestone coping.
DESCRIPTION: three 30ft [9m] semi-elliptical spans; single round-headed transverse arches to the piers. Impost blocks appear to be rendered. Stepped string course to both faces. A straight joint in the high mileage parapet wall suggests some rebuilding. Limestone shallow-pitched parapet copings. Granite spur-stones protect the parapet walls from wheel strikes. Raked and curved abutments/wing walls. In 1890-3 the cutting was widened and regraded on the south (Down) side and the southern abutments/wing walls were rebuilt in contrasting red and purple engineering brick to allow an additional two tracks to run through the southern side arch, which was retained.
Southbury Lane Bridge is located on the southern edge of the village of Ruscombe, very close to the Grade I listed Church of St. James which was rebuilt in the C17.
