Accomodation footbridge over the main line of the Stockton & Darlington Railway, 1857 by John Harris of the Hopetown Foundry, Darlington, with the two spans added 1868-1869.
Reasons for Designation
Thickley Wood Bridge is listed Grade II for the following principal reasons:
* for the very long single-piece castings forming the main span of the 1857 bridge, cast iron rarely being used for long spans after the 1847 River Dee Bridge disaster;
* the three C19 spans together demonstrating differing approaches to mid-C19 bridge construction, both the cast iron and wrought iron beam bridges being nationally rare survivals.
* built initially for the pioneering and internationally influential Stockton & Darlington Railway, being an example of the company’s approach to contracting work to local businesses.
* one of a group of early railway structures in Shildon, dubbed the ‘cradle of the railways’.
Thickley Wood Bridge is thought to have been built as a replacement of a level crossing 50m to the west, probably as an accommodation bridge for cattle belonging to East Thickley Grange, improving access to fields to the south of the Stockton & Darlington Railway (S&DR). The first edition Ordnance Survey map, surveyed 1856, shows the level crossing and the railway having four lines at this point. The bridge was built in 1857 by John Harris (1812-1869), the substantial, single-span castings for the bridge being made at his Hopetown Foundry in Darlington. Harris had taken over from Thomas Storey as the S&DR’s resident engineer in 1836 and was employed as a contractor for the permanent way (the track and track bed) from 1844. He is reputed to be one of the earliest railway engineers to have promoted the use of timber sleepers in preference to stone sleeper blocks.
Additional sidings to the main line required the addition of further bridge spans to the south, the first being a small masonry arch forming an abutment for a wider wrought iron girder span added in 1868-1869. The masonry arch may have been built to allow access through the approach embankment for pedestrians or carts (it is now - 2021 - too low for standard gauge rail access) however changes in the stonework clearly show that the level of both of the flanking beam bridges have been raised and that their height clearance was originally similar to that of the masonry arch. Around 1875, a further four spans were added on the south side of the bridge, these being of iron lattice girder construction. The Ordnance Survey map, surveyed in 1896, shows 17 lines passing beneath the bridge, two being the running lines of the main line, the rest being part of the very large marshalling yard, Shildon Sidings. This yard expanded to include 27 miles of sidings at its peak, being the world’s largest marshalling yard until it was superseded in 1927 by one in Chicago. Much of the traffic utilising the yard consisted of coal wagons: Shildon forming the collection point for the numerous collieries in the surrounding area to form coal trains departing on the 18-mile journey to Newport. The Shildon to Newport route was electrified from 1916 using a 1500V DC overhead system but falling traffic and the need to replace equipment saw a return to steam haulage in 1935. By 2018 just two running lines and a siding passed beneath the bridge, the lattice girder spans being redundant and failing. These lattice spans were subsequently replaced with an approach embankment and a single span of welded steel construction all designed under the direction of Network Rail to be in sympathy with the original form of the bridge. The earlier three spans were carefully repaired at the same time, the bridge being reopened as a footbridge in 2019.
The pioneering S&DR, which began commercial operation in 1825, was highly influential in the establishment of other railways both in England and abroad. It proved to be highly profitable, finally being absorbed into the North Eastern Railway on very favourable terms in 1863. One of the particular features of the S&DR was the way in which it tended to operate by contracting work to local businesses and engineers, rather than undertaking work in-house, the original span of Thickley Wood Bridge, and the involvement of John Harris, being a good example of this approach.
Railway footbridge, 1857 by John Harris for the Stockton and Darlington Railway, extended 1868-1869.
MATERIALS: cast iron, wrought iron, hammer-dressed sandstone with rock-facing to the quoin stones, and brick.
DETAILS: the bridge is of four spans and now has a long approach-embankment to the south (the embankment* together with the southernmost welded steel span* were built in 2018 to replace lattice girder spans dated 1875). The northern three spans are C19:
The earliest span (1857) is the northernmost. This is of 16.5m constructed as a cast iron beam bridge, utilising single castings for the sides of the bridge, these being linked by transverse brick jack arching that supports the bridge deck. The castings carry prominent makers plates reading ‘HARRIS * MDCCCLVII * MAKER’. This span retains its original cast iron balustraded parapet which has been heighted with an additional handrail. The northern bridge abutment is of masonry with curving wing-walls, the parapet terminating with brick-built piers with stone pyramidal caps. The raising from its original height is marked by a change in the stonework to the abutment. Fixed to this stonework are two metal brackets carrying ceramic insulators, these being part of the electrification of the line, installed 1914-1916.
The southern end of the 1857 bridge is supported by a short masonry span. This is mainly stone-built, but with the single semi-circular arch formed with four arch-rings of brick headers, brick also used for the raised parapets. The original base of the parapet is marked by a dressed stone band. The raising of the level of the iron spans to either side is marked by the addition of courses of stonework that are more smoothly dressed than that of the rest of the bridge.
The third span from the north is 10.9m and dates to 1868-1869. It is an iron beam bridge constructed of two wrought iron I-beam girders linked by wrought iron ties finished with a timber deck, its southern end supported on a masonry pier. The welded steel parapets* to this span were added in 2018.
* Pursuant to section 1(5A) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (‘the Act’) it is declared that these aforementioned features are not of special architectural or historic interest, however any works which have the potential to affect the character of the listed building as a building of special architectural or historic interest may still require LBC and this is a matter for the LPA to determine.