Blue Bridge, Wolverton

Blue Bridge was built in the 1830s to span the London and Birmingham Railway (L&BR) but now spans an empty cutting near Wolverton Works in Buckinghamshire, southern England. It was designed by Robert Stephenson, the L&BR's chief engineer and extended in the 1880s when the line was widened. It is a Grade II listed building.

Description
The bridge is an accommodation bridge, built to provide access to a farm after the road was severed by the construction of the railway. It has three elliptical arches in blue engineering brick which stand on piers of local coursed, squared limestone, faced with rock. The arches have substantial stone imposts and a stone course below parapet level. The parapets are in brick with a combination of stone and concrete coping. The much larger extension was built onto the end of the original. It has a pair of segmental arches almost entirely in blue brick. It has a broad stone roll cornice and a stepped parapet at the far end from the original bridge.

History
The original bridge was designed by Robert Stephenson, the chief engineer to the London and Birmingham Railway, and was opened at roughly the same time as the line in 1838. The extension was built between 1878 and 1882 when the L&BR's successor, the London and North Western Railway quadruple-tracked the line. At the same time, the line was diverted slightly to the east to allow for an extension of Wolverton Works. The cutting under the original bridge is now empty. the line is now the West Coast Main Line, which passes under the extension. The bridge has since been bypassed by a modern replacement and is now disused.

The original bridge is unusual among Stephenson's bridges in being built from stone rather than brick, likely material excavated from the cutting it spans. All other overbridges on this section of line were rebuilt in the 1950s when overhead electrification equipment was installed, making the Blue Bridge a possibly unique survivor. It is one of multiple surviving original L&BR bridges in the vicinity, including a bridge over the canal, that over Old Wolverton Road, and Wolverton Viaduct to the north of the town. The Blue Bridge has been a Grade II listed building 2001. Listed status provides legal protection from demolition or unsympathetic alteration.