GWR Route: North Warwickshire Line

Danzey for Tanworth Station: gwrdt1371

View of an extremely skewed plate girder underbridge built in 1906 to carry the Birmingham & North Warwickshire Railway over a minor road (Ramshill Lane) south of Danzey for Tanworth. The photograph was taken in 1958, but the structure is the original and remains in use today.

The steel plate girder design was typical for the period, being considered to be the most economic for spans from 15 to 80 foot. The type used here is termed a ‘through bridge’ with cross girders supported on the lower girder flange of the main girders to maximise the road headroom below. In this case, due to the extreme skew some of the cross girders are supported on one side directly on the brick abutments and this also meant that only two outer main girders were necessary. The arrangement gave a road headroom of twelve foot, six inches at this location. Conventional construction has smaller steel girders acting as rail bearers on or between the cross girders positioned directly under each rail of each track. The width was then covered with waterproofed steel decking plates, with vertical ballast plates either side, and on this the ballast and track formation was placed. Later in the 1920’s, transverse pressed steel troughing had largely replaced this cross girder design on through plate girder bridges. Close inspection will show that the main girder flange is thicker at the centre of the span where the bending stress is greater, because a number of additional (double) flange plates have been riveted together at this position to give extra strength. There will be bedplates under the girders at each end and in this case under those cross girders that rest on the abutment. Bedstones are built into the abutments to provide a harder surface under the girders. The main girders have vertical stiffeners at regular intervals to prevent buckling occurring.

The steel plate girders for this bridge at Danzey were manufactured by E C & J Keays Ltd of Darlaston and has a cast iron plate bearing their trade mark and the date in the centre panel. The abutments, wing walls and pilasters were constructed from blue engineering brick by the main contractor C J Willis & Sons.

Robert Ferris

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