Esk Valley (North Yorkshire) Railway Bridges
The railway routes in the area had to contend with the meanderings of the River Esk, necessitating numerous bridges.
These included a series of six similar viaducts of interesting construction, built in 1864. They had a combination of masonry arches with an iron span over the river. The point of interest was the hog-back wrought iron main girders whose top flanges were assembled from iron castings. In 1926 the iron girder spans were strengthened by the insertion of a deep single steel plate girder located centrally below the deck. Stiffening steelwork was also attached to the top chords, presumably at the same time. One iron span, on the North York Moors Railway (NYMR), was replaced in 2010, and by 2012 another was disused. The other four, on Network Rail's Esk Valley Line, have now been replaced[1]. The latter four are listed as Danby, Duck, Thorneywaite and Carr End.[2]
It is known that five of the six iron girder bridges have been replaced in recent years, but it is not known whether the other still exists. It would be a great pity if they have all been scapped. The use of cast iron for the top chord members of wrought iron plate girders was rare, and there are very few known survivors (specifically, two: Arpley Bridge, Warrington and Half Moon Lane Bridge (Gateshead). Those have box section girders, whereas the Esk Valley bridges have single thicknesses of plate. It appears from photographs that the Esk Valley bridge iron castings are of 'L' or 'T' cross-section, sandwiching the main web plates. This is speculative, as the tops of the castings had been covered by riveted steel stiffening plates.
See photos of NYMR Bridge 30 here and here.
A small cast iron bridge made by Head, Ashby and Co in 1863 has been removed from service and is currently stored at Beamish[3]
1865 Pickering and Whitby Deviation Railway.— This new line, by which the long incline in Goathland will be superseded, and a fruitful source of accident avoided, is expected to be ready by the commencement of the summer season. The line would have been in operation now, but it was discovered that the iron girder bridges (which are numerous) were too light; indeed, one snapped under the pressure of a heavy engine. The North Eastern Board, therefore condemned the whole of the bridges, which are now being replaced by much stronger structures. The extension of the North Yorkshire Railway from Castleton to Grosmont will be ready for opening about the same time, and the two lines will together afford the towns of Pickering and Whitby, and the whole of the East Riding, another, and, in many cases, shorter route to Guisbro', Stokesley, Stockton, and tho north.'[4]
1865 'The Deviation on the Whitby Railway. —The travelling public generally will be glad to know that the present week will terminate the use of the dangerous portion of the Malton and Whitby Railway known as the "Goathland Incline." The construction of the deviation line was let to Mr. Thomas Nelson of Carlisle, who ought to have had it ready twelve months ago, but the difficulties to be overcome have been so great that the year's delay, with safety, could not be avoided. The ground proved treacherous in the extreme — the banks would slip away from under the workmen's feet, and the cuttings filled again as fast they were made. Added to these obstacles was engineering miscalculation, by which five out of the six arched girder bridges of plate-iron, bolted together, had to be taken down and replaced by stronger ones — one of the first giving under the contractor's engine tho first time it was run on it, engine and bridge going down into the stream Thn new line leaves the old one just after passing the Fen Bogs, which are at the head of the romantic pass of Newton Dale. ....'[5]