Keadby's Moveable Bridges

Keadby in Lincolnshire, England, a tiny village, known mainly for its gas-fired power station, has, in addition to a unique (in Europe) sliding rail bridge over the Stainforth and Keadby Canal, two swing road bridges over the same waterway and an impressive rolling bascule bridge over the River Trent. For fans of the interface between civil and mechanical engineering this is a place of pilgrimage. 

 A sliding bridge, or thrust bridge, is very rare. Few have ever been built in the world (because of the required land take which must be available). In operation the entire bridge is bodily moved sideways to remove the obstruction to passage below it, usually boat traffic as in this case. There has been a sliding bridge at Keadby since 1925 (when it replaced the 1860s swing bridge) and the current one is the 2024 upgrade of the original (largely by replacing wooden beams with metal supports). The bridge crosses the canal diagonally and when it moves to open the canal route it maintains an alignment parallel to the rail track. To see it in operation is an amazing sight (and the only real way to understand how it works) but it is totally unpredictable as to when it will occur. 

 The powered swing bridge over the canal (Keadby Lock Swing Bridge) is a pretty standard swing bridge which carries the minor B1392 road from Keadby to Eastoft, where it meets the A18 to Goole. The canal continues for about 250 yards through locks and into the River Trent. The swing bridge was originally installed in 1802, replacing another swing bridge, slightly downstream, which had been there since 1793. The old bridge abutments are still in place.

 In isolation, the Keadby Lock Swing Bridge is not particularly unusual and, in fact, there are several swing bridges on the Stainforth and Keadby Canal (including the human muscle-powered Vazon Swing Bridge just upstream of the sliding bridge). However, the impressive bascule bridge over the tidal River Trent is another matter. This bridge has been correctly called a giant sculpture.  Correctly known as the King George V Bridge, it is a very large rolling bascule bridge (sometimes called a Scherzer rolling lift bridge). It was built between 1912 and 1916 by the Great Central Railway, replacing a previous swing bridge constructed by the South Yorks Railway in 1864. It carries both a double-track railroad and the A18 road.

Its 163 ft electrically-powered bascule was one of the first of its kind in the UK and, at the time it was constructed, was the largest in Europe. It was designed by James Ball and C A Rowlandson. The construction contractors were Sir William Arrol and Co. It has three main spans and two approach spans. It was the eastern main span, which lifted. The bascule rolled and rotated on a large counterbalance. Originally powered by a large storage battery charged by on-site petrol-driven generators, it was later connected to mains electricity. Unfortunately, the bridge has not lifted since 1956. The most famous bridge of this type is probably the Pegasus Bridge in Normandy (https://www.atlasobscura.com/places/memorial-pegasus-and-pegasus-bridge). 

The close proximity of four moving bridges, of three different types, makes Keadby very special. Inclusion of the sliding rail bridge makes it unique.