Development of a temporary flyover: "The Carbridge"
|Location||National Archives (see all files stored here)|
|File base||Series MT, subseries MT 95|
In around 1960, a delegation visited the MOT with a proposal for a system of generic metal flyover components that could be assembled in unlimited combinations to construct single-lane temporary flyovers, able to carry vehicles up to the size of a double decker bus. The system was known as the Carbridge, and its inventor, Major Stralogo, sent in a set of engineering plans and a large number of drawings showing where they could be built. (One fabulous design was for a signalised junction on the A3 Kingston Bypass, where he proposed two Carbridge flyovers for A3 traffic in what were then the verges, diverting through traffic on the A3 over to the far left side of the carriageway, into the cycle path, to join the flyover and cross the side road.)
The MOT was sufficiently interested to agree to the construction of a prototype, which was built at Camp Hill in Birmingham. This was supposed to last about ten years, and Stralogo hoped that it would then be dismantled for use elsewhere, but of course it stayed there until the late 1980s when it was demolished and replaced with the traffic lights that are still there now.
One of the most interesting points from this file is that no more Carbridges appear to have been built - other temporary flyovers that came later, such as the Army and Navy at Colchester, Hogarth in West London and so on, were to bespoke designs and were not to Stralogo's designs.
People with camera copies
Chris Marshall has a partial copy.