Lyne Bridge

M25 Junction 12

This is a distinctive cable-stayed railway bridge, which crosses the M25 immediately south of that motorway’s connection with the M3 at Junction 12. The bridge takes its name from the village of Lyne, Surrey, the eastern fringe of which borders the M25, and upon its reinforced concrete deck is carried the double-track “Chertsey Loop”. The latter links the Waterloo Main Line at Weybridge with the route to Reading via Staines at Virginia Water, and is about 5½-miles in length with intermediate stops at Addlestone and Chertsey.

The bridge’s construction formed one of the earliest parts of the works to build the Thorpe to Chertsey section of the M25. In June 1976, the project began with the slewing of the railway line onto available land adjacent to the construction site, so the then new bridge could be built in situ to minimise disruption to trains. The contract for this realignment had been awarded to “John Mowlem & Co Ltd” earlier that year (ref: Concrete Society, 1979). The £903,700 contract to build the bridge itself was awarded to “Redpath Dorman Long”, the company of which arrived on site in March 1977 (ref: New Civil Engineer, 1978). The design of the structure was the work of “Stressed Concrete Design Ltd”, which worked in collaboration with J. B. Manson, the then Chief Civil Engineer of British Rail’s Southern Region.

The most striking features of the bridge are the pair of tapered towers of reinforced concrete construction. The towers are 22.04 metres high when measured from the upper side of the bridge’s deck; the sides of the latter are 2.76-metres-high, and the reinforced concrete supporting pillars below, rising up from the central reservation of the M25, are 5.30-metres high. Each tower has eight cable stays linking them with the bridge's deck. Each cable stay comprises 79 wires of 7mm diameter and is affixed to the bridge’s deck by twelve 32mm-diameter bars. The bridge diagonally crosses over the M25 at an angle of 28 degrees, extending to an overall length of 117.44 metres and a width of 11.56 metres (ref: Cable Stayed Bridges, R. Walther, 1999).

Lyne Bridge was formally opened by the then Chairman of British Rail, Sir Peter Parker, on 7th February 1979, and the first trains used it on 12th of the same month (ref: The Railway Magazine, April 1979). This was the only cable-stayed railway bridge in Europe at the time, and the section of M25 between Thorpe and Chertsey was opened to the public on 9th October 1980.

9th September 2022

A northward view on the approach to Junction 12 of the M25, travelling clockwise, shows to good effect the angled nature of the bridge over the motorway. Virginia Water is to the left; Chertsey, Addlestone, and the Waterloo Main Line are to the right. © Magdalena Pacyk

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