A Famous Railway Bridge.

Eighty years ago a new link between the counties of Devon and Cornwall was effected by the opening of the Royal Albert Bridge, Saltash, carrying the Great Western Railway over the estuary of the River Tamar. The Saltash Bridge is one of the most remarkable engineering structures on the Home lines, and it was designed by the G. W. Company's famous first engineer, Isambard Kingdom Brunel. The bridge is 2,220 feet in length, and in addition to the two main spans of 455 feet each, there are seventeen land spans varying from 70 to 90 feet each which, on the Cornish side, are on a sharp curve. The height of the central pier is 240 feet from the foundation, and the railway is 110 feet above high-water level. Brunel's original scheme provided for a structure with a main span of 255 feet and six others each of 105 feet. Unfortunately, however, the Admiralty stepped in, and insisted on a headway of 100 feet above high water. After toying with a novel plan for a bridge with a single main span of 850 feet, Brunel at last evolved the design of the bridge as we know it today. Because of a thick bed of mud beneath 70 ft. of water in the centre of the river, it took two years to construct the central pier. The two main trusses were built up on the Devonshire shore, and erected in position in 1857 and 1858. Each truss consists of an arch-shaped wroughtiron tube, of oval section, 16 ft. 9 in. wide and 12 ft. 3 in. high, the ends being connected by a suspension chain of link plates. The arch and chain are connected at eleven points in the truss by verticals, themselves braced together by means of diagonal bars. From these verticals there hang girders supporting the roadway. Each truss is 56 ft. high at centre, and weighs 1,060 tons. Comparatively little alteration or strengthening of the Saltash Bridge has been called for throughout its eighty years of service, and it is fitting that the genius of its designer should be marked by an inscription in raised letters on the landspan archways: “I. K. Brunel, Engineer, 1859,” this latter being the year of his death.