Sir Donald Bailey(1901–1985)

Donald Coleman Bailey was born at Rotherham in the West Riding of Yorkshire on the fifteenth of September 1901, son of an iron-foundry engineer of the Rotherham steel-and-iron district. He was schooled at Rotherham Grammar, took the engineering degree at the University of Sheffield in 1923, and joined the War Office Experimental Bridging Establishment at Christchurch in Hampshire as a junior civilian engineer in 1928. He stayed at Christchurch for the next twenty-one years and rose through the long inter-war seniority to Deputy Chief Engineer by the outbreak of war in 1939.

The standard British military bridge of the late 1930s was the box-girder Inglis bridge of the 1920s, a heavy welded structure requiring crane assembly and accessible by road only. Bailey had begun working on an improved design through the late 1930s on his own initiative, sketched the first plan of his modular box-section design on the back of an envelope on a War Office train journey in February 1941, presented it to his Director Sir Bertram Hopkinson in May 1941, and on Hopkinson's order put the first prototype into manufacture at Christchurch over the summer of 1941. The first Bailey bridge was tested at Christchurch on the thirty-first of December 1941 and accepted into Royal Engineers service in March 1942.

The Bailey bridge of 1942 was a ten-foot panel of welded steel pin-jointed at the corners, designed so that any number of panels could be bolted side-by-side to widen the bridge and stacked one on top of another to deepen the trusses to carry any required load. The standard component weighed less than two hundred and fifty kilograms (it could be carried by six men), the full bridge was launched on rollers from one bank under its own counterweight without cranes, and the design permitted the field engineer to build any span from twenty to two hundred feet by selecting the required panel-and-stack combination. The system was perfectly suited to the rapid river crossings of the Eighth Army's advance through North Africa in 1942 to 1943, the Italian campaign of 1943 to 1945, and the north-west European campaign of 1944 to 1945.

Over two thousand Bailey bridges were erected by the Royal Engineers across the European, Italian and Pacific theatres of the Second World War. The Anglo-American Engineering Corps built fifteen hundred Bailey bridges across the Rhine and the Rivers Po, Reno and Tiber alone in the eighteen months from June 1944. Field Marshal Bernard Montgomery, in his personal account of the campaign, judged the Bailey bridge the single most important British engineering contribution to the war effort. Bailey was knighted in 1946 (the first English engineer knighted on the strength of a Second World War contribution), was made an OBE in 1942, was awarded the Telford Medal of the Institution of Civil Engineers in 1944, and continued at Christchurch as Director of the renamed Military Engineering Experimental Establishment from 1945 to 1966. He died at Bournemouth on the fifth of May 1985 in his eighty-fourth year. The Bailey bridge design remained in continuous Royal Engineers service for the next seventy years and is still produced today by Mabey Bridge of Lydney for the international civilian disaster-relief market. The Bailey name in modern military engineering carries the weight of the back-of-envelope design of February 1941.