Sir Donald Bailey Coleman graduated from the department in 1923 with a BEng. He then worked for the civil engineer’s department at the London, Midland and Scottish Railway and in the city engineer’s department in Sheffield before joining the War Office in 1928 as a civil engineering designer. One of his unit’s tasks was to develop improved transportable bridges for the army. In 1936, Bailey had the idea of a simple bridge structure that could be bolted together to suit the needs of the job in hand. It required no special tools or equipment to assemble and the elements were light and small enough to be transported in trucks and lifted into place by hand; each unit took six men to lift. Although it was light, the bridge would be strong enough to carry tanks and other armoured vehicles. Despite lack of interest from the War Office, Bailey continued to design the bridge in his own time and in February 1941, after their preferred bridge design failed testing, the War Office ordered him to design a new, all-purpose bridge. As he had done extensive work in his own time, the prototype was ready by May and bridge units reached the army in December. Over two thousand ‘Bailey’ bridges were erected in north-west Europe between June 1944 and May 1945 and allowed the army to mobilise their armoured and mechanised units, contributing to the allied forces' success. After the war, used and new bridge panels found a civilian market and many are still in use today including one over the River Don in Rotherham, the town where Bailey was born. Bailey was appointed OBE in 1944, knighted in 1946 and received an honorary DEng from the University of Sheffield the same year. He was a fellow of the Institution of Structural Engineers, a member of the Institution of Civil Engineers and an honorary member of the Institution of Royal Engineers.