Bailey bridge The Bailey bridge is a type of portable , pre - fabricated , truss bridge . It was developed by the British during World War II for military use and saw extensive use by both British and the American military engineer ing units . A Bailey bridge had the advantages of requiring no special tools or heavy equipment to construct . The wood and steel bridge elements were small and light enough to be carried in trucks and lifted into place by hand , without requiring the use of a crane . The bridges were strong enough to carry tank s . Bailey bridges continue to be extensively used in civil engineering construction projects and to provide temporary crossings for foot and vehicle traffic . History . Donald Bailey was a civil servant in the British War Office who tinkered with model bridges as a hobby . He presented one such model to his chiefs , who saw some merit in the design . A team of Royal Engineer ( RE ) officers was assembled at the Military Engineering Experimental Establishment ( MEXE ) , in Barrack Road Christchurch , Dorset , in 1941 and 1942 ; among them were Robin Foulkes , Darrell Herbert , John de Waele , and Bill Buckle , all R . E . subalterns at the time . In the course of development , the bridge was tested in several formats , e . g . , as a suspension bridge , and as a " stepped arch " bridge , as well as the flat truss bridge which became the standard . The prototype of this was used to span Mother Siller ' s Channel which cuts through the nearby Stanpit Marsh es , an area of marshland at the confluence of the River Avon ( Hampshire ) and the River Stour , Dorset . It remains there ( ) as a functioning bridge . Bridges in the other formats were built , temporarily , to cross the Avon and Stour in the meadows nearby . After successful development and testing , the bridge was taken into service by the Corps of Royal Engineers and first used in North Africa in 1942 . A number of bridges were available by 1944 for D - Day , when production was accelerated . The US also licensed the design and started rapid construction for their own use . Bailey was later knight ed for his invention , which continues to be widely produced and used today . The original design however , violated a patent on the Callender - Hamilton bridge . The designer of that bridge , A . M . Hamilton successfully applied to the Royal Commission on Awards to Inventors . The Bailey bridge however had several advantages over Hamilton ' s design . For example , damaged parts could not be replaced quickly on the Callender - Hamilton bridge , an essential requirement for military use . The Callender - Hamilton bridge was modified by the London County Council engineers ' department in the design of three emergency bridges which were erected across the River Thames in 1940 . Damaged parts of these could be quickly replaced . Experience gained in this work contributed to the development of the Bailey Bridge . Hamilton was awarded £4 , 000 in 1936 by the War Office for the use of his early bridges and the Royal Commission on Awards to Inventors awarded him £10 , 000 in 1954 for the use , mainly in Asia , of his later bridges . Lieutenant General Sir Giffard Le Quesne Martel was awarded £500 for infringement on the design of his box girder bridge , the Martel bridge . Design . The success of the Bailey bridge was due to its unique modular design , and the fact that one could be assembled with minimal aid from heavy equipment . Most , if not all , previous designs for military bridges required cranes to lift the pre - assembled bridge and lower it into place . The Bailey parts were made of standard steel alloys , and were simple enough that parts made at a number of different factories could be completely interchangeable . Each individual part could be carried by a small number of men , enabling army engineers to move more easily and more quickly than before , in preparing the way for troops and matériel advancing behind them . Finally , the modular design allowed engineers to build each bridge to be as long and as strong as needed , doubling or tripling up on the supportive side panels , or on the roadbed sections . The basic bridge consists of three main parts . The floor of the bridge consists of a number of transoms that run across the bridge , with stringers running between them on the bottom , forming a square . The bridge ' s strength is provided by the panels on the sides . The panels are , , cross - braced rectangles that each weigh , and can be lifted by six men . Transoms rest on the lower chord of the panels , and clamps hold them together . Stringers are placed on top of the completed structural frame , and wood planking is placed on top of the stringers to provide a roadbed . Ribands bolt the planking to the stringers . Later in the war , the wooden planking was covered by steel plates , which were more resistant to the damage caused by tank tracks . Each unit constructed in this fashion creates a single section of bridge , with a roadbed . After one section is complete it is typically pushed forward over rollers on the bridgehead , and another section built behind it . The two are then connected together with pins pounded into holes in the corners of the panels . For added strength several panels ( and transoms ) can be bolted on either side of the bridge , up to three . Another solution is to stack the panels vertically . With three panels across and two high , the Bailey Bridge can support tanks over a . Footways can be installed on the outside of the side - panels , the side - panels form an effective barrier between foot and vehicle traffic and allow pedestrians to safely use the bridge . A useful feature of the Bailey bridge is its ability to be launched from one side of a gap . In this system the front - most portion of the bridge is angled up with wedges into a " launching nose " and most of the bridge is left without the roadbed and ribands . The bridge is placed on rollers and simply pushed across the gap , using manpower or a truck or tracked vehicle , at which point the roller is removed ( with the help of jacks ) and the ribands and roadbed installed , along with any additional panels and transoms that might be needed . During World War II , Bailey bridge parts were made by companies with little previous experience of this kind of engineering . Although the parts were simple , they had to be precisely manufactured if they were fit each other correctly , so they were assembled into a test bridge at the factory to make sure of this . To do this efficiently , newly manufactured parts would be continuously added to the test bridge , while at the same time the far end of the test bridge was continuously dismantled and the parts dispatched to the end - users . Use in the Second World War . Stories of Bailey bridges being built and erected during the Second World War are legendary . The first operational Bailey Bridge was built by 237 Field Company R . E . over Medjerda River near Medjez el Bab in Tunisia on the night of 26 November 1942 . The very first instance of a Bailey being erected under fire was at Leonforte by members of the 3rd Field Company , Royal Canadian Engineers . In one instance a bridge was pushed over the Saar River while under artillery and tank fire . When the enemy was finally cleared out the panels had holes in them and would not carry the weight of a tank . Replacing the panels would require the bridge to be " broken " in the middle . Instead they simply bolted an entirely new set of panels onto the bridge on top of the original set , a technique that later became a standard feature . The Bailey provided an excellent solution to the problem of German and Italian armies destroying bridges as they retreated . By the end of the war , the US Fifth Army and British 8th Army had built over 3 , 000 Bailey bridges in Sicily and Italy alone , totaling over of bridge , at an average length of . One Bailey , built to replace the Sangro River bridge in Italy , spanned . Another on the Chindwin River in Burma , spanned . Such long bridges required support from either piers or pontoons . Field Marshal Bernard Montgomery wrote in 1947 : Modern Bailey bridges . Bailey bridges are in regular use throughout the world in the 21st century . Some exceptional examples include : Other uses . The Skylark launch tower at Woomera was built up of Bailey bridge components . In the years immediately following WWII , the Ontario Hydro - Electric Power Commission purchased huge amounts of war - surplus Bailey bridging , and established a small design group to promote its use in novel applications ; for example , the trestles required for an extensive gravel - classification set - up for the power plants then being built on the Ottawa River . After Hurricane Hazel in 1954 , some of the bridging was used to construct replacement bridges in the Toronto area . The Old Finch Avenue Bailey Bridge is the last still in use . Depiction in the media . The 1977 epic war film " A Bridge Too Far " , depicting the events of Operation Market Garden in September 1944 , has a lengthy scene showing the construction of a Bailey bridge at Son in the Netherlands by units of both the American 101st Airborne Division and the British XXX Corps .