The Bicester Military Railway (BMR) is a railway in Oxfordshire, England belonging to the Ministry of Defence. It links military depots at Piddington, Arncott and Graven Hill with the Oxford to Bicester Line. The line has no road bridges. All of its crossings of public roads at Ambrosden, Arncott and between Arncott and Piddington are by level crossings. The Bicester Military Railway was built in 1941 within the Bicester Central Ordnance Depot and was used extensively in the Second World War.