The efficient running of the North-east Indian railways during World War II became critical to the success of the Allied war effort in the South-East Asian Theatre. At the start of the War the railways and water communications of north-east Indian Railways was not a major concern for the British Empire forces stationed in Burma as they could be supplied by sea through port in Rangoon (as could Chinese forces in south western China thought supplies passing up the Burma Road). However, when the Japanese attacked and forced the British back to the Indian Burmese border, the supply of material over the extended lines of communication from Calcutta to the front lines and over the Hump into China, became a critical issue for the Western Allies and the Chinese National Revolutionary Army (NRA) under the command of Generalissimo Chiang Kai-shek. War time expediency, investment and ingenuity increased rail tonnage from around 600 tonnes a day to over 7,300 by January 1946. History In the initial phase of the war the Japanese advanced north from Rangoon through Burma forcing Allied forces to retreat into the mountains on the Indian Burma frontier. In doing so, not only did the Japanese threaten India, but they denied use of the Burma Road to the Western Allies, who had been sending supplies to Chiang Kai-shek's National Revolutionary Army (NRA) by that route. Behind this frontier, there was a series of railways in India which were essential to supply the Allied armies with logistics. They ran from the port of Calcutta to the hill station of Ledo in Assam. These logistics were not only needed by the British Fourteenth Army, and the American and Chinese troops at the end of the line under the command of General Joseph Stilwell's Northern Combat Area Command, but also Allied forces in China. Allied forces in China consisted of Chiang Kai-shek's NRA, and American units based in China such as those involved in Operation Matterhorn. Allied forces in China were supplied by an airlift, over the Hump of the Himalayas, from the airfields (Ledo Airfield and perhaps few other) built close to the north east end of the railway, towards the end of the war this was supplemented by the use of the newly built Ledo Road which started close to the railhead in Ledo. From port of Calcutta a broad gauge railway ran for to Parbatipur. Here goods had