Mechanical workshop, Samastipur was established in 1881 for overhauling of Steam locomotives, POH of coaches and wagons. It originally belonged to Bengal &
North Western Railway (BNWR) and subsequently merged in state owned Oudh Tirhut Railway (OTR) on 1
st April 1943. Later on, after formation of zones, it became a workshop of North Eastern Railway. Subsequent to restructuring of zonal Railways, it has come under East Central Railway. At present, this workshop manufactures BOXNHL wagons. The workshop is also ISO 9001:2008 certified.