Locomotive maintenance is the main traffic department of railway transportation system, which is mainly responsible for the operation, comprehensive maintenance and overall maintenance of railway locomotives (generally medium maintenance and section maintenance). They are "train drivers" and "train mechanics". Belongs to the first-line drive unit. The locomotive depot is generally located near an important railway hub city or an important freight marshalling station, and is mainly responsible for the power traction task or special transportation task of passenger trains, cargo trains and baggage trains. The Locomotive Depot of the Transportation Bureau of China Railway Corporation is the highest-level unit of the railway locomotive system, which consists of locomotive depts of various railway bureaus (companies). Each locomotive depot consists of several locomotives, and each locomotive depot consists of several locomotive workshops and locomotive return sections. There are also maintenance workshops, maintenance workshops, equipment workshops and functional departments.