Study on Process Design of EMU Depot Combining Overhaul and Depot Repair

Conventional locomotives and vehicles need to be transported to locomotive and vehicle manufacturing factories for large repair or overhaul from railway bureaus after they have attained a certain traveling mileage or run a certain number of years. Transporting locomotives and vehicles between railway bureaus and manufacturing factories for repair wastes the carrying capacity of railway lines, interferes with railway operation, and extends maintenance time. Besides, the maintenance time of EMUs needs to be minimised because of the high cost of EMUs. In summary, an EMU maintenance base (EMU depot) that combines overhaul and depot repair needs to be investigated. The process design of an EMU depot needs to be compatible with the maintenance of different types of EMUs, and the efficiency of the EMU depot needs to be improved. In order to solve the abovementioned problems, the general layout scheme and choice of land block of the EMU depot are studied. In addition, a scheme of underfloor vehicle-lifting machines for CRH2 and CRH3 EMU level 3 maintenance (depot repair) is studied. Finally, the efficient completion of a successive maintenance scheme for level 4 and 5 maintenance of a vehicle is presented. According to the design scheme presented herein, the combination of the overhaul and depot repair is first realised. In addition, the length of the vehicle-lifting elements of the machine can be adjusted within a range of 17. 375-17. 500 m, which achieves compatibility with the level 3 maintenance of CRH2 and CRH3 EMU. Further, the designed maintenance line is applicable to not only two eight-car EMUs but also a 16-car EMU. Moreover, level 4 and 5 maintenance of a vehicle can be completed within 80 min. With the proposed scheme, the specialisation of every maintenance station and process can be realised. The cross operation among different maintenance groups is avoided. A clean assembly station of car body parts is guaranteed, and maintenance efficiency and quality are improved.