To maintain and inspect drivers for rolling stocks different in shape and weight on the same maintenance line.

An AGV40 can shift on a travel line 17 made in loop form. An air spray 68 and a groove cutter 74 are provided in the loop of the travel line. A conveyor means, which transfers an MM98 or an MG99 mounted on the AGV to the air spray, is provided between the air spray and the travelling track. This maintenance line is provided with a first transfer line which is provided with a storage conveyor, a branch conveyor 60 capable of shifting a loaded MM or MG in two different directions, and a turn table being capable of converting the direction of the loaded MM or MG and for transferring it to a groove cutter in the shape of a straight line, and a second transfer line which has a storage conveyor and a brunch conveyor in parallel with this first transfer line. It is transferred, using the first transfer line in the case of MM, and using the second transfer line in the case of MG.