To save cost and space.

An upper layer branched route 11 and a lower layer branched route 12 are separated in a maintenance station 1. A divided rail 28 lifted by a lifting rail 27 is joined to any one of the branched routes 11, 12. The divided rail 28 on which a conveying vehicle 7 is secured is lowered from the branched routes 11, 12, and joined to a loading/unloading rail 29. The loading/unloading rail 29 conveys the conveying vehicle 7 to the outside of the maintenance station 1, and conveys the conveying vehicle 7 into the maintenance station 1. The divided rail 28 on which the conveying vehicle 7 is secured is lifted from the loading/unloading rail 29 and joined to any of the branched routes 11, 12.

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