The invention relates to a mobile device (2) for work on wheel sets, the device being mounted on rollers (10, 10') and being movable on a workshop rail system (11), for work on wheel sets (4, 6) rotatably mounted in a bogey, with the aid of a mobile wheel-set lathe (2), which can be connected to an associated service container (3), which likewise has been mounted on rollers (10) and can be moved on the workshop rail system (11), and a device (7) for supporting any wheel set (4, 6) which is present in the bogey and on which work is not being carried out. The mobile wheel-set lathe (2), the service container (3) and the device (7) for supporting the wheel sets (4, 6) have been mounted on a shared bearing support frame (9), arranged on rollers (10) which are movable in the workshop rail system (11).