A device for screwing and unscrewing bolts and screws uses a motor-driven screwdriving tool, which is preferably used in the track region of railroad facilities. The device makes it possible to screw and unscrew screws, nuts and bolts reliably and effectively, preferably in the context of railroad use. The appliance is intended to have a low weight and a high output over long periods of use, can be operated with one hand, is specifically pre-oriented to the various applications and has a modular construction. To this end, the device has a central rib which serves as a receptacle for all of the attachments and fittings to be installed in a modular manner.