Running gear unit for a vehicle, in particular a rail vehicle, with - a motor holding device, especially a running gear frame, and - a fastening device for a traction motor unit connectable to the motor holding device, wherein - the motor holding device defines a longitudinal direction in the direction of travel, a transverse direction, a height direction, and defines an upper side and a lower side (103.4) in the height direction, - the motor holding device is designed to be supported, in the height direction, on at least one wheel unit to be driven by the traction motor unit, - the fastening device is configured to substantially rigidly support, in the height direction, the traction motor unit at the motor holding device via at least one positive connection, - the fastening device is configured such that, for mounting the traction motor unit to the motor holding device, the traction motor unit is insertable into the motor holding device on a mounting path, in particular from the lower side (103.4) of the motor holding device, - the fastening device has at least one fastening element which can be brought into engagement with the motor holding device and the traction motor unit, wherein - the fastening element, when the traction motor unit is located in the support position, is movable into a locking position in a locking direction transverse to the mounting direction, wherein - the fastening element, in the locking position, for supporting the traction motor unit in the height direction, cooperates with the motor holding device via a first positive connection acting in the height direction and cooperates with the traction motor unit and via a second positive connection acting in the height direction, characterized in that - the first positive connection is formed via a projection (103.2) on the motor holding device which engages an associated first recess (106.1) in the fastening element, - the second positive connection is formed via a projection (104.2) on the traction motor unit which engages an associated second recess (106.2) in the fastening element, - the recesses (106.1, 106.2) are formed in the manner of a groove, and - the fastening element is substantially S-shaped with the first recess (106.1) and second recess (106.2) substantially facing away from each other. - a motor holding device, especially a running gear frame, and - a fastening device for a traction motor unit connectable to the motor holding device, wherein - the motor holding device defines a longitudinal direction in the direction of travel, a transverse direction, a height direction, and defines an upper side and a lower side (103.4) in the height direction, - the motor holding device is designed to be supported, in the height direction, on at least one wheel unit to be driven by the traction motor unit, - the fastening device is configured to substantially rigidly support, in the height direction, the traction motor unit at the motor holding device via at least one positive connection, - the fastening device is configured such that, for mounting the traction motor unit to the motor holding device, the traction motor unit is insertable into the motor holding device on a mounting path, in particular from the lower side (103.4) of the motor holding device, - the fastening device has at least one fastening element which can be brought into engagement with the motor holding device and the traction motor unit, wherein - the fastening element, when the traction motor unit is located in the support position, is movable into a locking position in a locking direction transverse to the mounting direction, wherein - the fastening element, in the locking position, for supporting the traction motor unit in the height direction, cooperates with the motor holding device via a first positive connection acting in the height direction and cooperates with the traction motor unit and via a second positive connection acting in the height direction, - the first positive connection is formed via a projection (103.2) on the motor holding device which engages an associated first recess (106.1) in the fastening element, - the second positive connection is formed via a projection (104.2) on the traction motor unit which engages an associated second recess (106.2) in the fastening element, - the recesses (106.1, 106.2) are formed in the manner of a groove, and - the fastening element is substantially S-shaped with the first recess (106.1) and second recess (106.2) substantially facing away from each other.