The invention relates to drive unit for driving at least one wheel drive shaft, especially, a wheelset axle, especially a cross-drive for use in rail vehicles. Said drive unit comprises a driving engine and a transmission assembly coupled thereto, as well as a braking system. The output of the transmission assembly is a hollow shaft that is coupled to the wheel drive shaft, especially the wheelset axle, via an articulated coupling. The invention is particularly characterized in that the braking system comprises two braking subsystems, namely a first braking subsystem and a second braking system. Said braking subsystems are embodied as disk brake systems that comprise at least one respective brake disk. A fastening flange for the brake disk of a braking subsystem is integral with the hollow shaft.