The invention further relates to an
estimation device (1) for determining a new
motion estimation value (vvirt) which indicates a speed of a rail vehicle (200) having at least two axles, comprising: a
Kalman filter (30) which applies at least torque values (mpi, mpi) on an input side; the torque values (mpi, mi), the
vertical force values (Qi), the wheel size values (ri) and the wheel rotational speed values (
omega i) are determined on the basis thereof and on the basis of Kalman filtering, a slip module (40) which applies the torque values (mpi, mi, mi) on the input side, and the slip module (40) determines a Kalman estimated vehicle speed value (vk) on the basis of the torque values (mpi, mi, mi). Mei), a wheel
size value (ri), a wheel rotational speed value ([
omega] i) and a respective previous
motion estimation value (vvirt) of the device (1) are estimated and a wheel circumferential speed value (vumauf) and slip information indicative of a possible slip of the respective axle are determined, and an evaluation module (50), and determining a new
motion estimation value (vvirt) of the
estimation device (1) on the basis of the Kalman estimated vehicle speed value (vk), the wheel circumferential speed value (vumauf) and the slip information.