A soft target movement platform (1) which comprises at least one drive unit (11), each unit having a motor carrier (12). The drive motor (21) is preferably journaled in the motor carrier about an axis central and longitudinal of the motor. A drive wheel (6) is drivingly connected to the drive motor, with the wheel's axis of rotation offset from the central longitudinal axis by a lever arm (31). The lever arm having a horizontal extent in use, whereby wheel load tends to rotate the motor with respect to the carrier about the longitudinal axis. A spring (32) acting between the drive motor and the carrier counteracts the wheel load rotation.