An electromechanical motor includes a rail to be moved, a dry, non-lubricated, sliding bearing for the rail, and driving members imposing a mechanical driving force on the rail. The bearing has two rail contacting portions. A first portion contacts the rail for obstructing displacements of the rail in a first direction transverse to a main extension of the rail. The first portion also obstructs rotation of the rail around an axis parallel to the main extension. The second portion is arranged for obstructing displacements of the rail in the first direction transverse to the main extension, while allowing at least a minor movement of at least one of rotation of the rail. The motor allows for mechanical flexibility at certain selected positions and ensures immobility at other selected positions, in order to reduce the impact of externally induced displacements, torques and rotations at critical places in the motor.