Railway maintenance machine for track levelling and alignment, with the capacity to operate without interruptions to its advance on straight tracks, to operate on track turnouts, and with the capacity to tamp the diverging track, characterised in that it comprises a lifting and slewing unit with a duplicated power system at the front end and at the rear end of said unit, where the lifting and slewing unit comprises a lifting trolley (21), with two pairs of hydraulic cylinders (27A and 27B) arranged so as to exert force to lift the track, and a slewing trolley (20) with two pairs of hydraulic cylinders (28A and 28B), arranged so as to exert force to modify the lateral position of the track, where said power system at the front end exerts force to carry out approximately 80% of the levelling and alignment needed by the track and where said power system at the rear end exerts force to carry out the rest of the levelling and alignment needed by the track to reach its definitive position.