Abstract: The railcar includes: an operating unit provided with equipment for removing the old tracks and with supporting elements for advancing on the old sleepers stripped of their tracks, and, in sequence: first elements for gripping the old sleepers, capable of executing controlled cyclic oscillatory and vertical movements to grip the old sleepers, for removing them from their original seat and depositing them on a removal conveyor; a rotary operating element, capable of executing controlled cyclic oscillatory and vertical movements for the prearrangement of each seat stripped of its related old sleeper; at least one strike element, susceptible to longitudinal motion with respect to the frame of the operating unit and subject to fluid actuated control elements for the compaction of the new laying plane in each prepared seat; second grip elements, capable of executing controlled cyclic oscillatory and vertical movements for controllably resting them on the laying plane of each regenerated and compacted seat; and str