The invention relates to a gantry crane of a machine, for the exchange of sleepers on a track, which may be displaced in a machine longitudinal direction on crane tracks. Two crane buggies on the gantry crane, at a separation from each other in the machine transverse direction are embodied such as to be displaced relative to the crane chassis by means of a displacement drive for altering the gauge. The corresponding crane tracks may be adjusted in the track transverse direction by drives to change the gauge.