A mobile installation for loading, transporting and unloading track parts such as ties on, in and from open top railroad cars including a train mounted for mobility along a railroad track and having a plurality of open top railroad cars. Adjacent ones of the railroad cars are coupled together and each one of the railroad cars has two parallel side walls with top edges extending in the direction of the railroad track, and two end walls, the end wals of the adjacent railroad cars defining respective gaps therebetween. A power-driven crane is provided for loading and unloading the track parts and has an undercarriage supporting the crane for mobility in the direction of the railroad track. There is also a track supporting the undercarriage of the crane for mobility above the top edges of the railroad cars in said direction. The track includes two parallel guide rails mounted on the top edges of the railroad cars and is spaced apart a distance corresponding to the gage of the crane undercarriage. The guide rails extend beyond the end walls of the railroad cars into the gaps between the adjacent cars to provide a substantially continuous track for support of the crane undercarriage along the train of cars. The power-driven crane comprises a pivotal overhead outrigger and another outrigger mounted for mobility on the guide rails, the other outrigger carries an endless conveyor band for receiving and storing the track parts. A bridge-like gantry crane is mounted for mobility on the guide rails, the gantry crane includes means for loading the track parts on, and unloading the track parts from, the endless conveyor band.