A material-handler adapted for locating on top of an open topped railroad car includes a chassis mounted on tracks, and a first and second pair of outriggers extending from the chassis. Wheels and clamps are located at the distal ends of the outriggers to stabilize the material handler on the top of the railroad car. A knuckle boom is rotatably mounted on the chassis for manipulating cargo materials. The material handler of the invention also utilizes the clamps and wheels on the outriggers in conjunction with the boom to self-load and self-unload the material handler to and from the top of a railroad car, and to and from one care to another with possible different height and width. Operator safety is enhanced by allowing the operator to control the self-loading and unloading via remote control.