An employee was attempting to pull a dry skid off a trailer and onto a rail gate (a moving platform that freight is loaded onto) with a pump jack. The rail gate was slippery from the previous day's snow. He got onto the platform of the rail gate and turned the handle of the pump jack to stop its movement, but the pump jack kept sliding toward him. As he tried to get out of the way, he fell approximately 4 to 5 feet to the ground. He suffered a cut over the left eye, bruised ribs, and a crushed left elbow.