EMPLOYEE WAS USING A STEEL BAR TO SET THE SECURITY LATCH ON THE BOTTOM DOOR OF A RAILCAR HE HAD HELPED UNLOAD. WHEN HE PULLED BACK ON THE BAR ITSLIPPED OUT OF IT'S PURCHASE POINT AND HE STUMBL ED BACKWARDS AND FELL ON HIS BUTT. THE DOCTOR PUT HIM ON RESTRICTED DUTY. HE DID NOT REPORT FOR HIS NEXT SHIFT CLAIMING HE HURT TOO MUCH. HE WORKED OCT 16&17 BUT NOT THE 18TH & IS STILL OUT.