HAD RAIL CAR WRECKED IN BOOSTER DRIVE AREA AT #21 BREAK. HAD RAIL CAR JACKED UP AND WAS GOING TO PULL CAR OVER WITH 3/4 TON COME ALONGS. HOOKED UP TO A SHACKLE ON A RIB BOLT. WHEN PRESSURE FROM THE COME ALONGS LOOSENED PLATE, A PIECE OF RIB ROLLED OUT & STRUCK EE ON THE OUTSIDE OF THE RT. LEG.