EE WAS LYING ON TOP END PLATE ON LOOSE COAL STENCILING MARKINGS ONTO RAILCAR. HE LOST HIS FOOTING ON THE LOOSE COAL AND SLID DOWN A METAL SLOPE OF APPROX. 45 DEGREES FOR A DISTANCE OF ABOU T 6 TO 8 FEET. HE SUSTAINED A SPRAIN /STRAIN TO RIGHT KNEE AND SPINE ACCORDING TO MEDICAL EXAM. HE HAD BEEN INSTRUCTED TO ALWAYS USE A LADDER WHEN STENCILING.