EE attempting to step down from Ballast Loading Dock to track level(approx. 26"" verticle drop in elevation). Lost footing causing him to fall backward. Attempted to brace fall by extending right arm/hand to contact ground on loading dock. When hand contacted ground, EE felt pain in right arm. Completed shift. Saw DR. 11-25-08. Rx prescribed, X-ray & MRI ordered. Restricted Duty