2 employees where moving a sulphur tray from under a rail car. EE1 was pulling by holding onto the tray. EE2 was squatting pulling by a rope handle. They said the rope handle broke, and EE2 fell backward on rear then back. EE2 called supervisor to explain what happened, and that lower back hurt. At the clinic they said elbow hurt also, and they found a hairline fracture.