The EE was helping put a tram motor that had de-railed back onto the track. They were using a lever hoist, air bags, and a lifting jack to hoist the motor back onto rails. The EE was assisting with the jack bar as another EE was jacking with the lift jack. The lever hoist slipped, shifting the weight back to the jack motor, motor landed on EE's right leg. EE able to pull leg out.