Two electricians/journeyman mechanics were doing preventative maintenance on a high-density storage system, an aisle with two cranes. They were preparing to lubricate the chains on one of the cranes. One of them was on the lift station, seated above the crane on a cross-support bar to perform lubrication and test the vertical limit switch. He tripped the vertical limit switch to begin the work. The crane and the lift station began to move up, and his right leg was pinned and broken between the frame of the crane and the crossbar of the lift station.