Setting a trap on an overhead pipe. To support the trap, drill a hole in the trap base near the trigger or treadle and twist a wire around the pipe, leaving a short upstanding end. The hole in the trap is put over the wire end. A soft wire from the other end of the trap is fastened to some object below the runway. When sprung, the trap and rat will bounce off and hang from the wire, leaving the runway free for other rats to find other traps.

From Storer, T. I. 1960. How to Control Rats and Mice. Calif. Agric. Exp. Sta. Ext. Serv. Leaflet 127.