That's a rare one, for sure. It was basically three WABCO E-2's put together to compete with the Leslie and Nathan three chime horns. The E-2 was the common single trumpet horn that was used on the sides of so many early Geeps. From my research, only a few of these were sold, and they were used exclusively by US armed forces locomotives, mostly GE 65 tonners and export RS-1's.
