AI has this to say -
The Albion HJR is the classic and well-known vintage mid-1930s middle-weight Albion gearbox featuring 3 forward speeds
and 1 reverse gear, commonly used in motorized three-wheel delivery carriers, light agricultural auto-trucks, and cyclecars.
I think I've seen one in a light car at a show someplace
Hence the reverse gear
If you pay them enough, someone is sure to take it off your hands !!