Frank Griswold, a native of Minneapolis, was not only a prolific inventor, but a remarkable business man. Besides the Griswold Signal Company, the object of our interest, he founded a lubrication equipment manufacturer, a coffee vending machine company, a monorail operation, a beach hotel, a fly-in fishing lodge, and an aviation service company. He lived to the age of 96.

In the 1930’s he made his main contribution to railroad safety devices, the signal that bears his name. This unit combined a standard set of cross bucks and flasher lights with a rotating octagonal stop sign (referred to as a “banner”), and repeating gong. In the non-activated position, the stop sign presents an edge to on-coming traffic. When triggered, the lights begin to flash, the gong begins to sound, and the sign rotates 90º to display the normal stop aspect. These signs are most attractive, particularly when mounted on an optional cast base box.