1944 Darley catalog page dscribing their Simplex C-811 signal "the most popular in America." It sold for $87.50 complete. Now you're lucky to get one in good condition for $800.00.
I can remember these signals as a kid. (Yeah, I'm old.) And it was scary when a bulb went out. However the law was strict back then. If a signal wasn't lit you stopped until it was safe to proceed or you got a ticket. It's still that way but not so strictly enforced. Back then a lot of beacons flashed yellow in all four directions. Nowdays that would produce a pile up for sure!