MRFS wrote:I'm also convinced that's a gas fitment - the large round thing is a filter, I think.
There were *flashing* gas lit signals. Yep, extinguishing and relighting the flame. Eek.
But this wasn't town gas technology.
Flashing gas lit signals used acetylene gas and AGA lamp technology. This was invented by Gustav Dahlen for use in unattended navigation lights. It was consequently *very* *very* reliable - railway signalling doesn't even come close. Navigation lights simply can't go out, nor is there a signal maintenance technician on call to fix them if they do. A couple of times a year, the supply ship would turn up, the crew would clean the bird poo off the light, change the acetylene bottles, service everything, and depart.
The complete system included a 'sun valve' which turned the light off during daylight hours, and valves that made it flash. The flashing is important - each light has a 'characteristic,' or particular pattern of flashes, so that mariners can reliably distinguish one light from another at night. And, yes, the gas was cut off and relit every time using a pilot flame. Dahlen, incidentally, won a Nobel prize for physics for the invention of the sun value.