IIRC the Glenn Miller record uses the original grade crossing signal in the intro - two longs / two shorts. The record was made about the time it was changed to the still-used two longs / one short / one long.
I grew up across the street from a railroad line. Back when I was a kid in the sixties, one (I'm guessing old-timer) engineer used to do sort of a hybrid - two longs / two shorts / then one long to finish.
