Re: Question...

I do not have a Rio Grande rule book; but, I have Southern Pacific Operating Department rule books from the 1898 and 1903, and a Oregon Short Line from 1907 (covering SP east of Sparks).

All of these state that three short (o o o) whistle signals indicate that a standing locomotive will back up. This is to be given in response to hand, lantern, or air-whistle or bell-cord signal to back up a standing locomotive or train.

All of these state that two short (o o) whistle signals is to be given as a response to any signal not otherwise provided for. Thus if there was a hand, lantern or other signal for a train to move forward, this would be the response.

An interesting change over the years is indicated by the use of one short (o) whistle signal. In 1898 it meant "apply brakes -- stop". In 1903 and 1907 it indicated, "Stop. Apply brakes." Nowadays a single short (o) whistle is used to indicate that the locomotive has stopped moving.

Another interesting change is that in 1903 and 1907 a whistle signal of two long and two short (-- -- o o) was to be given approaching a public crossing at grade. Later this was to become the familiar two long, one short, and one long (-- -- o --). I recall hearing once that this change was to ensure the whistle was being sounded at the grade crossing.

Brian Norden