What does a “W” in an oval mean to an engineer? It is found as a sign posted along the tracks. Does it mark the rail yard limit, perhaps? I’m not even sure where it is found along the tracks, but I do know it is a sign used in railroading.
“Whistle,” that is sound your whistle at this point.
that whistle signal would be at places like approaching an ungated/unlit crossing to alert crossing traffic.
It’s a whistle indication. Usually placed 1500 feet before the level crossing. When the train reaches the post with the whistle mark, the operator sounds the whistle–two longs, a short, and a long. The last long should last long enough to sound as the train crosses the level crossing.
Which gives you, if you’re sitting at such a crossing, the classic illustration of the Doppler effect:
BEEEEEEEEEP BEEEEEEEEEEP BEEP BEEEEOOOOOOOOOOP
Which gives me, sitting at my computer, the first ever (for me) doppler effect…in written form.
The whistle sign can also be an X instead of a W. Union Pacific uses the X on their former Missouri Pacific trackage, while Kansas City Southern uses W in the same area.
You know it is remarkably hard to find a reference for this on the Net. You would think with all those rail fans out there…