When a train approaches, why does the engineer always blow his horn in a particular way, with two long blasts, a short, then a final long?

Yo, M(atthew) Alice:

No Malice intended, but I bet you only answer the easy questions or the ones you can readily access in that big book of dopey questions you keep under your desk. Anyway, here's a real challenge. When a train approaches a crossing, the engineer always blows his horn in a particular way, with two long blasts, a short, then a final long. The melody varies -- sometimes it's very curt, sometimes sad; however, the pattern is always the same. If it were Morse code, it would be a Q. Is there any sense to this, or is it just a simple evolvement, like us, up from the primordial ooze?

-- Bill Hickey, Señor Diego

You must be referring to the cornerstone of all Alice wisdom, The Oxford Book of Dopey Questions. Actually, Pa Alice appropriated that years ago to use to press his ties. It's been a decade since he's gone any farther from the TV than the refrigerator or the can, so we're not sure why he's worried about neckwear. He does put on a clean undershirt for the Miss Universe contest, but that's about it. So lacking my favorite tome, we'll have to call the San Diego Railroad Museum library in downtown's Santa Fe station for an answer. Right you are, Bill, the standard train signal given at a crossing is two longs, a short, and a long. It goes back to the days when there was no other quick form of communication between engineer and crew or between engineer and rail yard workers. There was a time when the motoring public knew long-long-short-long was a warning to stop for an approaching train. Today we take it as a challenge to step on the gas and beat the crossing gate. It's not Morse code, just train talk.

There's a whole dictionary of horn signals. Three short means the train's about to back up; two short means the train's about to move forward. And of course the classic old-movie sound -- one long blast (seeming to rise and fall in pitch because of the Doppler effect) as a train hurtles through the night. This means an express train is passing a railroad station without stopping. As for the rail crossing signal sounding "curt" or "sad" or whatever, "short" and "long" are relative terms. Some cities require the engineer to make the signal as brief as possible so the neighbors' tranquility isn't disturbed. In more rural areas, the engineer can extend the longs and shorts and put some muscle in it.

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