im wondering about locomotive horns and bells for diesels(electrical klaxon horns and electrically-powered bells in current and historical use)…
can someone tell me about the harmonic notes (what key, and if more than one horn was used, what part of the piano keyboard might be the source?
bells
electrically-powered bells seemed to have more than one speed at which the bell sounded… i can tell 2 speeds which i can hear differently… one is a slower speed (almost 1 tone per second); the other is a faster rate, which sounded approximately 2-3 tones per second…
bells and whistles: when were these klaxon alarms developed? were the bell models developed for different speeds or different conditions? was a specification for the distance at which the alarms could be heard, under optimal comditionss? i read that a train’s klaxon could heard 3-4 miles distant, at night across a desert, under optimal conditions for wind speed and humidity…
Not sure if I have seen klaxons in American practice (these are a patented design that uses a toothed wheel to vibrate the diaphragm, rather than compressed air). Because American practice uses air brakes, it’s a simple thing to have high-pressure air at hand for horns…
If by ‘electrically powered bells’ you mean the synthesized versions on some modern locomotives, there’s no particular reason they can’t have multiple speeds. Older diesels have a physical bell, and I am not sure whether it’s electrically or pneumatically dinged – but I agree, I think at least some engines have a fast and slow speed. I’d think Don Oltmann would be in a position to know this.
With regard to tones: I know the Canadians mandate a minor D chord but I don’t think there is any fixed requirement in the USA. Base chord was determined by the particular tuned horn bells that were put on, and of course there would be some note variance depending on Doppler effect when moving.
All the ‘loudness’ specifications I have seen are in terms of spl, not in terms of audibility at a particular remote distance. It is not unusual to find modern horns that have variable amplitude.
The distance a horn can be heard under reasonable conditions is MUCH more than 3-4 miles, if you’re listening for it. I once had the fun of hearing an EL passenger train come ALL the way down the Pascack Valley line to Oradell one crisp,clear night; even today I often hear trains on the NS main line south of me, which at its closest point is over 10 miles away. Granted, it’s not loud, but clearly recognizable (even to the point where, if you know the base chord, you can estimate the speed from the pitch shift).
Bells are a very short-distance thing, intended more for foot than vehicular traffic. At least one railroad in Mississippi rigged their bells to ring continuously whenever the locomotives were in motion. This was supposedly done after a court case (det
Don’t know about C&NW’s gongs, but any locomotive bell I’ve encountered is pneumatically actuated. I have run into locomotives with an electrical switch instead of a valve, but the switch just activates a solenoid valve.
The ring rate varies just based on the age and physical variables of the bell, especially on vintage locomotives.
CNW gongs were electrically operated, and trainlined via a pin in the standard M.U. cable. Used to be murder when these units were m.u.ed with units from other railroads (Chessie’s the one I remember)…turning on the bell would cause the other units to do strange things like drop their load.
There had to be different speeds of pneumatic bell ringing available. The GTW’s 1960-built SW1200s were among those that had a fast ringing rate (all of them…and they were nearly new when I first heard them). Most other units I was familiar with had the typical rate of approximately once per second.