Train Horns—Sound volume and range?

I've always known that train horns are by far the loudest horns I'll ever hear in everyday life, and this was verified by:

At Fairway Golf Center, about 1 mile from Edison station (NJ), the faint sound of an Arrow III horn was still audible at the Par 3 course. This was followed by numerous clacks of the axles pounding a switch or a brace on the track. In addition, the horn was not too faint. Also, a Regional's horn was heard shortly afterwards the same night.

So what is the volume (dB) that these horns are set? (what is the regulation?) I also remember reading that it has to do with the ambient conditions (temperature, geography, etc) that determine how far a train's horn actually goes. (Another instance is the freighter that is still heard in my classroom at school > 1 mile away) There is a grade crossing at Inman Avenue (Edison NJ); if anyone can look this up, feel free to post info.

I don't have the answers, but they are pretty impressive horns. Outside, late at night I can just hear them from almost 5 miles away (the nearest tracks to my house).

I live about 6-1/2 miles to the south, and I can faintly hear the horns blowing for the grade crossings in Hackettstown. That's either in the early morning or at night when it is very quiet here in Lebanon Township. Just an occasional dog bark, horse whinny, cow moo, etc. and NJT horns! (well, once in a while a car goes by, too) <g>

I live in Berkeley Heights about a mile from the tracks. I hear arrow horns decently well and the K5LA horns very well usually.

But, sometimes when things are just right, I'm pretty sure I can hear the train horns blowing on the RVL at Fanwood. May be hard to believe, but its true.

If you haven't noticed, the AEM7s and NJT diesels are REALLY loud.

The ALPs can get pretty loud but a lot seem to have been toned down.

The Comet IIIs and IVs can get really loud but have quite a bit more flexibility. Plus, 3 of the 5 bells on the C3s and 4s are actually facing towards the rear. And they still are pretty damned loud. The three facing towards the rear are the lowest sounding ones and are in the middle leaving the two outer ones facing forward and these are the highest pitched ones.

The Comet V horns can range from pathetic to REALLY loud. There aren't many really loud ones though. The loudest cab is I believe 6004 (which incidentally also has the number on the cab door higher than usual.)

Years back, I believe there was some sort of petition in our apt. complex to forbid trains from blowing their horns past our buildings, esp because of their loudness. Don't know if it was successful, but nowadays, you can hear lots of horn blowing at the new bridge they're building just west of Metropark. In normal conditions, trains do not blow their horns at all. (the area between Metropark and Metuchen [where our apt. is located] doesn't really require horns anyway)

It was said that the late-nighters into or from Penn Sta. kept the residents up all night. Interestingly, my mom also commented about the loudness!

The sound level requirements from the CFR is:

"A minimum of 96 decibles measured at 4 feet above the railhead at the center of the track gauge 400 feet in advance of the locomotive."

This is an area of particular interest to me.

I live in Crystal Springs, MS -- and in the distance from the city, most older diesels are audible. Heheheh -- there's a train running through town even as I post this: I just heard its signal for the grade crossings.

There's something I've noticed with one of the black CN diesels that has an all-but-silent horn. Unfortunately, every time I've seen it heading-up a train (and been first in line at the crossing), I haven't had anything to write with. If you happen to know which locomotive this is, please complain to CN about it, and let me know which loco it is so I can tell if it's a different loco.

The first time I saw it, I had been third in line at the crossing after the arms lowered -- which was *several* minutes before the train came through town, about 45 mph. Both my windows were down. It was a comfortably warm night with what seemed to be a dense fog beginning about 1000 feet down the tracks from the crossings; the fog obscured a cut of freight cars.

After a lengthy wait, the two cars at the front of the line drove around the crossing arms and I pulled forward to take up the space. After another few minutes, I turned off my engine and left my parking lights on. Most of the people behind me did the same. Some time later, the train seemed to just explode out of the darkness, and I kid you not, if the person in the cab of the lead locomotive had leaned out the window and blown a harmonica, I think I could have heard the tune of the harmonica above the sound of the horn.

Making things worse, the headlamps of the locomotive weren't effective beyond probably 300 feet under those conditions: that's about how far away the train was when I first saw the glow against the fog. Apparently, the fog bank had closed in while I waited.

The people who "ran the gates" probably thought the reason for the crossing arms being lowered was a signal malfunction, and they almost certainly never realized that they were minutes from being smashed by the oncoming train. We occasionally have such "malfunctions," which is probably part of the reason why CN has limits on how far ahead of the train the crossing arms must be activated and how quickly they must lower, etc. Anyway, I had started feeling like an idiot for sitting at the crossing and I was *tempted* to "run the gates," but I didn't.

Literally, there's no way that I could have worked my way past the gates in the roughly two-and-a-half seconds from the first glow of the lights on the track until the train crossed the street. I hope none of this comes across as melodramatic, but I don't think the people in front of me had any real appreciation for the danger.

We still don't have crossing arms at all the grade crossings in my state, and while I'd like to see *all* grade crossings either (1) eliminated altogether (replaced, where practical, by either an overpass or an underpass) or (2) protected by crossing arms, that probably isn't going to happen in the near future. Several of my relatives and friends/associates of my family and friends/associates have been killed at unprotected grade crossings.

I appreciate that there is a such thing as *too much* volume, so I'm sensitive to the idea of attenuating the blast of a train's horn in areas where additional loudness doesn't really serve a legitimate safety interest. I don't want there to be a competition to see how loud we can make a train's horn: that's asinine and counter to the safety interests of railworkers and others. On the other hand, I think we need to do all that we are able to make sure that the audio and visual warnings radiate sufficiently and with enough "authority of presence" to be heeded by people who simply didn't otherwise know the train was there.

I hope I've shown how absolutely essential an effective audio warning is: when people can't see the train, they usually don't believe that it is there -- and if their ears aren't sufficiently offended, they won't pay attention to the other indications, especially if they perceive it as an inconvenience.

So -- downtown or countryside, we *need* loud trains.

PS: don't forget to look for the "silent" CN locomotive!

Methinks my math was way off.

Here's how 300 feet looks at various speeds and times:

Seconds MPH
4.545 45.0 (it didn't take anywhere close to this long)
2.557 80.0 (i have great difficulty imagining a freight at this speed)

So, cutting the distance in half (which is very scary, if you think about the visibility of an oncoming locomotive's headlamps being only 150 feet), we get:

Seconds MPH
2.273 45.0 (this is about right)
2.500 40.9 (it seemed to be moving significantly faster than this)

Ah, anything's possible with a freight nowadays. Observe the great desert plains of Arizona and California, for example. Last summer, the action was quite boring, but I spotted many trains being 'stuck' miles apart on the same trackage (viewpoint from I-40). But 3 summers before that, we spotted a 100-car freighter just short of 75mph. (our cruise was set to 75, and we inched ahead of the train) While not quite 80, I think this is fast enough to serve this purpose.

Not to get off topic with horns but what about the engine itself i live about 3/4 mile away from the CR station in Lowell,Ma and at night I can hear the engine pull in with it's bell and engine nosie clearly audible from my back porch and there is alot of stuff the sound travels threw just to get to my house. Also i can hear the Guilford Engines down by the river on the straight away reving there engines during the night.

It's also not hard to catch a V16 diesel pounding away across far trackage. Not sure about the current NJT F40 and GP40 fleet, but the new PL42AC's are set for 88 dB when idle. According to TR00, the minimum horn regulation is 96 dB, so you would hear the horn before the engine.

Keep in mind, diesel motors are naturally louder than gasoline ones. [/list]

F40,

You forget one thing, the lower the pitch, the further it travels. This is one reason why the Penn Central had to remove the Hancock Air Whistles from the former NYNH&H locomotives, the db was high enough, but they didn't penetrate far enough ahead of the locomotives.

So theoretically and in practice, you will hear the rumble of a reving 16 cylinder EMD long before you will notice the horn (depending on surrounding structures)

Rich C.

I stand corrected.

But is there a limit in which that rule can be used? (i.e. conversational dB wouldn't carry farther than a train horn)

I live 12 miles away from Weedsport, NY and somtimes on a vary, vary cold winter night I can here the vary faint sound of the trains horns its rare thow. I can also here the Finger Lakes Railway horns as well but thats old news to me the track is about 3-4 1/2 miles from the house.

Train horn volume is very complicated. I have been involved in testing them. Trying to get a certain decible is correct but there is much more to it than that. In locomotive testing we have to record data from front, rear, side, and 45 degree angles at varying distances while the locomotive is in idle, throttle 8 load test and also moving at various speeds. We also have to be very careful that the horn (and engine noise) does not exceed a predetermined level inside the cab. I cannot recall the site (possibly FRA's) but you can get these minimum requirements on the net somewhere. Remember that these are only minimums. Certain railroads want them louder externally, quieter inside the cab, different tones, etc. Also, the maximum operating speed of the locomotive sets in a whole set of new parameters. Horn placement becomes a major issue. Moving a horn just a couple of inches can make a major difference both inside and outside the cab. As stated earlier and as we all know, Weather, wind, barometric pressue, all play major roles.

Air horns are require a tremendous amount of air (most have about a 3/4" to 1" line and then choked down inside the horn itself) . At 125 psi (normal pressure) the volume consumed is extremely high. Those truck drivers that put chooch horns wont admit it but they know good and well when they blow that horn, they loose a major amount of resevoir air pressure and in a matter of a couple of seconds will cause their emergency brakes to apply.

Increasing the supply pressure is not practical due to the designs of locomotive air systems and increases in volume consumed are nearing a level in which a measurable drop in air tank resevoir pressure is noticable in a single unit application. Air tanks are expensive and take up alot of real estate on a locomotive.

I predict in the next 5 to 10 years, the electric horn will likely be the end of air horns on new locomotives if the reliability can be proven better than the current air system. The cost savings would be dramatic and reliability increased. Air horns, valves, and piping are very expensive and high maintenance for railroads. Two wires and bolt on horn would work very nicely. When electro-pneutmatic brakes start becoming common along with cab electronics like on the newest EMD and GE units, it will only be a matter of time before the air horn goes way of the steam whistle. Within 20 years, new automobiles will likely receive a signal from major railroad crossings and/or locomotives and respond as necessary and perhaps flash a message to the driver. The technology exists today for this in the newest locomotives and automobiles.