Freight train whistles: legally required, blown for fun, or both?

http://en.wikipedia.org/wiki/Train_horn#United_States.

What is the pattern of the horn sounds? If it is two long blasts, one short blast, followed by a long blast, it's the sound they must make when they approach a crossing (in Montana, it's legally required for ALL crossings, although the rule is different in other states). If it's a quick succession of blasts, it usually means there are animals near the line that they're trying to scare away, which I hear quite often in my rural area. Union Pacific has a list of the different kinds of sounds and what they mean http://www.up.com/aboutup/funstuff/horn_signals/.

Fun fact: the spots for sounding the horn are marked with http://en.wikipedia.org/wiki/Whistle_post#United_States.

Hey, something I know about! (I design and test Railroad Signaling Systems for a living, and deal with crossings on occasion.) https://ask.metafilter.com/245811/Freight-train-whistles-legally-required-blown-for-fun-or-both#3569384 has the relevant link. Trains are required to sound the horn when approaching any public crossing, and continue sounding it until they are occupying the crossing. There are other reasons a train might be required to sound the horn, but they’re few and far between in comparison to crossings. If you live near a crossing, that can get annoying, but it’s a safety issue. Sounding the horn significantly reduces the accident rate. In 1984, Florida happened to create the perfect trial when they allowed individual cities/counties to enact nighttime Whistle Bans, but only for the Florida East Coast railroad (which operated entirely in the state of Florida). http://www.fra.dot.gov/Elib/Document/1258 found that from 1984-1989, while the nighttime accident rate increased by 23% at crossings where trains sounded the horn, it nearly tripled at crossings that were subject to a Whistle Ban. Of note—in the majority of the accidents, the driver had driven into the opposing lane to get around the gates. Based on that study, in 1991 the federal government stepped in and required the FEC to ignore any local bans. As whistle bans were rescinded elsewhere, http://www.fra.dot.gov/Elib/Document/1331 showed that sounding the horn reduces the accident rate by at least 30 - 60%. After several years of negotiation, public comment, etc., the final train horn rule linked above was issued in 2004. It formalized the concept of a Quiet Zone, a stretch of track 1/2 mile or more in which trains are prohibited from sounding the horn on a regular basis . So how do you get a quiet zone in your neighborhood? http://www.fra.dot.gov/eLib/Details/L03055 is complex, but to establish a quiet zone, you basically have three options:Have only grandfathered crossings that were already part of a Whistle Ban on October 9, 1996 and December 18, 2003.Design every crossing in the quiet zone to have gates, and to prevent cars from driving around the gates (one way streets, center median, or 4-quadrant gates). This can get expensive, $100k+ per crossing, and the railroad isn’t going to spend money just to make the neighbors happier, so the cost will ultimately come out of your taxes (local/state/federal).Use a complicated formula (based on car/truck/bus counts, train counts, speeds, crossing design, additional safety features, etc.) to prove that the risk index for your Quiet Zone won’t be higher than the national average risk index at all non-quiet-zone crossings. This is where you’ll see things like wayside horns (horns mounted at the crossing), increased police enforcement, improving sight distance, etc, which are cheaper than a complete redesign, but still reduce your risk index. This is subject to annual FRA review, and both your risk factor and the national average may change with time, so a quiet zone that qualifies today may require additional improvements in the future.

As a freight conductor, I rode many miles on locomotives, and I never once saw an engineer sound the horn 'for fun.' If 12-year-olds were running the trains, it might be different. But do you sound your car horn for fun?

am I wrong and is the person running the train just being a jerk and trying to wake the countryside by blasting the horn for fun? Wince. No, it is not "for fun". Train engineers (such as my brother) have -- thanks to physics -- amazingly little ability to avert accidents at grade crossings. Hitting a vehicle, especially when causing injury or death, is http://www.claimsjournal.com/news/national/2011/10/18/193215.htm. There are engineers who never work again after hitting a car. This is a http://www.youtube.com/watch?v=57WQAbwfwl0. Ignoring the Clubbed to Death background music ... skip to 0:45 to see the beginning of sounding the horn, which is well before there is even a vehicle at the crossing. Then an SUV pulls up to the tracks, and stops front end over them, probably listening to music or otherwise not paying attention until too late. The conductor (note: not the engineer) taking the video from the front of the train jumps inside the cab for his own safety. The train is immediately braking, but has too much sheer mass to stop until the cab is about 1/2 mile or more from the crossing. By the way, this is Mexico, so equipment is roughly equivalent to US/Canadian. If, after that, you're steeled for a fatal crash, there's http://www.youtube.com/watch?v=DOPtw5ZLX_c (at 0:12). I gather from news reports this was a car with 3-4 teenagers in it. It's chilling, and I wouldn't want to have to be the guy to get out of the train (2:20) to look for car ... or body ... parts. I know there have been a couple of operator-at-fault types of incidents lately, but from everything I know, professional railroaders blow the horn for your safety, even more so than theirs. FYI, I'm about three football-field lengths from two separate grade crossings. I probably hear the same thing 2-3 times on an average night.

But do you sound your car horn for fun? Only in tunnels.

There are freight train tracks near my home, but I only hear horn blasts in the middle of the night a couple times a month. We're exactly a mile from the train station, and the trains blow their horns all day and night. We really only notice them when there's low cloud cover, which reflects more sound our way.

It was law until 2005, when cities were allowed by the federal government to establish quiet zones. See, e.g. http://marfapublicradio.org/blog/soon-alpine-wont-hear-that-train-whistle-anymore/