Why are nyc subway trains so noisy?

[speedy1979]

I use the 2/5 train on the NYC subway 5 days a week and it's very noisy regardless of whether it's underground or above ground on the elevated lines.

I have noticed that Amtrak trains and Metro North/Long Island Railroad trains are much quieter than subway trains. Why is this? Is this due to wheel geometry or something else?

A technical explanation would be greatly appreciated!

[JManc]

every subway systems i've ever ridden on (quite a few) were pretty noisy.

[orulz]

I agree that the NYC subway is pretty loud. Seems a bit louder than most. I wonder why?

Nearly every line on the Tokyo subway is whisper quiet, except for the whirr of the traction motors (or whine if it's an AC trainset) and the woosh of wind. There's very little track noise even when going around some pretty astonishingly tight turns. Of course like any train it does clanks when it goes over a crossover.

[dchan]

I think the loudest noise on a NYC subway would come from the wheels rolling over a joint between two connecting rails. Since this happens quite frequently along the length of the train, I'd say that's where the majority of the noise comes from, especially underground where the noise echos.

The next loudest noises come from the air-conditioning system. I've been in cars without air-conditioning during the summer so I can get a seat (I don't really mind the heat that much), and they're significantly quieter.

The train motors are pretty loud also. And don't forget about the brakes as well.

The loudest NYC trains are the R42 trains, IMO. The E trains use them now, and they're noisy - they clank as they bang into each other, and their brakes are easily the loudest and most annoying brakes I've heard. The older R32 trains were so much quieter - I wonder why?

The trains are also not designed to be comfortable, long-distance commuting trains - that means much less insulation against noise from the inside of the cars.

[Rail Claimore]

Are there many places on the system where salt can get on the rails? If so, that's your answer. It's why Chicago's Red and Blue lines are so noisy: salt that is kicked up from the expressways into the medians rusts the wheels on the trains over time.

[dchan]

^ So THAT'S the reason why?

I thought NYC trains were pretty noisy, but then I went to Chicago - it was no comparison. I could have listened to music on my CD player on virtually any train in NYC back in high school; underground in Chicago around the Loop, that loud, jarring clanking noise completely overwhelmed even the highest volume setting on my CD player.

[Abner]

Yeah, Chicago is the loudest system I've been on by far, and I remember seeing noise studies that proved it (among the cities in the study anyway). I hadn't heard that it was because of salt corroding the wheels. I think it might also have something to do with the doors, because sometimes I'm on a car whose doors don't quite close properly and the sound is incomparably worse. It's always pretty loud though. It's even worse underneath the tracks where they're on steel supports.

[aaron38]

Maybe it's because I'm used to Chicago levels then, but I didn't find the NYC subways to be noisy at all.

[Mr Downtown]

At least Chicago now has sealed windows. Screeching around the State/Division curve in a 6000-series car with the windows open was a visceral experience.

[Attrill]

The two biggest factors are the age of the rolling stock and the conditions of the tracks.

There are a number of reasons that old rolling stock is noisier. Normal wear and tear leads to lose joints and fittings that rub and make noise. Newer cars use lighter materials, and a combination of CAD and computerized fabrication allow cars to be built to tighter tolerances. Older cars are also a lot heavier which makes them louder. I live close to the El and the cars are definitely louder at rush hour when their weight is increased by the passengers.

[big T]

This is the first I've heard of wheel corrosion being the cause for excessive subway noise. At least in my experience, this may not be the only factor though -- the Montreal metro uses rubber tires and I find it quite a bit louder than the NYC subway. Actually my gf and I were down in NYC this past weekend and she too noted how easy it was to have a conversation (that was on a 1 train in manhattan). In montreal's case, it's more of a loud, muffled hum. I'm guessing it's the ventilation system since it's about as loud regardless of whether the train is stopped or moving.

Oh and I can attest to Chicago's system being one of the loudest. I remember my friend shouting something at me while a train was coming in somewhere on the State St subway and I couldn't make out anything. That was absolutely amazing.

[CGII]

Are you talking about noise as experienced from within the car or from outside? Because from outside an Amtrak train sounds about as loud as any subway.

The new R160 cars that are gradually replacing older cars have improved insulation and seals and they are significantly quieter than the older cars.

Also I have to say what's already been mentioned; Chicago's trains are effin' loud.

[vid]

I live near a rail yard and I can attest to the fact that trains are louder in winter, especially when breaking. All night long you hear a high pitched whine of rusty metal scraping against rusty metal.

It's better after the LORAMs go through in April.

[dchan]

Originally Posted by CGII

Are you talking about noise as experienced from within the car or from outside? Because from outside an Amtrak train sounds about as loud as any subway.

The new R160 cars that are gradually replacing older cars have improved insulation and seals and they are significantly quieter than the older cars.

Also I have to say what's already been mentioned; Chicago's trains are effin' loud.

I guess that supports my hypothesis.

The loudest noises come from the train wheels hitting the gaps between consecutive tracts - since it happens a lot over the length of the train, and because it's happens in an enclosed tunnel underground, this noise multiplies and intensifies. My guess is that the air-conditioning in Amtrak and commuter trains are also significantly quieter than the AC systems in older subway cars.

And last, but not least, is the amount of sound insulation and window/door seals used in the different train cars. Older subway cars don't use a lot, while Amtrak/commuter trains have to use a lot.

[dchan]

Originally Posted by Attrill

The two biggest factors are the age of the rolling stock and the conditions of the tracks.

There are a number of reasons that old rolling stock is noisier. Normal wear and tear leads to lose joints and fittings that rub and make noise. Newer cars use lighter materials, and a combination of CAD and computerized fabrication allow cars to be built to tighter tolerances. Older cars are also a lot heavier which makes them louder. I live close to the El and the cars are definitely louder at rush hour when their weight is increased by the passengers.

Good point - weight is definitely a pretty big part of it. Combine that with worn down parts on trains that have been used for decades, and you're going to get a lot of noise.

I wouldn't say they're the biggest factors, though (all trains roll over track gaps, regardless of their age).

[Dac150]

It doesn't bother me much, but when friends of mine visit and I take them down into the subway they never fail to comment about the noise, among other things. The newer cars, espcially on the E line don't seem to be as noisy. I guess it just comes with age.

[tdawg]

I actually don't mind the noise. Plus, you can tell when a train is pulling in, even from the street, so you can tell if you need to book it or not.

[ChicagoChicago]

One of the things that makes Chicago’s system so loud is that it’s elevated. The orange and blue line are nowhere near as loud as the brown line and red line elevated tracks. I would say that the red line subway is comparable to or slightly louder than the tube after visiting in September.

In Chicago, the age of the cars has a huge effect as well. On the elevated platforms, because the red line cars are typically older, they are much louder than their brown/purple line counterparts.

[theWatusi]

Most commuter railroads - Amtrak included - use continuously welded rail (CWR)--Extremely long pieces of rail are used and the joints in the rail are welded so that there is no break in the rail. This allows for faster and quieter rides.

I'm guessing the NY Subway and other subways have jointed or "stick rail" were 39 foot pieces are simply bolted together.

More info: http://en.wikipedia.org/wiki/Rail_tracks



welding rail (in my town ):

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[Smiley Person]

Originally Posted by tdawg

Plus, you can tell when a train is pulling in, even from the street, so you can tell if you need to book it or not.

That is actually a very useful feature especially since rush hour trains around here are usually a couple minutes off schedule. I find it hilarious that in a strange adaptation of ancient hunter-gatherer skills, I can spot buses ten blocks away, estimate how long until the next bus shows up by the number of people waiting at the stop, etc.