Some like it hot

July 28, 2005 12:33 PM

Why are New York subway platforms so hot?

I know it's summer, but yikes. NYC subway platforms are at least 10 degrees hotter than above ground. I've been on many subways in many cities, and never have I experienced the furnance-like tempertatures found in New York. Can anyone point to a reason it's so hot down there?

posted by nyterrant to travel & transportation (22 comments total)

I had some subway geek try to convince me once that it was all due to heat released by the brakes on the subway cars, but that's pretty much rubbish. There are three main causes of the heat:

1. Exhaust from the air conditioning units on cars.
2. Steam pipes that use the same tunnels or space.
3. Heat radiated downward from the surface streets that have absorbed it.
posted by Mo Nickels at 12:36 PM on July 28, 2005

...air conditioning units on subway cars...
posted by Mo Nickels at 12:37 PM on July 28, 2005

I've noticed some of the really deeper lines are noticably cooler... that makes it seem more like a surface street issue.
posted by reverendX at 12:44 PM on July 28, 2005

Steam pipes are operating during the summer? What for?

I think sewage lines giving off heat may also add to the misery, but that's just speculation.
posted by Pollomacho at 12:47 PM on July 28, 2005

Why steam in the summer? Cooling! Steam air conditioning in NY.
posted by true at 1:00 PM on July 28, 2005

I do believe it is the brakes, but I can't prove it. It is coming from the trains in any case. You'll notice that the more trains using a platform (and the more often the train comes), the hotter the platform. That is, at Union Square, the 4/5/6 platform is *much* hotter than the L, and at Lorimer-Metropolitan, the L is much hotter than the G.

Unlike others above, I've found deep lines hotter, with stations that have the vents to the street cooler.
posted by dame at 1:11 PM on July 28, 2005

That is, at Union Square, the 4/5/6 platform is *much* hotter than the L, and at Lorimer-Metropolitan, the L is much hotter than the G.

This doesn't prove anything, since the 4/5/6 platform is much closer to the street than the L, and so more susceptible to heat radiating from the street.
posted by Mo Nickels at 1:21 PM on July 28, 2005

This article may shed some light on it, if anyone can get it (bug me not isn't working). Another from the Washington Post about their metro, does indicate that train brakes add heat.

And Mo, actually Union Square is a bad comparison because the L has fans--I forgot. But my L stop is very close to the street & is very cool--much cooler than any express-local stop I've ever been at.
posted by dame at 1:24 PM on July 28, 2005

Not sure but I'd bet part of the problem is ventilation. All that air is just stuck down there and insulated by surrounding dirt etc. Nowhere for the heat to go.
posted by darksquirrel at 1:27 PM on July 28, 2005

Also, from the little bit of that Sun article that shows up on google, there seems to be something to do with circulation: so perhaps it is hot if it is close to the street but not vented and cooler if it is both close to the street and vented.

But now I'm way past speculation, so I'll shit up and see if someone can get into the Sun.
posted by dame at 1:28 PM on July 28, 2005

Hmm. A human body kicks out, what 100 watts? Call it 4 million journeys a day with an average, of, say, 20 minutes per journey? I make that 133 megawatts per day.

My math is probably completely wrong, but I bet that heat radiated from bodies is a significant factor. Anyone care to guess at how much heat is generated by braking?
posted by Leon at 1:46 PM on July 28, 2005

Although now I think about it, human-generated heat (and the extra heat caused be shifting it around with A/C) probably pales into insignificance when compared to sunlight heating the ground above.
posted by Leon at 2:19 PM on July 28, 2005

I've been on many subways in many cities, and never have I experienced the furnance-like tempertatures found in New York.

You've not been to London? It's insanely warmer in the Tube than above ground 99% of the time.
posted by wackybrit at 2:35 PM on July 28, 2005

I used to live in London. But the heat in the Tube is nothing compared to what you have to face in New York.
posted by nyterrant at 3:15 PM on July 28, 2005

Try the 9th street PATH station some time if you want to REALLY bake. It's unquestionably the hottest station I've been in anywhere in NYC.

I shudder to recall how many summers I spent commuting via that station. Gah.
posted by bcwinters at 3:47 PM on July 28, 2005

And Mo, actually Union Square is a bad comparison because the L has fans

But I swear the L is still roasting. I was at 6th Ave the other day and it was the hottest platform I've ever experienced. frankly, I'd think the 4/5/6 would be waay cooler since their ceilings are usually higher and the heat has more room to rise away from the platform. I think we need to follow North Korea's example of air conditioned subways.
posted by scazza at 4:25 PM on July 28, 2005

Related: Why is it so hot on the [London] Underground?
posted by blag at 4:29 PM on July 28, 2005

a) NYC subways use partially-regenerative brakes. Everything that's not regenerated becomes heat. That's a LOT of kinetic energy.

b) The motors produce a considerable amount of heat, as do any/all electric motors.

c) If deeper lines are really cooler, the 168th st 1/9 stop - 150-180 ft underground by my estimation - really didn't get the memo. It's frequently 100+ degrees down there in summertime.
posted by ikkyu2 at 5:53 PM on July 28, 2005

Wait, blag's link says the trains in London aren't air-conditioned. Is that true? Because in New York, it's just the platforms. It also says that only new systems have AC in the trains, and I know that's a lie--we have it.

Anyway, scazza, the Union Square L is nothing for the 4/5/6, I promise. In summer, if I'm going downtown, I'll take the N/R just to avoid that platform of doom.
posted by dame at 6:15 PM on July 28, 2005

Yup, no AC on the tube. There are plans to install AC units on certain lines I believe, but nothing soon.
posted by fvw at 7:19 PM on July 28, 2005

And here I thought it's because the deeper you go under New York, the closer to hell you get...
posted by five fresh fish at 7:23 PM on July 28, 2005

I wish the MTA would search a few less bags and divert the money to investing in big, powerful, "blowy" portable A/C units like they have in Newark Penn Station. Would make waiting for the subway oh so much more comfortable.
posted by GreenTentacle at 9:27 PM on July 28, 2005