The Underground is heating up
June 19, 2017 9:13 AM   Subscribe

Over the years, the heat from the trains soaked into the clay to the point where it can no longer absorb any more heat. Tunnels that were a mere 14 degrees Celsius in the 1900s can now have air temperatures as high as 30 degrees Celsius on parts of the tube network.
As it's a nice, balmy 31 degrees in London at the moment, have a refreshing article about cooling off the Underground.
posted by MartinWisse (41 comments total) 30 users marked this as a favorite
Dude, It's above 80 (fahrenheit) in the Bronx today, and I just got back from my buildings laundry room which the dryers turned into a fucking sauna. I dunno whether to be pissed that you mentioned heat or grateful that you mention cooling.
posted by jonmc at 10:01 AM on June 19 [3 favorites]

A conversion table for Yankee readers:

10 °C = 50.0 °F
20 °C = 68.0 °F
21 °C = 69.8 °F room temp
30 °C = 86.0 °F
37 °C = 98.6 °F average body temp
40 °C = 104.0 °F
posted by MrJM at 10:03 AM on June 19 [8 favorites]

Please read this Twitter thread if you're not from the UK and don't understand our "whining" about high (to us) temperatures.
posted by thetarium at 10:07 AM on June 19 [12 favorites]

Clearly they haven't played enough Oxygen Not Included.
posted by runcibleshaw at 10:10 AM on June 19

Yesterday we had 85 °F with around 70% humidity and it was horrible. Anybody calling someone else a whiner because of heat can cram it. Although I do retain the right to chuckle at the South American premier league players wearing parkas on the bench when everyone in the stands are in short sleeves.
posted by cmfletcher at 10:18 AM on June 19

That's an excellent article all about ventilating underground railways, and how they accumulate heat. It'd be a shame to miss it because everyone wants to be snide to everyone on the other side of the Atlantic from them.
posted by ambrosen at 10:21 AM on June 19 [13 favorites]

Interesting that they are experimenting with using the trapped heat for winter heating, I will be following that up, its something I have previously wondered about since this has been a problem they have been trying to address for a while. I should be able to make a good student project out of some of this.
posted by biffa at 10:22 AM on June 19 [4 favorites]

Currently speaking as someone in an empty railway carriage that just came out of a cool (and very old) tunnel. It's empty because it is 30°C here, and the air conditioning's not working on this coach. I've stayed in it because it's a declassified first class one, so I'm boiling in a large leather armchair right now.
posted by ambrosen at 10:23 AM on June 19 [4 favorites]

> my buildings laundry room which the dryers turned into a fucking sauna.

Checked whether the dryer exhaust vents, if they exist at all, are plugged with lint that got by the filters?
Check the filters -- and beyond. You know nobody else is bothering to maintain this stuff.

There's no reason that hot humid air should accumulate inside the laundry room.
If it's happening, you've got a fire hazard accumulating.
posted by hank at 10:29 AM on June 19 [8 favorites]

Please read this Twitter thread if you're not from the UK and don't understand our "whining" about high (to us) temperatures.

Thanks for that. Here in Northeastern Mexico we get mostly 100ish degree (F) weather (anything from 35 to 42 sometimes even 45C) all summer. And summer basically starts in May and ends in September, so we are used to suffering from the heat for days on end. I could never understand how heatwaves of 30C end with so much caos in Europe. Now I can understand at least a bit of it.
posted by CrazyLemonade at 10:39 AM on June 19 [2 favorites]

Interesting! I have twice had the misfortune to be in the UK during heat waves, and taking the Tube was always an...experience. Did notice some cooled stations along my route last visit, though (which was not during a heat wave).

Please read this Twitter thread if you're not from the UK and don't understand our "whining" about high (to us) temperatures.

The difficulty during the aforementioned heat waves was never really the heat (I'm from Southern CA, have lived in Chicago, am used to much hotter weather), but that there was nowhere to go to escape it. Indoors? No a/c* and the buildings, as mentioned in the Twitter thread, hold the heat. Tube? Yikes. Buses? Ditto. So definitely no snideness here.

*--I developed a new fondness for McDonald's, which a) has a/c and b) serves soda US-style, with lots of ice.
posted by thomas j wise at 10:41 AM on June 19 [6 favorites]

Pfft. A couple of window AC's in the cars and everyone will fine.
posted by Thorzdad at 10:42 AM on June 19

This is crazy fascinating to me. It had never occurred to me before reading this that you’d have to deal with the effects of tunnels as heat sinks. The solutions they’re trying are just as interesting.

Please read this Twitter thread if you're not from the UK and don't understand our "whining" about high (to us) temperature

As a Southerner now in the Pacific Northwest, I can attest to her take on the heat. I grew up in Florida, where you have precisely two seasons: Summer, and Not-Summer. The heat’s just baked in to the way of life down there, as it were, and you live with 85-95°F (29-35°C) from around March to October. That was my life for nearly 30 years.

Cue today where I’ve been living in Seattle for 16 years, the local temperature range strongly mitigated by the 55° waters of Puget Sound lapping at the city’s edge. You adapt to your conditions, and I now find 75° to be genuinely hot. There’s a part (a very large part, too) of me that practically screams with laughter whenever I start to complain of Seattle’s summer “heat,” but what can you do but shrug? Your body adapts to the local temperatures. People from hot climes laughing at your misery doesn’t make it any less real, it just makes them assholes.

By the same token, I may smile when I see visitors to the area bundled up when I’m in a tee-shirt and thinking just how lovely and warm it is, but I can’t mock them for it. I may be happy throwing on a couple of tee-shirts and a pair of long shorts for a bike ride when it’s 40°F outside, but that’s only because I’m (now) used to it. If you’re from a warm climate and visit places significantly cooler, it can feel damn cold, never mind the perceptions of the locals.
posted by los pantalones del muerte at 10:50 AM on June 19 [7 favorites]

On some lines, there really isn't space to throw ACs at the trains. And even then, what do you do with the heat? Because it's not really going to solve the problem long term to just dump it back into the underground. Half the stations are already sweltering in summer.

I grew up in Hong Kong, with mid-to-high 30s (celsius) and 90+% humidity being common. I suffered more in the heat yesterday here in the UK than I did in 12 years in HK. There is no air conditioning here. Anywhere. If it is 30 outside, it is 30 (or more!) inside. Buildings are constructed to avoid draughts, not encourage them, so it doesn't cool down anything like as much as you'd expect at night. It's the utter lack of escape that makes it horrible (in a similar way to how the few weeks of cold - 12 degrees or so - each year in HK was much worse than winters in Europe, though you could always layer up sweaters. Once you're naked, you can't get cooler by taking more clothes off.)
posted by Dysk at 10:54 AM on June 19 [3 favorites]

While that heavy thick clay is lovely to tunnel through, it is also a heat insulator.
Ya, no. Clay is not an insulator in any meaningful sense. It's just that like a pot of water boiling on a stove a material will heat up if you apply energy faster than it gets carried away. The deep earth at the point had a steady state temperature of 14C. The introduction of any heat source was going to heat things up proportionally accounting for the difference in ΔT has on cooling.
posted by Mitheral at 11:03 AM on June 19 [6 favorites]

Case in point for a place with the opposite problem from London's stay-warm design: I went to school in Houston. In at least one of the older buildings there, the cooling system did not come with an off switch (I presume it could be shut down for maintenance, etc., but it was not a simple process). Instead, if it actually got cold enough that this was a problem, they ran the heater *on top of* the cooling, relying on the cheap energy you could get in Houston.

All of the above was handed down to us and may have been a campus legend, but while I was there, we had a cold snap/ice storm hit, and the heater broke, causing us to have classes in a building where the cooling was running full blast despite it being literally freezing outside.

(I'm not saying A/C above because it didn't seem like it was technically A/C, but rather a system that involved running extremely cold water through pipes in every room, with fans blowing cooled air around.)
posted by Four Ds at 11:15 AM on June 19 [2 favorites]

Mitheral, they are probably trying to describe the heat storage and transfer of the London clay, which is high and low respectively -- high heat capacity probably mostly because it holds a lot of water, but relatively low transfer because (informed guess) dense clay doesn't allow the water to move much so there's scant convective loss.
posted by clew at 11:19 AM on June 19 [4 favorites]

Yeah I worked in an office building like that. Cooling always ran, if you wanted it to not be so cold, you'd run the heater. I had a (corner) office with it's own heater controls so I was one of the few in the building who was not cold all the time

Facebook recently reminded me of this by showing me a picture of a coworker I took, 4 years ago yesterday, of a coworker at his desk in a parka and ski cap.

(I live in Austin, it is typically 90-100F during the day here this time of year)
posted by RustyBrooks at 11:20 AM on June 19

Sure it may be 10000° here, but it's a dry heat.
posted by blue_beetle at 11:24 AM on June 19 [2 favorites]

so it doesn't cool down anything like as much as you'd expect at night

I remember reading something a couple of years ago, after a heatwave in EU/UK that came with serious casualties, that typical residential building construction also means a sort of inversion (except I think it was a different term, and I'm drawing a complete blank) effect inside after the sun goes down, so that living areas are effectively being residually heated in the evenings. That's a good thing in a cold winter, even in a cool summer, but it can kill on those 10-40 days a year when it's legitimately dangerously hot outside. (And the cost of comprehensive cooling solutions, that you only need 10-40 days a year? Impractical, space-consuming, and often reduce the efficiency of heating solutions needed many many more days a year.)

So it's "not that hot" out but the air is like a hot wet sheet, you spend all day battling it, and then you can't cook and you can't sleep or even rest and your core temperature never gets to come all the way down to normal, over multiple days. And, as someone else said, in a generally cold climate people get sun-drunk and deliberately get overheated, or have no idea how to walk around outdoors in hot weather.

In nearly-year-round hot climates, you see that accounted for in thick and/or air-gapped walls, internal courtyards/atria that can be used to draw air out of the inside of the building, small outward-facing windows, high ceilings, lots of shaded outdoor space. Those buildings suck in the cold - those walls basically turn into refrigeration units - but those cold snaps are brief and generally not cold enough to kill the way the heat will.

In the US, because of the prevailing aesthetic, a lot of us live in residential construction that does not suit the local weather most of the time (rather than the occasional mismatch of European construction), and that's why climate control is so pervasive here. We're not even trying.

It is ridiculous that Los Angeles has this many ranch-style houses and thin-walled multi-family buildings, with thin veneer stucco rather than proper thick walls, that I can really only keep it about 15 degrees cooler in than out - and that same inversion process means that at some point in the evening the outside temp will drop below the inside for a while - at least our nights usually cool off at all. You can tell there's jack shit for insulation in the walls because I can hear a spider fart in the back bathroom from the opposite corner of the house. And it seems like almost all residential AC is compressor-driven rather than swamp cooling - because occasionally the humidity goes over 25% here and THEN WHAT HUH?? But more appropriate styles of construction - Central/South American-style or Mediterranean - doesn't look "right", cough cough. So just build an attractive oven and plug in a giant HVAC system that doesn't work all that great on dry days, so install one twice as big as you ought to need.

Large commercial buildings, if I'm understanding correctly, really are effectively air conditioned full-time because a) air needs to move around and be circulated and refreshed and filtered b) and this needs to happen more or less equally across the entire building* c) most of these buildings are basically greenhouses and get surprisingly hot if not cooled, even in winter d) except then people get cold on a localized basis and so heating may be run on a completely separate system simultaneous to the ventilation system.

*I lived in a 12-story dorm in college that had such a stupid ventilation system that every room door had a 2ft square ventilation grate in it, meaning you had zero privacy and people would get written up for noise violations for whispered conversations or sleep-talking or having a TV/radio on, and none of the windows could be opened because the rooms on the other side of the floor would have all the loose items sucked up against their door grates until it got blocked and threatened to create a vacuum and/or suck their window out of its housing. This stuff is weird and complicated.
posted by Lyn Never at 12:08 PM on June 19 [10 favorites]

So, when I was a kid in west Texas we would visit Carlsbad Caverns in the summer. It might be 105° outside but it was always cool (maybe 55°) in the cave. The rangers said the cave temperature was roughly the average of the annual outside temperatures.

When it gets hot in the cave, it is a worrisome development.
posted by Bee'sWing at 12:16 PM on June 19

We're not even trying

To be fair, a whole lot of the continental US has four highly contrasting seasons. There's really no such thing as "building to suit the weather" in, say, the midwest, where it's absolutely frigid in the winter and pretty consistently in the 90s all summer. That is a huge swing in temperature. To me it seems normal because I grew up with it but every now and then I think of the first English colonists coming to the mid-Atlantic (I went to school in Maryland at the site of the third European settlement in the US) and what a jarring climate that must have been. As cold or colder than it gets at home for 4 months of the year, and then holllly shitballs we're all going to die it's 100 degrees and 100% humidity in this malarial fucking swamp!!!
posted by soren_lorensen at 12:46 PM on June 19 [6 favorites]

Ground-loop heat transfer into insulated buildings is a reasonable response to four drastic seasons. (And, to drag this back to the original post, some of the Tube fixes are trying to do that.)
posted by clew at 1:33 PM on June 19 [2 favorites]

I spent two weeks in London in August a few years ago, and everyone kept apologizing to me for the heat wave-- in reply to which I could only look baffled, because it was 75F with no humidity and cool enough for a cardigan at night. Coming home from that to DC summer armpit weather was horrible. I cannot imagine managing the kind of summer weather we normally get here with what I saw in London.
posted by nonasuch at 2:08 PM on June 19 [1 favorite]

I have oodles of sympathy for anyone dealing with high heat and humidity. I escaped Florida for good after 30-odd years of being absolutely fucking miserable for 6 months out of every year (and being only marginally unhappy for 4 of the other 6 months), so I feel their pain.

I have friends and family still living there and they're always asking me when I'm going to come back and visit. When I reply "Sure, how about in January?" they recoil in horror. I swear I must have been adopted.
posted by Greg_Ace at 5:49 PM on June 19 [2 favorites]

I was in London at the beginning of May when temperatures were basically between 10 and 15 C, and everywhere was generally pleasant except for the Tube, where I found the air to be stiflingly still. It wasn't even that hot but it just felt like there was no circulation whatsoever inside those carriages.

In nearly all ways I (sadly) find the Tube to be a superior passenger experience to the New York City subway, with the major exceptions of NYC's nighttime service and air conditioning on NYC subway cars.

I know not everyone is a fan of AC on cars, but I sweat incredibly easily at ludicrously low temperatures and with the slightest smidgen of humidity, so for me, it's a godsend.

I also know that the heat expelled by the cars heats up the platforms (to sometimes truly atrocious temperatures), but I'm willing to make that bargain since for almost all my subway trips I spend longer on the train than waiting on the platform.
posted by andrewesque at 5:50 PM on June 19 [1 favorite]

This was fascinating. Thanks, MartinWisse.
posted by Chrysostom at 7:25 PM on June 19

Ya, no. Clay is not an insulator in any meaningful sense.


It is an insulator in the sense that if the surrounding material had a higher thermal conductivity (e.g., granite), the temperature in the tunnel would be lower because the thermal energy from the trains would have diffused into the soil/rock farther and faster over the decades.
posted by Mapes at 10:06 PM on June 19

I always thought that the Central line was so hot because it went close to hell. And now I learn that it's actually the difference between sub-surface and true underground lines. Same thing, though, right?
posted by lollusc at 10:17 PM on June 19 [2 favorites]

soren_lorensen: "To be fair, a whole lot of the continental US has four highly contrasting seasons. There's really no such thing as "building to suit the weather" in, say, the midwest, where it's absolutely frigid in the winter and pretty consistently in the 90s all summer."

A well insulated (eg: double stud wall, R60 attic), four square, story and a half home home with wrap around porches and modest windows (mostly on the south but still on all expsoures) will perform well over much of the midwest. Make it rectangular in an east-west direction if you need more room. Have deciduous trees for shade on the south side and evergreens on the north for wind break. It will be fairly energy efficient with the ability to harvest sunshine in the winter and be well shaded with the capability for cross breezes in the summer.

Mapes: "It is an insulator in the sense that if the surrounding material had a higher thermal conductivity"

Sure, but compared to an actual insulator, say a chunk of EPS foam, it might as well be a copper bar.
posted by Mitheral at 10:20 PM on June 19 [3 favorites]

Excellent article; thank you for posting it.
posted by LobsterMitten at 10:23 PM on June 19 [1 favorite]

This has been a known issue for decades. I get that air conditioning isn't feasible in many cases, but why have ventilation systems remained so feeble? Why can't there be fans of sufficient strength? Even the newest rolling stock seems incapable of providing decent air motion inside crowded carriages.
posted by theory at 12:29 AM on June 20

Even the newest rolling stock seems incapable of providing decent air motion inside crowded carriages.

All modern rolling stock is a careful balancing act between power and space. Indeed space is even more of a premium on units designed for UK loading gauge because of the curvature needed on the body on the body side at ankle level which then reduces available floor (and below floor) space.

So not only do you have to work out how to fit decent heating and cooling into the train alongside all your wiring, displays and of course seats and standing space to meet the (generally high) expectations of capacity set by the likes of DfT and TfL.

What really, really matters these days though is power consumption. The rolling stock manufacturers are under massive pressure to deliver less power-hungry units and a lot of the contracts out there are increasingly making this a major decision-making factor. This isn't just a penny-pinching thing from the operators - it's because they are increasingly aware of the extra pressure that more train services and more trains are starting to put on the power network.

Case in point: One of the overlooked costs of HS2 is actually the power demands that an entire new railway is going to place on the grid. We were doing some back-of-the-envelope drunken sums in the pub the other day using the new Eurostars as a baseline for a guestimate on power consumption. They have an installed power of 16MW. Scale that up for the performance expected of HS2 trains (400m long, 360km an hour) and you're probably looking at a 21MW draw.

You don't need to be running that many units per day at those power levels to start hitting big numbers. Hinkley Point is being designed to deliver 3,200MW, for example - or roughly 7% of the UK's power needs. If our 21MW figure is right then 67 HS2 Phase 1 trains, associated infrastructure and the current expected timetable leads to HS2 on its own requiring a quarter of the output of something like Hinkley Point to run. Scale that up for HS2 Phase 2b (165 trains) and suddenly you're looking at half a Hinkley. And all that stuff applies in micro to new rolling stock fleets on existing lines as well.

Hence why power matters so much to the DfT and suchlike these days - because turning round to Parliament (or the public and saying) "oh, by the way, we need £18bn to build a new power station" is never a good way to endear your rail project to the British public. We're not quite at Apollo 13 levels of power conservation, but you'd think it sometimes when watching people design these things.

Indeed one of the major reasons that Bombardier just nabbed the South West Trains contract is because they've come up with some very clever bogie stuff to minimise power consumption. Stuff that Hitachi, Siemens et al. are now massively struggling to replicate. In a weird way, losing the Thameslink bid to Siemens was the best thing that ever happened up in Derby. It forced them to rethink their entire approach from the ground up in order to make sure they'd get Crossrail - and in doing so they've ended up creating (in the modified Aventra) something that's given them their first real technical edge in a long time.

Which is all probably the longest way to say "air con is power hungry and takes up lots of space" ever, but there we go!
posted by garius at 2:45 AM on June 20 [21 favorites]

I can't remember which tube station I was in over the weekend, but I did get several blasts of satisfyingly cool air as I walked onto a platform, which was very welcome.

Without wishing to yokelsplain garius, it's probably worth also adding that in terms of air conditioning London Underground tube trains, they are the smallest standard gauge trains in the world as far as loading gauge is concerned. So there's just not a lot of room even before you consider dispersing the heat.
posted by ambrosen at 5:11 AM on June 20

My approach to London so far this week has been: if I can't there on the Overground, it's not happening.

Blessed, blessed Overground.
posted by Sonny Jim at 5:39 AM on June 20 [1 favorite]

I (sadly) find the Tube to be a superior passenger experience to the New York City subway

Why "sadly"?

I definitely prefer New York's "cool on the train, hot on the platform" to the London experience. Being stuck in a hot, crowded Tube train that is held up by signal problems is *not* pleasant.

But the hear from the AC has to go somewhere, and on several occasions I have had to escape from the Times Square station after waiting too long for an A because it was unbearably hot.
posted by 43rdAnd9th at 8:48 AM on June 20

London has plenty of 'hot on the platform, hot on the train' experiences. I only go to London occasionally so can justify taxis fairly often when I am there. I have literally got to the top of the escalator at Waterloo on a hot day, felt the hot air rise out of the crowded hole in front of me and thought 'fuck it, its taxi time'.
posted by biffa at 3:38 PM on June 20

I (sadly) find the Tube to be a superior passenger experience to the New York City subway

Why "sadly"?

It's "sadly" as I live in New York and not in London, so I can't take advantage of what I feel is overall the better riding experience!
posted by andrewesque at 5:06 PM on June 20

You adapt to your conditions

I don't know. As a northwesterner (Montana and NoCal) who lived in Louisiana for three years, there were two things that I just could not get used to: a) the humidity, and b) the fact that it didn't cool down at night.
posted by CheeseDigestsAll at 5:16 PM on June 20 [3 favorites]

You adapt to your conditions

Or you massively adapt your conditions to you.
posted by ZeusHumms at 6:42 AM on June 22

Was definitely too cold in some of the sub-surface trains I was in over the weekend, and way too hot in the tube trains, but both issues made me think of this.
posted by ambrosen at 5:22 PM on July 11

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