Why The London Underground Makes Itself Hotter Every Year
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- Опубликовано: 8 авг 2022
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As someone who goes on the central line every day, I can confirm it is the closest thing I have to a sauna.
thanks to the Elizabeth Line, I legit never have to use it anymore
@@hx0d Can't wait for it to start through running :)
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The average price of a sauna in London is £20. Riding the central line off-peak will cost you roughly £1.60. See it, say it, sorted
Same with northern line. I always thought it was the people being packed that made things so hot, but even during off-peak hours, it's so fucking hot that I sweat no matter what I'm wearing
Worth noting that the new Elizabeth Line (which isn't a tube line by the way) is the coolest, as its newly bored (and also it has actual ventilation systems unlike the tube). So kids, if you're ever in London, avoid deep level tube in the middle of summer unless you want to be roasted like a chicken and use the Elizabeth Line.
I like the heat
Not to mention the trains are much bigger and are air conditioned. Its so nice using the Elizabeth Line during the summer, compared to the 'Central Line Sauna' as my friend likes to call it
Obviously the Elizabeth Line isn't a tube, it's a lineage of lizard people trying to dominate the world.
Fr though what is the Elizabeth line if not part of the tube? Technically part of the over ground?
And the Elizabeth Line is almost an express Central Line service on a portion of its route.
@@ye_mother so does satan
Extra points to the production team for using footage of a UK plug in a video about the UK! A nice little touch :) Also using Nando's as an example restaurant. You guys did your homework!!
👍
Calling it a subway every 5 seconds, I’d say otherwise.
@@masonwant Oh 😕 That's a very fair point!
Even to the extent that they understand the cause of overheating!
Unfortunately they used the subsurface trains to represent the tube trains.
I heard that one of the problems is they've broken the subtle way the deep tube tunnels were meant to vent, a methodology that required purposeful choices around the whole design, from the tunnels, to the station design: The trains are meant to act as air pumps. The tunnels are purposefully just big enough to fit the train so no air really circulates around and when a train travels through a tunnel, its effectively pushing out the air in front of it and pulling air in behind it. The idea was that this would aid ventilation in the way lots of fans might. pulling fresh air through vents and even down from the surface via the walkways, and push hot air out the same way. But from blocking vents, redesigning the flow of walkways, and even putting tons of signs and things in the path of this airflow causing turbulence, Lots of little things that have been added or modified over the years without considering this, has caused ventilation to get worse.
So basically this is a outdated and obsolete system if even some needed changes like new walkways and signs break it. And it has to be upgraded
I was kinda wondering if it weren't possible to just put in a system to push the air out of the tunnels. That should keep the temperature at something bearable at least until climate change has caught up with London.
Or just do what underground mines do and use multi stage fans to force air in. And if it’s too warm, water gets spared into the fan.
This is not true.
@@aridley579 that was helpful. Not. 🤦♂️
We love Central Line stander. I hate it with every fibre of my being so much that I choose to apply for jobs based on whether I would have to take the central line or not
The elizabeth Line has come to save the day
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fiber*
@@RockiestRock
"slander" was *actually* misspelled here, but you, pebble brain that you are, decided to "correct" the Queen's English word "fibre".
@@RockiestRock Nope. Fibre is correct. We are not Americans!
They really need to step up the regen braking, but it means redoing all the substations that feed the rails, and no-one wants to pay for it. The clay cooking also means there's a gap between the tunnel wall and the dirt, acting as more insulation.
Maybe they could ventilate the gap somewhere.
@@aayotechnology They can't ventilate it, they're too busy minding it.
Improving substations only improves deceleration and acceleration performance
I thought the 92 stock on the central line are already fitted with regenerative breaks
Regen braking was my first thought as well.
Maybe they can cool the trains down with cold water before entering the tunnels.
Make the last 500 meters before going underground a shower in ice cold water, that would lower the trains temperature before it goes underground, would it not ?
The Elizabeth Line is an oasis of cool in the midst of the inferno that rages on the other deep level lines in the summer months. The Central line slugs it out with the Northern for achieving some truly unbearable temperatures, especially if there is some service disruption that causes trains to stop in the tunnels. They are also probably the most overcrowded lines, because of their peripheral length, and the stations they serve. The new Elizabeth line will definitely relieve pressure on the Central Line, but won't make much impact on the Northern.
London was innovative in its creation of an underground transit system, but the technology and demand in the early 1900s were primitive compared to what would be built today, as Crossrail has shown. So we have paid a price by being early adopters. Still, something needs to be done. It will be interesting to see how the plans for AC on the older lines work out. There is very little room to play with on the trains, nor on the surface for new ventilation shafts and associated plant. So they're going to have to be ingenious to find a cost-effective solution.
They've managed to fit AC on the new rolling stock (whenever that's supposed to be introduced) and the regenerative breaking will help a good amount too. I read a while back that they've also got a series of rolling projects to help with ventilation along the line. They've been experimenting with different solutions in different stations. A big reason for the heat is the fact it's surrounded by clay, which is an excellent insulating material. It's also drying out given how long it's been there so less passive cooling from any moisture that would otherwise help whisk it away.
Thameslink kinda covers the Northern Line, so I think that’s good
The point is made, AC will only increase tunnels temperatures so it's not the answer!
Re the Elizabeth Line, give it time. I predict it will overheat
@@calvinbarrows3018 if you visit metro systems in countries where temperature control has been designed in, they do not overheat. So why would you predict that the Elizabeth Line will overheat?
physics teacher: *ignores friction*
underground engineers: he's a god damn genius
The heat is way more than just brakes, the motors also produce a lot but people are the major generator, there is a massive difference in temperature between the quietest hours and rush hour.
A person is a roughly 600 BTU/h space heater. Even if the trains were somehow completely non-heat-generating, the number of people in the Central Line at most hours would itself be a huge heat problem.
Yup humans produce around 100watts of heat on average if I'm not mistaken
@@hsy831 about 100 watts _at rest_. Active humans (such as those who just sprinted to catch their train), can produce 800+. Usual HVAC planning is based on 176 watts/person (well, 600 Btuh/person, so I'm rounding).
600 btu at rest?
Holy damn
That is 1/3rd of a space heater
@@tsotate Well a 2000 k calorie diet is equivalent to 98 watts *averaged* out, so I think you're numbers are a little high. But when active, I can certainly see the 176W number and higher (i.e., strenuous exercise).
I wish I could be like the London underground
Me too kid
@@5-Consecutive-Hairpin-Turns Life goals
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Hot, loud and deep?
@@mildlydispleased3221 or do they mean they want to let a train run through them? O.o
we got stuck on a central line station around 16:45 during the 2019 summer heatwave in london because the wires were melting and our train was delayed. we were absolutely roasting and the flow of rush hour commuters didnt help. people were starting to grab onto the belts of random strangers who stood the closest to the edge of the platform cos everyone was getting nervous that someone might be squeezed off the ledge
Another idea is... Heatpumps, that basically pump the heat into water tanks - which could for instance be used by buildings the surrounding area to heat their own water, amongst other things. The water solution would require smaller pipes potentially than the pipes needed for air extraction. Just pump how water out so buildings can then use said heat and replace with cold water.
Just suggested the exact same, give or take. How much does inner city london spend heating water, and how much extra electricity and gas does that use in winter, all while the Tube is using electricity to try and cool itself down.
You could really solve it in a kind of completely renewable energy way.
Photovoltaic Systems shading every above surface track.
Heat pumps that put excess heat of the tube into the district heating network.
Reuse old smoke stacks (maybe put a plastic liner into them) for self sufficient ventilation (air is drawn thru one smoke stack or one surface opening, heats up in the underground, hot air expelse itself thru the smoke stack [natural convection])
@@FreakAzoiyd I would tend towards combination of ideas but yes, they really should look at renewable energy based solutions.
Problem is there's no physical room for them.
I think the other issue is that the heat is quite low grade and thus not particularly useful. There is a plant called Bunhill 2, I believe, that captures waste heat from the tube and I believe there was an experiment to cool platforms with cool water through large metal heat sinks.
They just announced air cooling at several of the hottest stations a couple of weeks ago. Knightsbridge is the trial station. Its effectively a large air cooler, nothing special. That mixed with regen breaking trains in a couple of years should help bring the temperatures down on those platforms.
50 years late! This is not a crime becuase NO ONE REFEREES LAWMAKERS!
@@seankuhn6633 and you think it should be a crime because?...
@@seankuhn6633 except voters? also its a crime because.... you dont like it?
@@seankuhn6633 Erm, remember the French Revolution? The trouble is the British are not very good at revolting. The British get upset and then settle for a cup of tea.
@@thrillereighties8241 we've historically been very good at giving other countries reasons to host a revolution though
My first reaction to the solution is the Tibetan railway cooling method, so basically in the summer some parts of Tibet get above freezing, but repeated freezing and thawing are bad for rail tracks, so the engineers had to come up with some cheap way to keep the soil permanently frozen. (Deep foundations are expensive)
What they did is to hammer some 4-meter (13 ft) steel tubes halfway vertically into the ground, near the rail tracks, and the tubes are sealed and filled with a little bit of water.
During Winter, the warmer-than-air ground heats up the bottom half of the tube, so the water/ice inside evaporates and rises to the top half, where the cool winter air condenses them to flow back down and the cycle repeats.
During Summer, the pipes stop working because no water reaches the top, so the top half of the steel tube stays hot in the air, and the bottom half stays cool in the soil.
So they are basically large one-way heat pipes that cools the ground every Winter.
All it takes are hammering some long tubes into the ground, no digging for shafts, no power required, and almost no maintenance needed, so it's incredibly cheap. Though the London Underground would certainly require longer tubes than 4 meters for those deep lines.
That sounds like that wouldn't work for air conditioning. London is also quite temperate and doesn't have cold winters.
The problem that "Half as Interesting" hinted at, but didn't explicitly say is that heat is constantly being brought into the tunnels and being radiated into the surrounding earth, but not nearly enough of it is being removed, and the surrounding soil has been warmed for almost a century now, and is now reaching that constant 30°C, a process that took decades to happen.
Yes, trains would take heat OUT of the area as well, but they add much more than they take out; friction of the wheels on the tracks, brakes on the tracks, electric motors emit heat as they run, bearings emitting heat as they move, the sun warming the trains outer skins which radiates out underground, humans emit heat as well, our body temperature is 37°C, so any riders also dump heat into their surroundings as well, and the list goes on. Add that the clay content of the soil would act like an insulator, and exclude water (which would help transfer heat away), and that the tunnels themselves are so small that very little air movement is allowed around or between trains (trapping air inside the tunnels, and preventing any wind from forming within the tunnels), and you can see that the central lines are very good at trapping heat. Eventually they will reach some kind of equilibrium, but it hasn't done so yet, and even when it does, the entire like will be a sweltering oven, if it is even habitable at that point. . . .
Your Tibetan idea (though it is a very smart solution) acts more as an annual thermal buffer (releases heat in the winter, and the surrounding soil recaptures the lost heat in the summer), and won't work for the reasons I outlined above; in that the surrounding soil is already saturated with heat, and more is added each year. The Tibetan idea also requires a thermal gradient that is steep (ie ~7-8°C/meter, or 2-3°C/ft) to form and sustain a thermal flow using water; and the heat gradient in the surrounding soil is more like 1-2°C/meter (or ~0.5-0.75°C/ft); and all you would be doing is transferring heat deeper into the soil faster, not getting rid of it. They need some way to efficiently remove large amounts of heat across the entire line; which is usually done via vents in modern subway builds.
I'm not sure how they will be able to solve that problem without major changes to the line's infrastructure, and telling the NIMBY's "sorry, tough luck, we need to do these things whether you like it, or not"
If the trains are such a tight fit, why not use them to push air in and out of the tunnel as they move. I would think the stations could be cooled better. But maybe I'm wrong, I know nothing about London.
Unfortunately the phase change seems like an instrumental part of the function, it might still work in this situation but I would imagine it would be far less effective
@@arthurr8670 they do, put they also push sunlight and brake heat in.
That issue could be serviced relatively easily but would require a lot of work. You could install a cool water pipe system on the ceilings of stations and wherever they'd fit in the tunnels. It would be a lot of heat to then dissipate outside in heat exchangers, but it's possible. Additionally, it should be possible to shower the trains before they return in to the tunnels to reduce the amount of heat they carry.
Yeah, there actually are a lot of solutions to the issue. But they cost money and time. And they got wars in other countries to fund.......
First idea sounds good, but showering the trains would make the tunnels too humid. Would make it even more unbearable.
@@2MeterLP If they also positively pressurized the center of the system it would keep pushing the hot air out and it would take the humidity with it.
1:09 LMAO HEAT MOLECULES 🤣 I'M HOWLING
Yes, the IRT trains just dump heat out into the stations, but that means once your train comes it’s cold enough inside to keep ice cream from melting (if it’s survived the wait.)
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Until you get to the next station, at which point the doors open, all the hot air rushes in, and the trains go back to pumping hot air into the tunnels. So even when it's a nice temperature outside, it's hot in the tunnels, so they run the AC, thereby making the tunnels even hotter.
And more importantly it dumps heat into the tunnels which is the greatest safety risk!
Went to London yesterday and travelled around using the Underground. I can attest you it's a free sauna down there, especially when there's a heatwave above ground.
it massively depends on the line, most of them aren't that hot in my experience
Yep, TfL have, and still do, fail to see the relationship between overground temperatures and underground overheating!
@@seadkolasinac7220 All the deep level tubes are pretty hot most of the time. Only in January and February is it comfortable in my experience.
Especially there's a heatwave above ground - you've understood the message! Well done!
As past Paddington to Oxford Circus "enjoyer" I can relate. This part of Bakerloo line really puts bake in its name! The oily and dusty air at 30°C is quite special. How I missed cool draft in spacious stations and comparatively even more spacious trains of Prague subway.
I refuse to be lectured on what terrible beer is by the people that brought us Bud Light Lime
Hear hear!
The clay absorbs heat and releases it so slowly that the heat from the Victorian trains IS STILL IN THE ROCK so you can see how it accumulates over decades.
That's what TfL have been saying for years. then it was "It's the brakes" Before you pronounce please consider that these pieces of "information" haven't enabled them to solve the problem, or even develop any slight improvements.
As someone who lives in humid DC and takes the metro everywhere I would be devastated if I went to escape the heat from above only for it to still be so hot below.
The New York City metro is your absolute nightmare then. Summer in NYC is devastatingly hot and the stations do absolutely fuck all to cool down, especially around the ticket machines, and it is only when entering the subway trains that you can cool down. Problem is, the temperature difference is so great that you're assured to get a cold every time you take the subway.
Man you take DC metro. I wish you a safe trip. Hopefully you don't get in a crash.
Say, have they fixed all the chillers yet?
@@mygetawayart So why do they have the AC settings so cold in the NY subway? Set the thermostats at a slightly higher setting, making the trains not so icy cold, and in the process dumping a bit less heat into the stations, making the temperature transition from platform to train-car less obnoxious.
@@fordhouse8b it's not just the trains. It's a citywide problem that no one seems to be willing to fix.
Something to amuse American viewers: the people who clean the tunnels when the Underground closes down for the night are known as “fluffers” (as in they remove the accumulated fluff from the system).
I understand the word has a slightly different meaning in the States ….
There is a picture of American fluffers at 3:21.
That seems to happen often between American and British word differences
@@thePronto Well, another case where "thumbs up" works better, as does the liberal use of suction. Kinda redefines "lend a guy/bloke a hand".
Let's not forget how the Americans call "waist bags" a "fanny pack"...
And unfortunately fluffers in America are payed way more...
I work on British railway our biggest focuse at the moment is keeping the track in a running state we have 4 hours a night to grind the rail to make ot smooth so it doesn't wear away any quicker than it does because it's a nightmare to get equipment and rail down there we have to use manual labour only because we can't vent the fumes of combustion engine machines down there and the underground is costly most of the cables downthere are dead as in not connected because its cost too much time and effort to retrieve miles of cable
When I was there a couple weeks ago, the Central Line, Victoria Line, and Piccadilly Line trains were all so hot. I was sweating constantly. It definitely motivated me to take other lines and buses whenever possible.
Friendly reminder to anyone travelling on the central line that London is due to reach 35c or 95f this weekend. And that a few weeks ago it hit 38c or 100f.
It's tuesday and I want to die already
So it actually is cooler underground again?
So right now, due to us getting a lot of clouds and rain here, it's basically the same temperature this week in Phoenix and London...
Yes, the relationship between Tube overheating and heatwave is undeniable!
It’s literally so hot they’re thinking of using it as a fucking geothermal energy source.
If they do use it like that atleast it will cool the tunnel down pretty quickly
I used to live and work in London. I recall one occasion when I was standing at the top of the escalator from the Central Line platform (can't remember which station it was) and the draught of air coming up the shaft felt (and honestly smelled) like the hot winds of Hell.
1:14 Heat… molecules… 😠
SCIENCE!
You should take a trip on the rubber-tyred Paris metro lines. It's the same thing but with extra friction. Those get hot, especially when it's 40° C outside...
Montréal had the same problem as they use the same rubber-tyred technology as Paris. The french engineers they brought in decided to install heating in the trains because of the harsh winter, even though the system was entirely tunneled. As a result a conductor passed out due to the heat and crashed his train into the tunnel end wall.
I loved the Paris trains it was like going to a child's roller coaster, and they were 'cool' enough for me but I'm from mexico, so maybe that's why I have more heat resistance
@@binoutech I installed a heater in my kids' playhouse. It gets extremely hot during summer, but that has nothing to do with the heater as it's switched off.
Yes it's solar gain, which is the main emphasis of the video!
So it's more about outside temperatures than friction, which is the point the video is making!
Wouldn’t district cooling be an option here? Pumping cooling fluid / cold water into the station via pipes which absorb the heat and then cool it again on the surface.
Thanks for introducing me to district cooling. For those who don't know, a cooling plant uses refrigeration to chill water and pipes it to surrounding buildings.
Or use the hot soil as the source for district heating of the buildings above. Same principle but more people benefit
For that to work you'd need to find somewhere to build the cooling plant and there aren't many spaces left inside greater London where you could build it and pretty much all of the Zone 1 and Zones 2 and 3 Oyster card fare zones have been built on which would require building said plant underground which would be extremely cost-ineffective. A better solution would be to probably put the entire "Central London Railway" inside by putting a roof and walls on the above-ground sections of the line such as the stations west of Paddington and the stations east of Bethnal Green but this approach wouldn't look very good and there'd be some intersection problems especially with the District Railway and the Great Western Mainline which the Elizabeth Line uses west of Paddington...
@@wclifton968gameplaystutorials hm, couldn't they build it in the Themes? All that water would make a good place to dump the heat into.
@@wclifton968gameplaystutorials I have to ask as someone whos only ever ridden the NYC subway, What are the zones I hear about on the Underground? Does the charge differ based on where you enter and exit? vs one charge to enter and then the tunnels are yours to roam(on a train of course). NYC its one charge to enter and then you can go anywhere on the system, So you could start way the heck up in the Bronx and ride all the way to say Coney Island for the same cost as riding to Times Square.
Air conditioning is one of the rare things Australia has had before it was cool. The first fully air conditioned trains we had here in a particularly hot part of the country were first built in 1952. The first commuter trains in the same part of the world were 1978. It gets so hot here that the air conditioning is partially redundant, with two 30kW units per *carriage.* To put that into useful figures, the air conditioner in your living room is probably 5 kW.
I guess be thankful that these trains aren’t on the central tube line.
The New York Subway has Air-conditioned trains for 30 year, but it still overheats!
@@BB-xx3dv If you’ll allow me to split hairs, those are interstate trains, whereas I was talking about the first local commuter trains. The S sets weren’t air conditioned (apart from the drivers/guards cabs). You might be right about the silver bullet but was this class-based? Like only the higher classes had air con? If so, the sunlander was the first train to be fully air conditioned. Edit: no, no classism here, so you were right about the silver city comet. The sun lander would have been the first air conditioned train in Queensland.
@@BB-xx3dv True, but were they used on runs in Sydney, or just out to Newcastle, the blue mountains, etc? The QR EMUs weren’t built to be long distance trains, which in my mind makes them the first local trains to be air conditioned. It’s splitting hairs, I know, but it’s nice to be first at *something*.
"Air conditioning [...] before it was cool".
Nice job with the wording 😂
Whats the point of having air conditioning before its cool? :D
@2:34 I appreciate the attention to detail in using stock footage of a UK style outlet. I'm not even that into outlets or anything- but I gotta respect the hustle
Small problem at 3:05. Isambard Kingdom Brunel had been dead for 31 years in 1890! Truly one of the great engineers of all time to design things from the grave! 😀👍
Also, 1890 was the opening of the City and South London Railway, now the Morden branch of the Northern Line. The Central London Railway, now the Central Line, opened in 1900.
Being dead didn't stop Shakespeare giving us West Side Story, The Lion King and Forbidden Planet.
Brunel was present as a representative of engineers, not as the person responsible for the underground. In the same way that you no longer save files to a floppy disk, but it remains the icon for saving.
@@al201103 Yeah, I get that. Just like the laughing emoji and thumbs up signifies a JOKE about Brunel designing things from the grave. 🙄
Even if he were around, TfL wouldn't listen to him!
They should install full height platform doors to every Central Line station so that the platforms would be sealed from the hot air until the train actually stops at the station. While this doesn't help people inside those trains (until they figure out a way to cool them), it would still be much better for passangers waiting at the platforms. This works really well in Singapore and Tokyo (especially during summer). Of course the stations would still need cooling, but that shouldn't be too difficult.
Can you not suck the hot air out of the train when docking at a station. It would heat up again until reaching the next station but should be manageable.
I strongly support that, and as a person from Seoul I find it hard to believe that most tube stations don’t have platform edge doors. However, platform edge doors are actually tied closely to this ventilation problem, and it’s more serious for the deep-level tube. Essentially when installing platform edge doors, it is necessary to have plenty of ventilation from the track side, because otherwise the doors will get damaged from the tunnel wind when trains arrive. With deep-level tubes this is much more difficult to fix because basically trains fill the entire surface opening of the tunnel, pushing all the possible air in the tunnel through to the platforms. If I remember correctly, this was actually part of a design for ventilating stations, where the air pushed from the tunnels will travel through the station corridors to ventilate the platforms. Installing platform edge doors would thus also interfere with this design, and make platforms stuffier - so they also need to put much stronger ventilation in each stations. Lastly, the platforms on deep-level tubes are tiny so putting doors there would make them really narrow. Although from the safety point of view, this is only another reason why they should install the doors cause people do fall on tracks in london because of overcrowding.
Its not possible. For one the platforms are old and not designed to hold up the weight of platform screen doors, and a lot of the platforms are curved which poses an issue of people getting trapped between the train and the PSD
@@artursdobrecovs Hong Kong Central Station is curved and has platform screen doors
@@supernt7852 nowhere near as curved as a lot of Central line stations - ever been to Bank?
"Heat molecules"
Also, why not run the metro's with an inverted airco on the places where the clay is too hot and vent that heat on the platforms which can be cooled?
Or idk use watercooling around the edges of the clay.
Or have 1 car every hour do the inverted airco thing, but let it be empty of people and full of water. Then cool the metro's at an unused station
Just run the cooling trains overnight.
You don't need to cool the line over the daily cycle, It has taken decades to heat a few degrees.
A further problem with the Deep Tube Network is London has a lot of clay under it and it doesn't conduct heat well at all, so it insulates the tunnels and keeps the heat inside, compared to other Tube lines where the earth around the tunnel lining absorbs a noticeable amount of heat.
This is a Red Herring. Clay does not cause the heat. In fact TfL's monitoring of the clay shows that the temperature near the tunnel was is seasonal - so cause mainly by the trains being irradiated on the surface and acting as giant radiant heater heating up the tunnels.
@@calvinbarrows3018 Didn't you just say the same thing as the "red herring". Clay does not conduct away heat, so its temperature varies seasonally, at least close to the walls. More conductive soil disperse the heat from inside the tunnel and change temperature less.
@@Allan_son The point I am trying to make is that its not so much about how the clay reacts to the heat, it about where the heat comes from. So for Glasgow, Warsaw and Prague what surround the tunnel is of little relevance because these networks never overheat!
How did you come to that conclusion? It doesn't square with the Cockram and Birnie findings!
I was in London recently at Oxford Circus station and changed from the Bakerloo to Central platforms, and walking into the staircase it was like walking into a wall of heat. Give me a subsurface line any day.
The central is cooler than bakerloo by every metric
Mind you even Sub-Surface Underground lines become extremely hot.
@@PSYCHIC_PSYCHO they don’t? the trains are super nice and cool, what did you go on?
@@axethepenguin I wasn't commenting about Sub-Surface S Stock trains, I was commenting on tunnelled stations below streets, and the recently scrapped Sub/Surface trains
@@PSYCHIC_PSYCHO Ah I see
Imagine being from a cold country coming out of the central line in the middle of a British heatwave then go into a taxi with someone who likes to crank the heat all the way up and all of that is happening when you are very VERY sick and sensitive to heat
They probably did that to prevent the car engine from overheating. I've had to do that on occasion.
Are you projecting
"Atleast you are not going to be in DEBT after the heat stroke"
@@mewmimo8465 heat strokes*
@@katbryce A lot of cabs in London these days are electric so I'd hope that's not still the case, but maybe it was a beater I guess
Really good explanation, and good to see recognition of the problem that aircon itself generates more heat than the cooling it achieves, which often isn't realised. Very interesting about the trains brining heat into the tunnels too on a hot day! And that the tube lines are inherently less well ventilated than the subsurface cut-and-cover ones.
Until about 10 years ago there wasn't any air conditioning on any of the tube lines.
Air condition the stations, and have some of them work on overpressure and others on underpressure to ventilate the tunnels. Gradually suck the accumulated heat back out until the temperatures stabilize at a pleasant level.
Weird you missed out on the most likely suggested fix for this. Most of the tube network is at or below the water table. I'm pretty sure (doing this from memory instead of googling it) they have pumps running in parts of it and I definitely remember a news reel where they went down some access tunnels, lifted a cover and there was tons of water flowing by.
I think the plan is to use that water to cool parts of the tube. They could run pipes up the tunnel to the entrances to the circle line and spray the trains down as they come in - a long pipe, sure, but they already run cables along there. The lines are already designed to deal with rain and wet trains, it wouldn't be hard to run sprayers and put in an extra drain in under them.
The same natural water could be used to remove excess heat at stations too. All you have to do is line tunnels or stations with metal water pipes across the ceiling (where it's hottest) pump water through it and let it either drain back into the same flowing water it came from or submerge the pipes back into the water and let them radiat their heat into the water. The flow of water will do the rest. If you need it to be cooler than that, pump the water to a location where you have a ventilation shaft (one of the other connected lines) and install a refrigerator system at that location and move the water back via a well insulated pipe. Over time the pipe itself will become very cold.
Weird you weren't aware of the water level suggested fix. I think the reason they haven't done it is the cost.
That would honestly be a great idea though. This video seems to not mention the clay around the tunnels getting really hot, which then stops any cool air coming in (if there is any). Water would probably cool down the clay
They also have an alternative version of that poster advertising it is warmer in the Underground and you can get out of the rain.
This is true of underground only networks, but not mixed u/G, o/G ones
I know a lot of this. I chose this subject for my dissertation about 10 years ago.
I wasn't aware of the heat absorption from travelling in and out of the tunnels though.
Nice. There's always something to learn.
though the brakes are as far as I have found the primary factor.
Yo 🔥ruclips.net/video/rdJ9bsN7JAw/видео.html
@@xander1052 Or in NYC, the train air conditioning is number 1, with brakes being number 2.
@@xander1052 there are, but it's not the only factor. It all adds up.
There might be an unintentional solution to this. As buildings move away from gas powered heating to heat source pumps. If ground source heat pumps were to be used, it would extract far more heat from the soil than the tube uses, cooling the tube.
Interesting idea
The one downside is you can't flip the inversion to cool off the houses during the hot summer months as that would roast those on the tube even more. But if the government would give subsidies for an alternative cooling solution to be installed for those few months then it would certainly be a way to help both the tube, the environment and with the gas/electrical bill for real-estate owners.
Since most of the tunnel is covered by building, installing GS heat pumps would not be feasible!
@@calvinbarrows3018 obviously you don't need to get near to the tube to get the benefit, that's the point. The whole of the mass of earth has warmed up.
@@gwendragon6419 Since clay is a bad conductor of heat, I would disagree. Anyway what do you think is heating up the clay. Cockram and Birnie found it was seasonal, which TfL have never noticed!
What about water cooling? I'm only half joking here. I found a recent open access (free for everyone to read) paper discussing the possibilities: "Cooling the London Underground: Evaluating the use of groundwater and subterranean river water".
They've done this already at Green Park - it wasn't a great success!
I would like to take a brief moment to thank the giant vents at St. Paul’s Station WB Platform Eastern End for not roasting me alive on that one August night in 2019
I had a commute from West to central London via the central line. I got so fed up with the heat and delays that I started cycling.
My journey is 10 minutes shorter, no delays, I'm fitter, it costs far less and I'm not nearly as sweaty as I was.
I couldn't imagine going back to being packed like a sardine and paying through the nose for the "privilege".
Jeez, you know it's bad when actual exercise makes you less sweaty than riding a train
And there’s a strike tomorrow woops
It's hardly "paying through the nose", the tube is pretty cheap. That said, well done for cycling!
The Elizabeth Line would change your experience. I've tried it and it's fantastic.
Calling cap
What station you board
Many years ago, I worked on the design and construction of the Victoria Line and in particular on heating and ventilation. In doing so we took account of several factors that were problems in older tube lines.
The first of these was the draughts caused by the passage of the trains blowing air into the stations. This was alleviated by building cross-passages between the two tunnels and close to the stations large shafts were built taking tunnel air to open air. These solved that first problem and, partly, the second problem.
The second problem was the heat output from the trains, the lighting in the station, the ventilation of the surface and underground building, other station services and, of course, the passengers. To alleviate these heat gains large extract fans were installed on the system and between stations and these drew fresh cooler air into the stations and platforms.
What could not have been envisaged was the vast increase of the number of passengers and a train service of one train every 100 seconds. Even so, the Victoria line seems to be one of the coolest of the tube lines.
I’d like to disagree 😭😭😭😭😭 They’re boiling
as someone who uses the Victoria line daily, it's probably one of the hottest and stuffiest lines. There was an article last year that even recorded the Victoria Line as the hottest of all tube lines
The stats show that the Victoria is the second hottest after the Central and it has goit noticeably worse since the new generation trains replaced the 1967 stick; better acceleration and braking, plus higher service frequency. It incidentally derails part of his thesis about open air sections worsening the problem; the Victoria is 100% underground.
The ventilation tower outside the Pimlico station on the Victoria line is a really cool sculpture.
By far the biggest heat source is people. Back in the 1800s the population was a third of what it is today, and people tended to live where they worked more. Put a few hundred 37 degree heat sources in a confined area and it soon raises the temperature. Part of the reason central line tunnels are so tight is that trains were supposed to act as pistons to move air, but now with platforms packed tight for hours a day, it is ineffective.
02:34 Would just like to appreciate the use of a stock vid of a British plug at this point! That felt good in my brain
The whole "AC will make the tunnels hotter" problem is exactly why the Montreal Metro isn't Air Conditioned. It uses rubber tires on metal guideways, because Quebec really misses france, but if they strapped AC to their trains, it could make the tunnels too hot for trains to even work, I guess they're worried of the tires melting?
They should just bite the bullet and use steel on steel. It's far more efficient.
@@TalesOfWar Right?
I was on the Montreal Metro and it was VERY HOT. That was many years ago, sounds like nothing has changed. You could feel the heat blazing out from under the cars. Who in their right mind would put trains on rubber tires? Just plain stupid.
@@AlexA-nd3yy Now, granted I haven't been on the Montreal Metro, this is just what I've heard. And there is a traction and smoothness benefit... but that's where that ends, that traction comes from friction, friction means heat, wear and inefficiencies... Plus I've been on Subways and trains with normal steel on steel... they're pretty damn smooth on their own, I don't need rubber donuts to smooth it out more
@@coastaku1954 I agree, with steel rails in good condition the ride can be very smooth. The Montreal Metro ride was very different, very bouncy ride that I found quit unpleasant. But it must be noted it was a long time ago I was on it, and may be different now.
One way they could make it work would be (really long) coolant lines running along the tracks, with very small radiators and fans acting like very small air conditioners, but for the entire length of the track. Due to a passing train only being there for seconds with several minutes or more in between, it would EVENTUALLY start to catch up. Or even if it never caught up it could at least mitigate some of the heat buildup so it doesn't keep getting hotter while they actually figure out a way to redesign the tunnel
There's zero chance of the tunnels being redesigned. Just impossible. If you've been there you'll know what I mean.
Oddly enough these short format videos have actually forced me to look up extra info on topics than a lot of long turn videos.
Not always but i noticed that i find myself playfully frustrated and then running off to learn.
So thank you i guess? Also god damn you and your short attention span appeasing content!
Nice to see Ben writing this week's script, it's been a while
How can u tell?
@@spencerparsons5212 Adam’s jokes are much more extravagant and emotional than Ben’s, plus Ben gets credit in the description of the video.
@@finnrummygaming ur a genius. damn. also, i really thought that Sam was the brains behind the UK based videos as he lived here for several years. he might still be the one coming up with the initial ideas though.
@@finnrummygaming the jokes are all cringe and distracting
I would say, heat pipes. Take the heat from the tunnels and funnel it into small active cooling towers above ground at the stations. Not as efficient as simply more ventilation shafts, but if you really can't dump heat out anywhere else, you're going to have to get that heat through and out of the stations. Thearhetically, you could see about the trains somehow storing heat as it goes through it's route, and dumping it out at stations, but that seems more ridiculous than copper heat pipes going the full length of the tunnel.
Heat pipes are made of solid metal. In other words, they are really expensive
If there's space to install heat pipes then there is space to install refrigerant pipes for active systems that would be more efficient.
@@kalebbruwer heat pipes are often fluid filled...
@@calmeilles you mean "more affective", by definition, an active system cannot be more efficient than a passive system.
You may have over estimated the amount of cooling required as well. A passive heat pipe system would do the trick, and have near zero operating costs.
What about ventilation shafts with a perforated lid on top. The heat can dissipate from roads instead.
This is why when I did used to commute to Central London I always avoided the Central line. The heat plus the over crowding was appalling. I see others have mentioned the Elizabeth line. One of its justifications for being built was to take load off of the Central line and it has made some peoples' journey a whole lot quicker and cooler!
Yes I've tried it out and it's fantastic. Also it follows the Central Line in many places, for example Ealing Broadway to Stratford can be done on the Elizabeth Line instead of the Central Line.
Even after it’s completion, even in my trips, the Elizabeth Line doesn’t get many passengers and you still have problems with passenger overload.
Even the Jubliee Line gets pretty packed on weekends.
One thing that is being investigated is using that heat to power surrounding buildings. There is a pilot unit in use that I have heard is proving quite successful. It should be possible to use existing access points for pipe work, although work may need to be done to fit heat exchangers at track level. While this may not COOL the lines that much, it should reduce the INCREASE in heat, and have the benefit of reducing heating costs in those buildings above ground.
This sounds like a job for Mr Freeze
I hope we see Sam grab a cheeky Nando’s in the next season of Jet Lag
0:41 "This is about stuff heating up here" (in the London Underground)
Map: Arrow pointing at the very middle of Africa
If they've got drainage in the carriages and tracks (they must have?), they should give people entering the station a 1kg donut of ice on a loop of sisal or something to drop into a tray on the train. More people, more ice. Let it drip through the floor into the drains. Collect the loops of sisal occasionally and bring them back to thread around new ice donuts.
I feel like the simplest solution would be just having cold water lines added into the tunnels, possibly with radiators for extra passive cooling or bonding it into the tunnel walls/ceiling. Intake of the pipe on the bottom of the Thames where it's nice and cool, outlet at surface level, and just dump waste heat into the river, OR loop em back into stations and throw a big swamp cooler on the roof. Would be SLOW, not immediate, but eventually in tandem with regen braking and such, to reduce heat output, it oughta cool things back down to soil ambient eventually.
It would clog up with gunk over time if it's coming from the Thames.
With all that heat dumped into the Thames, it would soon be colonized by crocodiles and coconut palms would displace the plane trees lining the South Bank.
Perhaps use heat pumps. If a nearby building wants heat for water heating, they can install the evaporator in the head space, and otherwise mount the compressors and condenser in their own basement somewhere.
This is a very good idea in principle and variants on it have been suggested by lots of other commenters. The snag is that the temperature difference between tunnels and cool water is really not that high, so you need a very large surface area to transfer any significant amount of heat. Basically even finned pipes won't manage much, you need really giant radiators - which unfortunately won't fit in, and would be very expensive.
God I hate the underground's heat.
It got so bad one week that I just paid for taxis to and from work.
I was in London twice in my life and somehow did not notice that it was especially hot.
Born and raised in London and I simply will just walk now to avoid the central line as it’s way too hot.
Imbed pipes in the walls of the tunnels parallel to the tunnel, or "glue" them to the walls of the tunnel. Pump cooled water through the pipes to remove the excess heat. You might be able to use a simple heat exchanger like a car radiator during the winter to cool the water in the pipes. Or divert some of the cities water supply through said pipes to absorb heat and return it back to the water supply on the other end. A more energy intensive solution would be to use a heat pump to cool the water.
Yes, this could be done. It's a very long term solution though - there's a century worth of fossil heat down there.
Not all the route of the Central Line is massively developed. It runs along the north side of Hyde Park, and under the very large traffic island at Marble Arch, both of which could be potential places for ventilation shafts.
It runs right past the bank of England's gold bullion vaults. Vent it into that and offer free smelting services.
@@SmokeyBCN Bank Of England
"Whomsoever Smelt It, Dealt It"
More ventilation shafts is not a option since ventilation is not cooling!
Let's use the space for heat pumps then! Pump all that heat out
Regenerative braking send like such an obvious thing for an electric train, too.
I imagine all the actual people on board are also kicking out a good bit of heat, though.
Even TfL now think passengers generated heat is not a big deal!
as someone who works with horses, the shafts dotn scare them, the noise from the train and the fact theyre in a small, confined space with nowhere to run away from predators dkes
can confirm the central line in summer heat is awful. its uncomfortably warm in the dead of winter sometimes let alone when we have a heatwave and entire population of london is trying to squeeze onto your carriage
Especially because it's heated and you've got your winter coat and scarf no;
*on
I was on the Tube on Friday (2022-08-12) during the heatwave and it wasn't that bad. The cabins weren't cold or hot. I think most people will be okay for the time being.
As a brazilian in one of the coldest states here, 30°C is only a little hotter than usual, and 19° is considered pretty cold.
Possible solutions:
Bore a parallel pair of tunnels, one of which is fed from both ends with cooled air and the other one being used to vent hot air to atmosphere, and then just connect the tunnel(s) used by the main line to that new pair of tunnels with ventilation shafts and valves.
The portions of track running above ground, cover them with if not solar panels, reflective material.
Paint the trains with paint that isn't just reflective of sunlight but emissive at temperatures of at least 60°F to 140°F. This will have the effect of increasing tunnel temperatures but decreasing temps inside rail vehicles but unlike using A/C it would do so without increasing the total heat energy in the system.
I love that 86F is considered cruel and unlawfully hot. Now lets terraform earth to keep every inch of the surface below that temperature at all times please
I bet Nando's doesn't actually have that policy.
Nandos worker (nandoca) here: they don't, given the ovens used to cook the chicken are steam ovens, I'm sure they'd be glad for some more.
The primary source of the heat is not friction, it is the the conversion of electricity into motion. The old school direct current propulsion systems used resistors to control the traction motor voltage that powers the trains. Those resistors produced a great deal of heat along with the windings in the traction motor. The same conditions exist in the modern alternating current propulsion systems as the power electronics used to control the voltage and alternating current frequency also produced heat along with the traction motors . Heat from friction braking is a small compared to to the heat generated by the propulsion systems. Heat from wheel rail contact is almost nonexistent as there is very little friction.
I believe the Central Line's braking is electric down to slow speeds before the friction brakes turn on. It has the highest acceleration (and highest braking) of all the London Underground lines, and to think they have only ever used the lower of the two accel/braking levels available. The congestion between trains in the peak periods causes the trains to accelerate and brake quite a lot, because in part of the hybrid fixed-block signaling and ATO, and it so happens that this bouncing between speed commands was much more frequent than was ever expected - due to a lot of incorrect assumptions made by the engineers. They thought most trains would see a free run between stations, it turns out to be not true. Lots of other decision-making throughout the Underground failed due to the same assumptions.
I love how unique you make these informative, educational, true, and funny videos! You're like a god!
As an Aussie I'd much prefer a 30C temp to 14C.
Piping water through the tunnels in the space between the tracks would allow for a lot of heat to be moved without using any additional space. Each station could have a radiator section that circulates air through it to drop the temperature specifically in the areas where the passengers are and it's also where the brakes and motors will be expelling the most heat.
The paraphrasing is absolutely brilliant.
Keep in mind these trains use a 4 rail system, so the space between the running rails is occupied. The reason for 4 rails is to mitigate galvanic corrosion in the tunnel walls (or nearby plumbing) from the massive induced currents from the traction motors. Its a very tricky thing to stop. Any conductive cooling fluid could add another galvanic circuit to counteract, plus any radiators, fans, and electrical conduits. The Department of Unexpected Consequences...
Yes, 14 degree Celsius is too cold !
Perhaps they could use this heat resource? How many buildings could use a heat pump water heater to pre-heat their hot water? Drill to the tube, install the evaporator in the head space (make it long and skinny), and install the compressor and condenser in the basement of the building that wants it?
It seems that london has a thing making unwanted heat, and endless buildings paying good money to generate heat, they just need an easement to connect the two.
One of the highest contributors on a tube train is the disc breaks. So one solution could be to use regenerative breaking systems, avoiding the friction generated heat and saving power by reusing it. Plus the surface sections could have solar panels installed above the tracks, no heat absorption and again more energy generated.
The new 2025 stock for the deep level tube will have regenerative brakes.
Not true about the brakes
@@calvinbarrows3018 It depends on your assumptions. If you're asking whether the regenerative brakes will produce no heat, of course that's false. They do still produce heat. If you're asking whether they produce significantly less heat, that is true. They generate electricity, and that doesn't come from nowhere. Brakes produce heat as waste from the friction interaction eliminating kinetic energy, and in a train there's a lot of that. Regenerative brakes draw off both electricity and heat as products of the braking, like splitting the flow of a river into two, and so the regenerative brakes produce less heat.
I don't know how MUCH less. But it's significant, as indicated by the large amount of electricity produced.
@@googiegress7459 I don't disagree with regenerative braking as a means of recovering energy, but most seem to be getting tied up in the detail and missing the main message in this video - the effect of carry in heat! This effect was identified by Parson's brinckerhoff and many of the leaders of the US Rail Industry in the mid 1970's, so its not a new discovery, it just got lost in the mists of time!
@@calvinbarrows3018 I'm working off the well-established thermodynamic law of conservation of energy. If you wanna argue, cite some damn good sources (legitimate ones, not crackpots), and I'm open to learning.
4:10 “scientists invented friction” -half as interesting
Experienced Central Line riders will tell you: the best place to be in a carriage in rush hour is not the seats, it’s the small bit of standing room right in front of the open window at the front of the carriage.
NYC subway stations are noticeably hotter than the outside temp, its actually insane how dangerous it can be down there in the summer
been to new york with the family in August 2016. The heat in the stations and around the ticket machines was just too much to bear and the temperature difference between the scorching platforms and the freezing trains only made sure we came down with nasty colds afterwards. Not that the temperature difference between the streets and the insides of buildings was any better. Americans go insane with AC, no wonder the air outside is so hot.
If they just turned off the AC on the trains in the central underground portions, and instead installed AC in the stations which actually moves the heat outside, they'd have a much more pleasant environment with the same amount of electricity.
1:09 Could you please clarify what "heat molecules" are and what atoms they are made up of? I never learned of such molecules in my friction class 😋
If we split heat molecules into heat atoms would it make the problem better or worse?
@@dundeemink3847 Probably endothermic
I run a dog meet-up group and we can’t meet during the summer as the tube is far too hot for dogs to travel.
Idk how many ventilation shafts there are. But as long as there are at least some, this is a completely easily solvable issue. 1) increase the volume of air moved by installing bigger more powerful fans pushing air around and 2) install ducting to better distribute the higher pressure air. Ur welcome London.
The trains are basically a square cross section and the tunnel is basically a circular cross section. You can put pipework along the sides of just a few tunnels and water cool the stations, while also providing cheap heat to local residents. The whole project requires about 2 holes, a few 100m of copper pipe and a pump, and you get to cut heating bills.
The reason these trains have curved roofs is they *conform* to the shape of the tunnel. There is also signaling, communication, and power cabling covering the tunnel walls. There is literally no space in the old tunnels, or dangerously narrow station platforms. The best *partial* solution is to fully widen the tunnels, while the trains run, at a staggering cost like the CrossPurpleElizabeth line. Now that you have space, you'd still need something at the surface to dissipate the collected heat. It's a wickedly tricky proposition with a colossal price tag.
The small tunnels are the reason why deep tube trains have a basically circular cross section...
The editing on this video is fantastic. Also, I had a pretty visceral reaction to your usage of emojis to represent hot and cold. I feel old.
This is probably the first time I am seeing the red hot face emoji with the tongue sticking out to represent temperature. Usually it has other "implications".
I'm pretty sure that was the joke, and I was a little uncomfortable at first too lol
"Heat molecules" has too much for me.
Coming from someone that travels to london a lot the tube seems to get warmer and warmer every time I go
The heat has sunk into the walls over the decades, so the walls are acting as radiators, emitting the heat they have previously absorbed. Perhaps if the line was closed down for 20 years, allowing cooling of the tunnel walls we could get back to the original 14 degrees, for a short while anyway.
Even closing for a week and pumping cold air into it from all station would drop the temp a lot. They could have done that while Covid during the passenger rate dropped.
We probably could because the thing that creates the heat will not be operating!
They just need to increase the velocity in the existing ventilation system, and maybe cool down the intake air. Or, for much more heat transfer, run refrigerant tubes through a little part of the existing infrastructure. Or just chilled water or water anti-freeze mixture. It all does cost money. And energy.
Water sprayed over the cars as they are about to go underground and just after they emerge may not be perfect, but it would help. The water can also be at least partially captured, run through a settling tank and reused.
@@Skeeter51244 Do you mean train?
@@kylenetherwood8734 train cars
@@kylenetherwood8734 trains here are comprised of multiple cars, back to Churchill's "Two nations separated by a common language."
Or something ;like that.
I've always called them carriages. I was just asking for clarification though, not trying to correct anyone.
Central line is the Hell line - it's red, hot and crowded
To survive a trip on the underground, put 40 kg of crushed ice in your rucksack. Is the heat in air that is 25 C to 32 C harvestable for anything, such as pre-heating hot water ?
Sounds like a great source of geothermal heating for any structure above it.
Life is weird. We have the issue that we desperately need to produce more energy without fossil fuels. At the same time, we have the issue of there being too much energy in the underground.
If there was a cheap and efficient way of turning heat energy (at around 30°) into electricity, we would solve many societal problems.
If only, but alas, thermodynamics is a bitch
Well, the Stirling engine converts temperature differences (like between the Central line and the surface) into mechanical energy, which can be turned into electricity.
@@Anonymous-df8it If you could get the heat to the surface then you would not have a problem with the heat in the tunnels.
@@madattaktube what does this have to do with thermodynamics? no one is suggesting we make energy from nothing.
@@catboyedgeworth2469 Energy in the form of heat is intrinsically less useful than e.g. kinetic energy or electricity; you can look up Carnot's Theorem for the actual physics. Even worse if the temperature isn't very high, e.g. 30 °C tunnel vs 20 °C outside.
When you see your station pop up multiple times in the vid and you feel wayyyy too proud 🤣🤣
Easy solution. Install big fans at the entrance and exit of each tunnel, and have them blowing in the direction of travel. Hydraulic rams automatically lift them out of the way when a train approaches, and drops them back into place after the train has passed. The tunnel will permanently have a breeze blowing through it.
So if it's already too hot for transporting livestock, at what temperature do they cut it off for humans?
100c
When there won't be any people using it a.k.a "PROFIT"
38°C.
Planck temperature
The solution is simple (if pricey), since it can’t vent to the surface, vent it underground, to a new ventilation tunnel, the ventilation tunnel would then run to a less dense area where it can cent to the surface, blowers would be required to keep the air moving through the tunnel. Alternatively, it could be vented to other lines which are already vented.
I think part of the problem there is that the tunnels are too small, being just big enough for the trains.
One way or another, this is going to be an expensive, probably unpopular (at least in the short term when it is quite expensive and shuts the train down) big construction project to fix a problem that, for the moment, is an inconvenience and not a serious hazard. Humans everywhere have demonstrated that they are unwilling to take measures to fix a problem until that problem forces their hands. The more expensive the fix and the more inconsequential the problem, the less likely it is to get fixed before it absolutely needs to be fixed. Welcome to politics.
Vent it to the surface, to a road. But then, put a perforated lid on top of the vent to stop cars from falling into it.
That would be as expensive as building a new line!
@
Yep, I said it would be simple, not cheap, but I don’t see anything else working. That’s why I suggested the alternative of venting in to other already exist.
@@cplinstructor What about my suggestion?
I live on the Central Line and I avoid it unless I have absolutely no choice. In addition to all the issues listed in the video, it's one of the most popular lines for commuters, so everyday before and after work it is stuffed full of people, which also adds to the heat problem. I'll have no problem adding ten to 15 minutes to my journey by taking a bus instead.
Sounds like a problem a big portable heat pump could fix. Compress refrigerant outside then drive the heat pump with the compressed refrigerant into the tunnel and decrompress it making it very cold and eager to soak up all the heat in the tunnel. Then drive the heat pump outside again and repeat.
It's all be said before! Look at some of the previous replies!