"The average temperatures on the Victoria line have risen by almost seven degrees since 2013 – nearly a *30%* increase.
Conversely, the increase in the average annual temperatures across all Underground lines from 2013 to 2024 was merely *seven percent*, placing Victoria’s temperature rise vastly above that."
Using percentages to talk about changes in non-Kelvin temperatures is crazy.
28 degrees Celsius is not 30% warmer than 21 degrees Celsius. This same stat rendered in Fahrenheit would say 70 degrees -> 82 degrees, or 17%. In kelvin it would be 294 -> 301, or 2.3%
Or we could invent a new measure indexed to Celsius but offset by 20 degrees, and declare a 1 -> 8 change, a whopping 700%.
You see the opposite effect with reporting on the DJIA, where a 500 point move is treated like a big event even though it's is not nearly as significant today as it was 30 years ago. They ignore the more relevant percentage change in favor of the more sensational representation.
Even Kelvin is the wrong model. What we need is temperature, humidity and air speed to interfere anything meaningful. ISO 7730 is even more precise. Any meaningful discussion should use the models from there.
Feynman was complaining about this error appearing in textbooks back in the sixties[0].
The trouble (of course) is that Celsius properly is not a proper unit, but a "scale", or a "unit of difference" (equal to kelvin), or even torsor[1].
The trouble with the kelvin here is that if you see the 7 kelvin increase as a proportion of the 295K starting temperature the you only get a 2% increase. Nobody is going to buy your newspaper if you're putting up weak numbers like that.
To make matters worse, not all ranges and percentages on that scale are equal, whether they're the same in absolute or relative terms. Humans have a narrow relevant "operational" temperature band. Even 20 degrees between 10-30C feel like nothing compared to the 5 degrees between 37-42C.
There are few or no human scale situations where percentages of absolute temperature are meaningful, absolute zero is too far away and we live in a too narrow range of temperatures. Unless you're in a scientific context just don't use percentages on absolute temperature, only on rates.
People who complain about Fahrenheit vs. Celsius are correct to the degree (sorry) that the Celsius degree unit of difference is the standard in a lot of engineering calculations. But Celsius as a temperature scale is no more logical than Fahrenheit, which is arguably more practical for day to day use--and Kelvin is more likely required for a lot of engineering and chemical calculations anyway.
It would definitely be crazy in Fahrenheit, but in centigrade I think it makes some sort of intuitive (if not scientific) sense. (Together with the sea-level assumption we always make in casual temperature discussion anyway.)
In both it makes a sort of intuitive sense. 7% of the way from freezing to boiling is a meaningful way to visualise temperature; 7% of the way from ice melting in a bath of salt to slightly above Mrs Fahrenheit's armpit temperature is also meaningful, although perhaps a little idiosyncratic.
Edit: this comment was deeply stupid for obvious reasons and I regret trying to interact with other people when I should be asleep.
And they manage to make it even more crazy by also comparing it to average external temperatures.
==
The Victoria Line average temperature in August last year was 60% higher in temperature than the average external temperature that month, measured at 19.5 degrees.
==
Certainly for January it must have been hundreds of percent higher.
And what would the numbers be for e.g., the Moscow metro in winter months where the average outside temperature is negative?
Yikes. I posted this, and I missed that, something I realised soon into my first year physics degree lab. I learnt more than just dipping calculators in liquid nitrogen for fun.
Maybe the right thing to do is to measure from ideal room temperature? From zero doesn't make any sense but setting an anchor temperature makes sense.
This is done when people rate the efficiency of home heating: SCOP is a function of the heat pump's ability to hit a particular temperature, for instance.
I'd guess the baseline temperature on the tube should be 21C maximum. Percentages don't make sense here, but 7C over the target temperature (for instance) is pretty bad in those terms. I'd be surprised if TfL hadn't set that somewhere.
Also worthy of note is that it sounds like the tube is a prime source of heat for a district heating system. Win win, perhaps.
I don’t know if I’m worried about it. While the measurement makes little scientific sense it makes intuitive sense, and, importantly, the intuitive implications are the scientific implications.
It’s a huge increase, if not for the reasons they describe.
Is it? I think it puts the Victoria rise in perspective to the other lines quite effectively.
Everyone knows where the zero is in Celsius using countries anyway and days in the negative are so rare in the UK you can discount them (plus they are none inside the tube).
Looking at the temperature chart and the significant drop in 2020 during the pandemic, the source is certainly the trains and people themselves. (fewer trains moving, less heat added back then). At this point I expect the infrastructure is heat soaked and will need a prolonged period of cooling to bring temps down. i.e. don't expect instant results.
Moving more air through the tunnels, adding A/C systems - both have a problem of needing room up on the surface for blowers and compressors, something that is hard to do in modern London. Tough problem.
I wonder if they can carry hundreds of opened barrels of ice on open-bed trains through the tunnels at night, go slowly and let them melt to water (but kept in the buckets, because you don't want to flood the tunnels)...
I would expect them to already have some kind of drainage system, so if the line has some connection to some line that goes outside, just pulling cargo trains full of ice down there and dumping them might work.
That said, a typical shitty single-hose monoblock air conditioner has 9000-12000 BTU/h of rated cooling capacity. 12000 BTU/h is also known as "one ton". Sometimes, stupid units can be helpful, because "one ton" of cooling is what you get if you dump one ton of ice (short ton, of course) per day in the place. So you'd need a lot of ice, many tons per station, to make a significant difference.
Either way, since this is such an obvious idea, and they had a competition to solicit solutions, I'm sure this was evaluated and discarded - although it would be interesting to read the official analysis of the idea and learn why it wouldn't work.
Where there’s space, this has already been done. Unfortunately for many lines there simply isn’t space.
Just about every abandoned station, elevator shaft, and maintenance tunnel on the network is already fitted out with huge fans where possible.
TfL also runs a semi-continuous works project that looks a custom and novel one-off cooling solutions that can be retrofitted into whatever space is left. Including complicated hydronic systems that pump around huge quantities of water where the infrastructure allows for it.
> Historically, the Underground infrastructure offered a respite from warm weather, indicated in Austin Cooper’s ‘It is cooler below’ poster, issued in 1924 by the Underground group to promote a more comfortable experience of travel during warm weather.
A century of burrowing commuter-worms unfortunately managed to bake all the beautiful wet clay that kept the tunnels tolerable when the sun was shining about.
It seems straightforward to me that it would be enough to rehydrate the ground. Just need (approximately),
400km of track * 25m average depth * 3m tunnel width * 20% moisture content of wet clay
= 6 billion litres of water
Sounds like a lot but it's only about 1/300th of the yearly flow of the Thames.
I don’t think the hydration of the clay is the important element here. Rather I suspect it’s simple just the sheer mass of clay, wet or otherwise, that’s involved.
There’s a reason why ground source heat pumps work so well. It’s because the ground is such a fantastically huge heat sink/source that in most scenarios we consider it capable of sinking or sourcing a practically unlimited amount of heat.
Unfortunately one of the scenarios where this breaks down, is when you stick a bunch of tunnels in the ground, then pump a crap ton of energy into those tunnels years round, and expect the ground to sink all the heat away. Turns out, if you do that, the ground itself starts heating up, and given that clay is a reasonable good insulator, it’s like wrapping all those tunnels in wool jumpers.
I would point out as well that all these tunnels are “deep level” tunnels running at an average depth of 24 meters and getting as low as 67 meters. The heat of the sun on the ground surface will have approximately zero impact on the tunnel temperatures. 24 meters of clay is a lot of insulation to work with.
My original comment was meant to be tounge-in-cheek, but I would like to add the advantage of wet clay is really in its thermal conductivity[0] which is roughly two to four times higher than dry clay. It will also have higher thermal capacity, so that high frequency fluctuations (like day/night) will be smoothed out.
(I don't think my comment implied that the sunshine makes it hot in the tunnel, only that when it's hot above ground it's nice to be cool below, like in the poster. And I did include a figure of 25m for average depth, I've spent enough time on their endless stairs to know that the TfL delved to greedily and too deep. This spiral staircase has 320 steps, I shudder.)
I think you are right. The graph at the bottom of the article shows that temperatures dropped around 2020 (presumably less traffic due to the pandemic).
So the ground can take up more heat, but it can't do it quickly enough.
<man walks into sauna room> Ooh, it's a bit hot in here! I better throw some water on these rocks to cool them down.
Joking aside, I actually don't know how dry it is in the underground, and therefore whether adding water for evaporative cooling would work. I would have assumed it was quite humid, but maybe not?
It would be if they tried cooling it with water, for sure; evaporative cooling would only work if there's enough airflow, else they'd just get 100% humidity so it would be both hot and humid.
It seems implausible to me that the clay is dehydrated. The Victoria line was only built in the 60s and has a waterproof lining. (It's also built with asbestos cement, unfortunately, which is no doubt a problem when they need to cut it for whatever reason)
The cement can negatively effect the water retenction of the clay, as does of course the temperature. The water needn't seep into the tunnel, just be moved away from it to adjacted areas.
As I see it, it is just a marketing problem with easy solutions.
There is psychology and reverse psychology. You could fool people into embracing the heat by redecorating the stations and trains to make it a 'journey to hell, via the centre of the earth'. The stops south of the river could be marketed as Dante's inferno and hellish.
Or you could go the other way, to make it kitch Hawaiian themed, so people expect the heat and to embrace it as a mini-holiday.
Or, the stations could be redecorated as if it were a trip to the Antarctic, so people see images of penguins braving the ice, with murals from the Shackleton days, to imagine they are cold.
In places like Moscow the underground train stations give the impression that people are in splendid palaces, this works pretty well. As I see it, TfL just need to up their decor game, problem solved.
Unfortunately, hydrating clay is extremely hard to do. Clay is what you use as a water-tight material in dams, artificial lakes, waste dumps and stuff like that, because water doesn't really pass through it.
It was just a bit of a shower thought to be honest, but it looks like there are cleverer and more responsible people who've considered similar schemes.
Isn't heat free energy in a place like London? I know very little about metro systems so please correct me if this is insane: wouldn't the people living above the tubes be happy to get a heat exchanger (passive) or heat pump (active, but takes more of the heat) that prewarms their hot water supply? People still take warm showers and boil tea and rice/pasta in summer, and in winter the purpose should be obvious. If the water comes in at 30 instead of 10 degrees C, you need to add only a few degrees for showers and floor heating
A problem is the clay surrounding the tunnels insulates them - it traps heat because heat flows through it very slowly. So you drill down and put a heat exchanger pipe down there, you pump heat from 3cm of clay around the pipe and now no heat flows through the clay to your pipe even though there’s a lot of heat still down there.
Your pipe becomes a tiny worm of cold pipe in a big lump of hot clay and you’ve done very little to cool the underground or warm your water. That is, if heat moved easily through the stuff then the problem of heat buildup would be easy to solve but in that case heat wouldn't build up so there wouldn't be a problem; and vice-versa.
Yes but the only places we care about extracting heat are the tunnels, so you'd just run pipes through the tunnels themselves to extract heat. I think the bigger issue is the amount of energy needed to get the water down there and back up just means it doesn't make much sense on its own.
Your are correct in principal, though implimenting your idea, now, is essentialy impossible as installing the plumbing after the fact might cost more than just starting over with a whole new line, and would in fact make things much worse durring the many years it takes to find out if the
added systems even work.
Given that there is only clay under London, it is by far better to start over and build a whole new line, and/or go all in on a mega high tech ,high pressure refrigeration systems for the human occupancy areas, and hope that there are no break downs in the "hot zones"
orrible mess
Heat is to energy as feces to food. It's not quite valueless by mass or by volume, but close enough that for most purposes the major issue is rejection.
Nice analogy, in hindsight only it’s in the name: waste heat. It takes the tiniest bit of impolite thoughts to make that lovely connection, thanks for that morning coffee bit of trivia.
>wouldn't the people living above the tubes be happy to get a heat exchanger (passive) or heat pump (active, but takes more of the heat) that prewarms their hot water supply
Ground source heat pumps are expensive to build, even more so in a dense area like London. So even if everything you said is true, I suspect the juice isn't worth the squeeze.
In this case, though, the excess heat is a major burden, so there is room to negotiate with a district thermal provider that pays that provider to absorb and redistribute the heat, as long as it's less than the cost to pump it out to the environment.
I'm not saying it's easy (it will likely be a bespoke solution). Given the organizations, I expect the difficulty to be as much business (setting the prices) and political (defending the prices set) as technical.
There is at least one on this line (north of Kings Cross) and one on the Northern line (north of Moorgate). It's for district heating or electricity generation.
The entire issue is that the earth surrounding the tubes is acting as a giant buffer. Enough heat has been dumped into it over the years that it has permanently warmed up. Draw heat from it during the winter to warm up homes, and it'll be able to absorb more heat from the tunnel air during the summer.
It won't be zero so spreading it across enough people might already solve it. If that still leads to insufficient demand during the hottest weeks, idk, it's energy, surely there's something useful you can do? Store it for next week, pre-heat water for the nearest steam engine (e.g. gas power plants are steam engines running on methane, so if they have to heat the water by fewer degrees.. The problem will be finding a steam engine close to the heat source), supply it to an industrial process that needs temperatures above ambient (egg breeding for vaccine production? Idk), create electricity from the temperature differential between this system and the Thames water using the Peltier effect
I've surely got a too naïve view of economics but if the goal were to not waste resources then there will be things you can do before dumping it into the hot summer air
Indeed, the Department for Transport was renamed in 1997, and TfL followed suit in 2000.
There is a minor fandom controversy over the Ministry of Magic in the Wizarding World and whether the "Ministry for Magic" and "Minister for Magic" are valid alternate terms, but I have only identified one instance where JK Rowling wrote it this way, and it was outside the novels. Canonically, Harry turned 17 in 1997, so I suppose Tony Blair's reforms wouldn't apply post-Voldemort. However, Platform 9¾ is now "properly labelled" in the Muggles' King's Cross Station.
Travellers should also mind the gap between "TfL" and "TLF Travel Alerts", a defunct account which was part of Weird Twitter, and somewhere I hope I can dig up an archive, because the daily alerts were comic genius in 140 characters or less.
The arrival of Paddington Bear from Darkest Peru may be partly explained by the heating of the Tube stations. He surely would be right at home in a dark, humid and warm environment. My mother encouraged me to read about Paddington Bear, and in 2008 I was privileged to have a layover in Westminster, where I passed through Paddington Station and totally missed out on visiting the Paddington Bear statue therein. But I was able to purchase a refrigerator magnet bearing the "MIND THE GAP" official logo, which I presented to her in gratitude.
Of a special tube train with blocks of ice. You’d need to have various pits dug in, and pumps to drain the water. Yes water and power electronics is “fraught”.
I just like the idea of trains trundling along, blocks of ice being carted out and gradually melting.
Another idea is to move mechs-bots via Underground in a post-apocalyptic scenario, but that’s not so relevant here.
Make tram cars that sit on giant plates that straddle giant cuboids of ice, and rail beds that are like luge lanes, pulled along by overhead ropes. Have the water in the lanes flow at the ends into waterwheels that help drive the ropes as a primitive form of energy recovery, all driven by a power-take-off from a giant coal power steam engine on the surface that also serves to power a massive reverse-rankine cycle refrigerator that makes the ice blocks and slides them down into the tunnels - the gravity also helping pull the ropes that drive the trams. Of course, the massive coal plants are going to accelerate global warming, so you're gonna need to build more of these ice-cooled underground transit systems and even water chilled underground housing for people as the surface temperatures rise and rise....
And now you've got this wild 19th century Jules Verne-esque icepunk world in thermal runaway all built up for a hell of a novel-to-be.
But then they'd spend more energy (and more braking) hauling that ice around; would the amount of heat absorbed be more than the one ice train would generate?
There's probably more efficient materials to use, big lumps of supercooled metal. Someone else mentioned liquid air, that could just be evaporated in the tunnels and stations.
Of course, generating liquid air costs a lot of energy too. I'm sure the problem is easily solved if you assume infinite and free energy.
> tunnel ventilation installations, chiller systems pumping chilled air into mid-tunnel shafts and regenerative braking to reduce heat generated by trains breaking
The hoops TfL jumps through just to not extend AC to the rolling stock in more lines are baffling. At least we finally got some AC in the new Piccadilly rolling stock.
I think AC net adds heat to the system, we just don't usually care because the hot end is outside. Here the hot end of an ac unit on the rolling stock would be in the same clay-insulated tube and not escape, so I think it would be a problem? They have to get the heat out of the underground and up to the surface somehow.
You can redesign the signalling systems etc to work at even 40C, plenty of countries do it. You can't redesign humans to feel comfortable inside a stuffy carriage at 35C.
> The Senior Press Officer added that with many stations in close succession, the Victoria and Central lines experience frequent acceleration and braking, contributing to heat buildup within the tunnels.
I'm sure that this is probably one of those stupid suggestions that shows a lack of understanding of the problem, but could skipping stations help help this? Something like the following gets you 1/3rd less braking energy released into the tunnels:
Taking a look at the peak time schedules they have trains coming every 2 minutes, so this seems like it would be reasonable for most people to have to sometimes wait 6 minutes for the right train, but generally not more than 4.
Probably not, because the limiting factor on train throughput is remaining a safe braking distance behind the train in front. If the train in front of you has stopped at station D then you need to stop in station C even if you don't open the doors.
(You could get around that by running the trains further apart, but that would be a critical loss of capacity).
With frequent trains and close stop spacing you've plausibly got a situation where each train is entering and leaving each station at about the same time? So skip-stop might not save much acceleration/braking.
I mean sure, less trains would help alleviate the problem (to simplify your proposal), but they still need to move all those people every day. Hence the 2020 reduction in heat increase, less people = less trains = less heat buildup.
Readit News
Conversely, the increase in the average annual temperatures across all Underground lines from 2013 to 2024 was merely *seven percent*, placing Victoria’s temperature rise vastly above that."
Using percentages to talk about changes in non-Kelvin temperatures is crazy.
28 degrees Celsius is not 30% warmer than 21 degrees Celsius. This same stat rendered in Fahrenheit would say 70 degrees -> 82 degrees, or 17%. In kelvin it would be 294 -> 301, or 2.3%
Or we could invent a new measure indexed to Celsius but offset by 20 degrees, and declare a 1 -> 8 change, a whopping 700%.
The trouble (of course) is that Celsius properly is not a proper unit, but a "scale", or a "unit of difference" (equal to kelvin), or even torsor[1].
The trouble with the kelvin here is that if you see the 7 kelvin increase as a proportion of the 295K starting temperature the you only get a 2% increase. Nobody is going to buy your newspaper if you're putting up weak numbers like that.
[0] https://mathematicalcrap.com/2024/03/05/the-feynman-story/ [1] https://math.ucr.edu/home/baez/torsors.html
Edit: this comment was deeply stupid for obvious reasons and I regret trying to interact with other people when I should be asleep.
== The Victoria Line average temperature in August last year was 60% higher in temperature than the average external temperature that month, measured at 19.5 degrees. ==
Certainly for January it must have been hundreds of percent higher.
And what would the numbers be for e.g., the Moscow metro in winter months where the average outside temperature is negative?
I apologise.
This is done when people rate the efficiency of home heating: SCOP is a function of the heat pump's ability to hit a particular temperature, for instance.
I'd guess the baseline temperature on the tube should be 21C maximum. Percentages don't make sense here, but 7C over the target temperature (for instance) is pretty bad in those terms. I'd be surprised if TfL hadn't set that somewhere.
Also worthy of note is that it sounds like the tube is a prime source of heat for a district heating system. Win win, perhaps.
If you go from freezing water to boiling, it's only 37% hotter!
It’s a huge increase, if not for the reasons they describe.
Everyone knows where the zero is in Celsius using countries anyway and days in the negative are so rare in the UK you can discount them (plus they are none inside the tube).
Moving more air through the tunnels, adding A/C systems - both have a problem of needing room up on the surface for blowers and compressors, something that is hard to do in modern London. Tough problem.
That said, a typical shitty single-hose monoblock air conditioner has 9000-12000 BTU/h of rated cooling capacity. 12000 BTU/h is also known as "one ton". Sometimes, stupid units can be helpful, because "one ton" of cooling is what you get if you dump one ton of ice (short ton, of course) per day in the place. So you'd need a lot of ice, many tons per station, to make a significant difference.
Either way, since this is such an obvious idea, and they had a competition to solicit solutions, I'm sure this was evaluated and discarded - although it would be interesting to read the official analysis of the idea and learn why it wouldn't work.
Just about every abandoned station, elevator shaft, and maintenance tunnel on the network is already fitted out with huge fans where possible.
TfL also runs a semi-continuous works project that looks a custom and novel one-off cooling solutions that can be retrofitted into whatever space is left. Including complicated hydronic systems that pump around huge quantities of water where the infrastructure allows for it.
A century of burrowing commuter-worms unfortunately managed to bake all the beautiful wet clay that kept the tunnels tolerable when the sun was shining about.
It seems straightforward to me that it would be enough to rehydrate the ground. Just need (approximately),
Sounds like a lot but it's only about 1/300th of the yearly flow of the Thames.There’s a reason why ground source heat pumps work so well. It’s because the ground is such a fantastically huge heat sink/source that in most scenarios we consider it capable of sinking or sourcing a practically unlimited amount of heat.
Unfortunately one of the scenarios where this breaks down, is when you stick a bunch of tunnels in the ground, then pump a crap ton of energy into those tunnels years round, and expect the ground to sink all the heat away. Turns out, if you do that, the ground itself starts heating up, and given that clay is a reasonable good insulator, it’s like wrapping all those tunnels in wool jumpers.
I would point out as well that all these tunnels are “deep level” tunnels running at an average depth of 24 meters and getting as low as 67 meters. The heat of the sun on the ground surface will have approximately zero impact on the tunnel temperatures. 24 meters of clay is a lot of insulation to work with.
[0] https://www.mdpi.com/2571-8789/8/2/47
(I don't think my comment implied that the sunshine makes it hot in the tunnel, only that when it's hot above ground it's nice to be cool below, like in the poster. And I did include a figure of 25m for average depth, I've spent enough time on their endless stairs to know that the TfL delved to greedily and too deep. This spiral staircase has 320 steps, I shudder.)
So the ground can take up more heat, but it can't do it quickly enough.
Joking aside, I actually don't know how dry it is in the underground, and therefore whether adding water for evaporative cooling would work. I would have assumed it was quite humid, but maybe not?
There's a nice article here which goes into more detail: https://www.ianvisits.co.uk/articles/cooling-the-london-unde...
I think Oxford Circus is one.
As I see it, it is just a marketing problem with easy solutions.
There is psychology and reverse psychology. You could fool people into embracing the heat by redecorating the stations and trains to make it a 'journey to hell, via the centre of the earth'. The stops south of the river could be marketed as Dante's inferno and hellish.
Or you could go the other way, to make it kitch Hawaiian themed, so people expect the heat and to embrace it as a mini-holiday.
Or, the stations could be redecorated as if it were a trip to the Antarctic, so people see images of penguins braving the ice, with murals from the Shackleton days, to imagine they are cold.
In places like Moscow the underground train stations give the impression that people are in splendid palaces, this works pretty well. As I see it, TfL just need to up their decor game, problem solved.
As I posted in a cousin comment, I found this nice blog post examining some of the more serious ideas, including water-cooling: https://www.ianvisits.co.uk/articles/cooling-the-london-unde...
Your pipe becomes a tiny worm of cold pipe in a big lump of hot clay and you’ve done very little to cool the underground or warm your water. That is, if heat moved easily through the stuff then the problem of heat buildup would be easy to solve but in that case heat wouldn't build up so there wouldn't be a problem; and vice-versa.
Dead Comment
These are some of the deepest tunnels going under some of the most built up parts of the UK.
[0] https://en.wikipedia.org/wiki/Windcatcher
Ground source heat pumps are expensive to build, even more so in a dense area like London. So even if everything you said is true, I suspect the juice isn't worth the squeeze.
In this case, though, the excess heat is a major burden, so there is room to negotiate with a district thermal provider that pays that provider to absorb and redistribute the heat, as long as it's less than the cost to pump it out to the environment.
I'm not saying it's easy (it will likely be a bespoke solution). Given the organizations, I expect the difficulty to be as much business (setting the prices) and political (defending the prices set) as technical.
The entire issue is that the earth surrounding the tubes is acting as a giant buffer. Enough heat has been dumped into it over the years that it has permanently warmed up. Draw heat from it during the winter to warm up homes, and it'll be able to absorb more heat from the tunnel air during the summer.
I've surely got a too naïve view of economics but if the goal were to not waste resources then there will be things you can do before dumping it into the hot summer air
https://tfl.gov.uk/
https://en.wikipedia.org/wiki/Transport_for_London
There is a minor fandom controversy over the Ministry of Magic in the Wizarding World and whether the "Ministry for Magic" and "Minister for Magic" are valid alternate terms, but I have only identified one instance where JK Rowling wrote it this way, and it was outside the novels. Canonically, Harry turned 17 in 1997, so I suppose Tony Blair's reforms wouldn't apply post-Voldemort. However, Platform 9¾ is now "properly labelled" in the Muggles' King's Cross Station.
https://commons.wikimedia.org/wiki/File:Cmglee_London_Kings_...
Travellers should also mind the gap between "TfL" and "TLF Travel Alerts", a defunct account which was part of Weird Twitter, and somewhere I hope I can dig up an archive, because the daily alerts were comic genius in 140 characters or less.
https://commons.wikimedia.org/wiki/File:Paddington_Bear_Stat...
The arrival of Paddington Bear from Darkest Peru may be partly explained by the heating of the Tube stations. He surely would be right at home in a dark, humid and warm environment. My mother encouraged me to read about Paddington Bear, and in 2008 I was privileged to have a layover in Westminster, where I passed through Paddington Station and totally missed out on visiting the Paddington Bear statue therein. But I was able to purchase a refrigerator magnet bearing the "MIND THE GAP" official logo, which I presented to her in gratitude.
Deleted Comment
Of a special tube train with blocks of ice. You’d need to have various pits dug in, and pumps to drain the water. Yes water and power electronics is “fraught”.
I just like the idea of trains trundling along, blocks of ice being carted out and gradually melting.
Another idea is to move mechs-bots via Underground in a post-apocalyptic scenario, but that’s not so relevant here.
And now you've got this wild 19th century Jules Verne-esque icepunk world in thermal runaway all built up for a hell of a novel-to-be.
There's probably more efficient materials to use, big lumps of supercooled metal. Someone else mentioned liquid air, that could just be evaporated in the tunnels and stations.
Of course, generating liquid air costs a lot of energy too. I'm sure the problem is easily solved if you assume infinite and free energy.
Besides at that temperature, more water can be absorbed in the air, so not just latent heat of melting, but heat absorbed in evaporation too.
Of course that would have to be wafted out, and not pumped were it just water.
The hoops TfL jumps through just to not extend AC to the rolling stock in more lines are baffling. At least we finally got some AC in the new Piccadilly rolling stock.
Deleted Comment
Deleted Comment
I'm sure that this is probably one of those stupid suggestions that shows a lack of understanding of the problem, but could skipping stations help help this? Something like the following gets you 1/3rd less braking energy released into the tunnels:
Taking a look at the peak time schedules they have trains coming every 2 minutes, so this seems like it would be reasonable for most people to have to sometimes wait 6 minutes for the right train, but generally not more than 4.(You could get around that by running the trains further apart, but that would be a critical loss of capacity).
https://en.wikipedia.org/wiki/Skip-stop