I don’t know if you’ve been to london, but if you’re a standard “modern” height for a man you can barely to not even stand straight in the deep tube trains. They are very very small, and limited by the tunnels which are absolutely tiny. I’m not surprised fitting air conditioning is a challenge, even ignoring the ventilation issues which are also massive.
Yep, same as many other things we take for granted in modern constructions, such as accessibility, good signage, enough space on stations and tunnels for easy flow of passengers, platform screen doors, etc.
It's a no brainer when building today, but wasn't back then, and retrofitting is extremely complex and expensive.
The entire network is a single line which circles the city, the map shows 2 lines, one clockwise, one anticlockwise. The trains have a dirty orange livery, hence the local name: The Clockwork Orange.
It's a huge achievement considering both the technical challenges (which other comments explain) but also that anything actually got done considering the UK's economic and political disaster.
Well fortunately New Tube for London (this new train design) all got signed-off a decade ago. Buuuuuut, TFL only bought the trains necessary for the Piccadilly line, with "options" to buy trains later for the other lines. However, post-Covid they don't have enough money to buy them anymore, and would need the government to pay for them, which it likely won't. So I won't be holding my breath for any further improvements :-(
I don't think it's a myth. The UK is actually two economies. It's basically southern Italy with NYC bolted onto it. The average numbers like those you've posted include London and look basically OK, but the London effect is hiding a lot.
Take out London and the rest of the UK is an economic basket case with low education levels, high rents, rapidly aging citizens, low wages, low investment, low productivity, a small tax base and a public estate in poor condition.
This was a really interesting piece on the matter, in fact most of Murdoch's work for the FT is excellent
London itself is very divided. There's plenty of money in a few select areas, but wastelands of poverty around them.
The UK has a huge reservoir of natural talent which it's doing its best to destroy. Plastic populism suits the ruling class much better than invention and originality.
> There's plenty of money in a few select areas, but wastelands of poverty around them
You can find the wealth and the poverty very close by, even at the same London address. i.e. a flats with huge book value, privately owned; and rented out to struggling people who will never be able to afford to buy their own flat.
> It's basically southern Italy with NYC bolted onto it.
More like "basically Romania with Vlad Tepes bolted onto it". The London-driven finance-first economy (to which I partake, btw) inevitably sucks the blood out of the rest of the country.
Here in Hamburg the S-Bahns are only just being replaced by air conditioned models. I don't think there are even plans for an air conditioned U-Bahn yet
Where would the waste heat go? Air Conditioning units dump the heat "outside" into the air. But there is no "outside" in deep tunnels. Worse, Air Con has to work to move heat, which creates more heat. You can't even break even. See the 2nd law of Thermodynamics.(1)
It's not so much "air con on trains" but "air con in deep tunnels without a vent". There is nowhere for the heat to go, and the tunnels have already warned up over the decades. (2)
> Conventional air conditioning was initially ruled out on the deep lines because of the lack of space for equipment on trains and the problems of dispersing the waste heat these would generate.
Every solution is a costly compromise. e.g. drilling a new vent to the surface is theoretically possible, but very hard in a densely populated and built-up area.
A lot of comments talk about tunnel size, which is a minor factor: Everything's easier to engineer when you have more space. But fundamentally the issue is where to send the waste heat, not "tunnel too small".
Air conditioning in a busy 19th century underground tunnel system is absolutely an achievement.
Air conditioning an underground train means pumping that hot air into the tunnels. The tunnels have insufficient ventilation because this wasn't conceived of as a problem when many of them were built, and that's a challenge to rectify.
There's also the issue that the trains are already making the tunnels too hot. 4000 trains running back and forth generates a lot of heat from both the engines and braking friction. That heat goes into the clay of the tunnel and is very slow to dissipate due to the high heat capacity of the clay. The trains are never stopped for long enough for the temperature to drop, and so the temperature of the clay has slowly risen 5-12 degrees depending on the line from when the first line was dug in 1863.
Air conditioning the carriages of the new trains didn't result from any developments in air conditioning technology, but from breakthroughs reducing the thermal output of the engines and brakes. This gives them a heat "budget" letting them air condition the carriages without outputting any more heat into the tunnels than a standard train.
Yes, given the size constraints of the deep-level Tube tunnels, which are much smaller than those for mainline trains; apparently developments in small air con systems have helped a fair bit here, fifteen odd years ago apparently it just wasn’t feasible.
Arguable the more fundamental problem is this. Air-con is a negative-sum game because it not 100% efficient. As well as moving heat from one place to another, it creates extra heat.
Turn air-con on in an enclosed space, with nowhere to vent the exhaust, and that space just gets hotter. A small, deep tunnel is close to being an enclosed space. You might be able cool the train interior a bit, but the tunnel will get hotter. Meaning the air-con has to work harder. Meaning it generates more heat.
The Picadilly line is already uncomfortably hot for a good part of the year (but far from the worst [1]). This includes the platforms.
What this article says is that the trains themselves are lighter and more efficient, so less heat is generated by the motors and brakes. They argue that that gives them some heat budget to use on air-conditioning. As a whole, the new trains will generate roughly the same amount of heat as the old ones. So the tunnels and platforms will stay around the same (ie, too hot!), but the train interior will be comfortable.
Adding AC units to trains which travel through tunnels with minimal clearance is the achievement - Can't make the trains any bigger and there's no room in the old ones to just tuck an HVAC in without make them even more cramped.
Headroom is not an issue - there is plenty of room underneath the trains between the wheels. They then pump the cooled air up through the walls to where they want vents. Sometimes trains use the space between the wheels for passengers, but that has significant disadvantages and so should be avoided for subways (it is worth it for street running trams!),
It is here; they're small trains and the tunnels are very warm already, so the AC isn't as efficient, and adding more heat to the tunnels (which all comes from the running trains) will make it more inhospitable.
There are some projects underway to try and cool the tunnels, but they're deep underground and have accumulated heat over decades.
The challenge here is specific to this line - other lines (like Circle) already have AC on the trains - mainly because they’re absolutely huge trains by comparison
London 2 main types of underground line: Subsurface (Circle, District, Metropolitan and Hammersmith and City lines), and tube. The subsurface lines were constructed by cut and cover and were made for steam engines. They are much larger than the tube lines. The Tube lines are tunnelled, and designed for electric power only.
It's not really the size of the trains that allows AC on the subsurface lines, it the fact that the lines are well ventilated to allow steam and smoke from steam engines to escape.
Even the article specifically points out the size of the train as an issue
> To fit air conditioning into the trains has been rather an interesting challenge, as air conditioning units are large and tube trains are small, and Siemens Mobility has taken several ideas and put them together to create the space needed.
Of all the things TFL could do to improve the tube, cell service would not even be close to top of my list. We've had WiFi on the platforms for about 10 years which is enough to send/receive whatsapp messages while the train is stopped.
I'm not sure it's fair to dig out TFL for being backwards. They introduced the Oyster in 2003, something NYC didn't get until 2019.
That Wi-Fi is unusable. Not only does the association & DHCP negotiation take a large part of the time the train spends stopped at the station, but there's a stupid captive portal that also wastes whatever valuable time & bandwidth you manage to get despite the other issues.
I've been travelling to places where conventional mobile service is available in the subway and it's such an improvement. Being able to look at maps, message or browse the net is a godsend especially as a tourist in a foreign country.
Reliable comms everywhere allows fully centralized train control, with no employees on each train. You can use cameras to check no passengers are stuck in doors, on the track, or fighting in the carriages or platforms.
Now you can redeploy the staff away from repetitive tasks of driving trains and supervising stations, and towards engineering a better service. Get the typical journey speed up from 12 mph up to 45 mph. Make one direction of all tracks an express route that only stops at one station in 10 and drives 60 mph through all the others. Modify the old tunnels with an extra rail on a wall or ceiling for places where the tunnel alignment can't do 60 mph.
Are you a railway engineer or in some other related field?
Some of these suggestions sound a bit bizarre to a layman, especially considering your idea that the only thing standing in our way is 4G signal and reshuffling some staff.
> Get the typical journey speed up from 12 mph up to 45 mph.
So instead of 30 minutes from Walthamstow to Brixton it'll be 8 minutes? How is that possible?
There are 16 stations, or 14 stops excluding the terminii. If you stop for 30secs at each, that's 7 minutes in itself.
> Make one direction of all tracks an express route that only stops at one station in 10 and drives 60 mph through all the others
So we would have an express lane in one direction and a stopping lane in the other? Why is that a good thing?
To me an express service seems /slower/ than the status quo, because I would have to wait longer for the train that stops where I want it to.
> So instead of 30 minutes from Walthamstow to Brixton it'll be 8 minutes? How is that possible?
> There are 16 stations, or 14 stops excluding the terminii. If you stop for 30secs at each, that's 7 minutes in itself.
Or... you could stop at only 6 of the stops (express service). You could stop for 15 seconds door-open-time (as long as the crowd waiting for the train entirely fits on the train, thats very achievable - and crowd control can be managed by controlling platform ingress). Busses often achieve 3 seconds of door open time for comparison.
At a top speed of 60 mph, max acceleration of 0.2g, max jerk of 3 m/s^3 and travel distance of 2 miles per stop, the whole travel time becomes 13 minutes. Plus the 1.5 minutes for stops. =14.5 mins = 49 mph.
Lets schedule in one 30 second slowdown (ie. drunk guy holds door for mate for 30 seconds), and the average speed hits the 45 mph target.
I suspect the victoria line, being more modern in its track alignment, could easily be made to go 100 mph too...
How do the express trains get around the slower stopping trains? Or are you going to entirely remove two thirds of the stops?! I don't think you'll have any risk of crowded platforms, it'll be far too useless a service to attract many passengers.
You cannot compare bus stopping times with tube stopping times. It's meaningless. But if you must, the average dwell time for a London bus is closer to 15 seconds. Which is actually quite remarkable when you consider you've got to pay as you get on. And there's often a buggy or two trying to negotiate the driver having parked too far from the curb. The peak and off-peak must be wildly different and make this single measurement pretty useless.
Ok, so your big plan for quadrupling the speed of the tube is for trains to breeze through most stations without stopping. It's like amputation as a weight-loss tactic.
> So we would have an express lane in one direction and a stopping lane in the other? Why is that a good thing?
Simulate it and see...
Turns out that despite most users needing to make more changes, they will complete their journey far faster. The few journeys that are not completed faster (eg. taking the tube one stop) tend to either be walking distance or have an equivalent bus.
Combine it with the fact there are multiple routes from A to B and there are many people who can take the fast train in both directions.
For the railway operator, the trains are a big capital and operational cost. If you can make the trains run faster, you can get better utilisation of the seats, and therefore extra capacity/revenue. That more than outweighs the extra maintenance and electricity costs of going faster.