Why is the Central line so hot? Science has the answer

[holborncentral]

http://www.wired.co.uk/article/central-line-temperature-london-weather-heatwave

Cooling the Central line in particular presents an almost impossible puzzle for TfL to solve. In the late 1800s and early 1900s, when many of London’s tube tunnels were carved out of its subterranean clay, engineers didn’t leave a lot of extra space. In fact, they left none. That makes installing air-con units on trains that run through deep level tunnels impossible. The tunnels are too small to allow the heat to escape, effectively turning the Tube into a giant underground oven

[..]

Unlike the Victoria and Jubilee lines, London’s oldest tube lines, and the Central line in particular, suffer from having very few ventilation shafts...

It amazes me how the Central line is such a sauna of a line. Surely it can't be legal to transport passengers in those conditions? It's madness that we have to wait another 10 years for the new trains with air conditioning. IMO the Central should get them first and then the Piccadilly.

 

[Mutant Lemming]

I thought the highest temperatures were recorded on the Bakerloo - with it not being a 'through' tunnel (i.e. Elephant & Castle sidings being a dead end) it is less ventilated.

http://www.cityam.com/266954/official-ranking-hottest-tube-lines-according-transport

Surprisingly to City workers forced to endure the Central and Northern Lines every day, the Bakerloo Line takes the crown, with an average August temperature of 31.04 degrees centigrade.

That's followed by the Central Line...

Mosquitos used to breed down the sidings at E & C

 

[holborncentral]

I read that the other day but judging by what I saw on Twitter during the week people were all moaning about the heat on the Central and comparing it to a sauna Someone told me the other week not to go on the Central line in the summer because of the heat!

 

[Mutant Lemming]

I read that the other day but judging by what I saw on Twitter during the week people were all moaning about the heat on the Central and comparing it to a sauna Someone told me the other week not to go on the Central line in the summer because of the heat!

people always love to moan though - if they looked at it more positively then they are taking advantage of a free sauna

 

[Dstock7080]

It's madness that we have to wait another 10 years for the new trains with air conditioning. IMO the Central should get them first and then the Piccadilly.

Central Line 1992 Stock are almost 20years newer than the Piccadilly Line trains and about to receive a major upgrade; with new AC motors; LED lighting; improved Customer Information System, both audio and visual.

 

[holborncentral]

people always love to moan though - if they looked at it more positively then they are taking advantage of a free sauna

I tweeted something like that the other day why pay to have a sauna when you can just go on the Central line instead - it's cheaper!

 

[jellybaby]

taking advantage of a free sauna

It's inclusive, not free, damn it!

Unless you have a Freedom pass or something.

 

[Mutant Lemming]

It's inclusive, not free, damn it!

Unless you have a Freedom pass or something.

… the 'or something' in my case

 

[Clip]

http://www.wired.co.uk/article/central-line-temperature-london-weather-heatwave

It amazes me how the Central line is such a sauna of a line. Surely it can't be legal to transport passengers in those conditions? It's madness that we have to wait another 10 years for the new trains with air conditioning. IMO the Central should get them first and then the Piccadilly.

Well you only have to wait till next year for crossrail which is basically the relief central line so thats good eh?

 

[holborncentral]

Well you only have to wait till next year for crossrail which is basically the relief central line so thats good eh?

Is it really? I don't think it was meant to be a relief for any tube line. Crossrail is after all a completely different service, not another tube line.

 

[randyrippley]

http://www.wired.co.uk/article/central-line-temperature-london-weather-heatwave

It amazes me how the Central line is such a sauna of a line. Surely it can't be legal to transport passengers in those conditions? It's madness that we have to wait another 10 years for the new trains with air conditioning. IMO the Central should get them first and then the Piccadilly.

Air conditioned trains in a tunnel?
Just where do you think the heat is going to get dumped? You need to cool the tunnels, not the trains

 

[Dstock7080]

Air conditioned trains in a tunnel?
Just where do you think the heat is going to get dumped? You need to cool the tunnels, not the trains

A problem that LU and Siemens have solved:
https://tfl.gov.uk/info-for/media/p...d-manufacture-a-new-generation-of-tube-trains

Each new train will be six metres longer than the existing Piccadilly line trains. They will include walk-through, fully air conditioned carriages and improved accessibility, and will be specially designed to optimise the space constraints in the narrow Deep Tube tunnels.

 

[jellybaby]

Is it really? I don't think it was meant to be a relief for any tube line. Crossrail is after all a completely different service, not another tube line.

http://www.crossrail.co.uk/news/articles/crossrail-given-green-light-by-parliament
CROSSRAIL GIVEN GREEN LIGHT BY PARLIAMENT
Wednesday 23rd July 2008
...
When complete, there will be 24 trains per hour in each direction through Central London during peak times. This will provide substantial new passenger capacity and crowding relief, particularly on the Central and Piccadilly lines.

 

[Clip]

Is it really? I don't think it was meant to be a relief for any tube line. Crossrail is after all a completely different service, not another tube line.

Yes really.

 

[AM9]

Is it really? I don't think it was meant to be a relief for any tube line. Crossrail is after all a completely different service, not another tube line.

Just look at the map. Crossrail provides much relief to Central line traffic between Stratford and Ealing Broadway with specific interchange stops at Liverpool Street, Tottenham Court Road and Bond Street. It also provides relief for the major passenger flows on the Central line such as:

Giving much more space for those on the Central line who change at Mile End, Holborn, Notting Hill and Sheperds Bush
Bypassing the need to change onto the Circle/Met at Liverpool St (for KingsCrost/St P and Euston) by leapfrogging to Farringdon
Giving a quicker route (from the east or west) to Waterloo via TCR or Bond Street/Oxford Circus respectively
Even making St Pauls/Blackfriars more accessible by changing from the Lizzie to Thameslink at Farringdon​

Those new route opportunities couldn't be bettered even if the Central line was four-tracked.

 

[randyrippley]

A problem that LU and Siemens have solved:
https://tfl.gov.uk/info-for/media/p...d-manufacture-a-new-generation-of-tube-trains

Do you believe all press releases? These trains are still a paper exercise at present. When they come to get built the makers will be faced with simple physics: if you cool the trains, the tunnels will get hotter. And that heat will return each time the doors open, needing more work to remove it creating even more heat.....
Its an identical scenario to trying to cool a room by leaving the fridge door open

 

[Dstock7080]

Do you believe all press releases? These trains are still a paper exercise at present.

From a public body such as TfL, yes, especially when it’s a clear statement rather than the previous mentions of the ambiguous “air-cooling”.
I would think this is one of the priority specifications ordered by TfL.

 

[edwin_m]

Air conditioned trains in a tunnel?
Just where do you think the heat is going to get dumped? You need to cool the tunnels, not the trains

Do you believe all press releases? These trains are still a paper exercise at present. When they come to get built the makers will be faced with simple physics: if you cool the trains, the tunnels will get hotter. And that heat will return each time the doors open, needing more work to remove it creating even more heat.....
Its an identical scenario to trying to cool a room by leaving the fridge door open

The new trains will have regenerative braking, so around 20% of the traction energy which currently ends up as heat in the tunnels will be recovered instead. Even with some increases in train performance and frequency that ought to be enough to compensate for the extra heat put out by the cooling systems. There are also some projects to cool the Underground using things like groundwater and even heat pumps to nearby buildings.

It's interesting to read that when first opened the Tube tunnels were cool all the year round, and it has taken many decades for them to reach their current temperature.

 

[Mag_seven]

I wonder if the Central line trains are so hot in part due to the "glasshouse" heat they will gather on the above ground sections with those large windows?

 

[edwin_m]

Didn't the heavy tint on the windows get added sometime after they went into service, precisely because of this glasshouse effect? With hindsight a mirror effect would have been better, as the tint just converts the light to heat, some of which will radiate inside.

 

[Mikey C]

I'm sure more people are using the subsurface lines at the moment, due to their air conditioning, even on journeys when deep tube lines are more direct!

 

[Jimini]

I'm sure more people are using the subsurface lines at the moment, due to their air conditioning, even on journeys when deep tube lines are more direct!

I for one certainly am!

 

[Mag_seven]

Didn't the heavy tint on the windows get added sometime after they went into service, precisely because of this glasshouse effect? With hindsight a mirror effect would have been better, as the tint just converts the light to heat, some of which will radiate inside.

The tint seems to have minimal effect on the heat!

 

[Mikey C]

The tint seems to have minimal effect on the heat!

I'd HATE to have to commute in from Epping or West Ruislip on the Central Line, the 92 stock is like a greenhouse in the sun. It's notable that none of the subsequent stock has featured such large windows curving into the roof, and the new Siemens trains won't either from the artist impressions.

 

[Mutant Lemming]

I'd HATE to have to commute in from Epping or West Ruislip on the Central Line, the 92 stock is like a greenhouse in the sun. It's notable that none of the subsequent stock has featured such large windows curving into the roof, and the new Siemens trains won't either from the artist impressions.

Could be worse - say if there was works on the East end of the Central and your RRB was a new "Routemaster". In years to come when they are scrapped the top decks will make terrific greenhouses for growing oranges and other exotic plants

 

[Jimini]

I'd HATE to have to commute in from Epping or West Ruislip on the Central Line, the 92 stock is like a greenhouse in the sun. It's notable that none of the subsequent stock has featured such large windows curving into the roof, and the new Siemens trains won't either from the artist impressions.

*waves from South Woodford*

 

[RDWRER]

Are the Central line tunnels bored to a smaller diameter than the other deep tubes? The trains really do feel noticeably smaller. Or is it just the design of the stock itself?

 

[Dstock7080]

Are the Central line tunnels bored to a smaller diameter than the other deep tubes? The trains really do feel noticeably smaller. Or is it just the design of the stock itself?

The Central London Railway tunnels from Wood Lane-Liverpool Street were built to a slightly smaller diameter than has become standard; hence the rolling Stock must be fitted with high-lift positive shoe-gear. Rolling Stock is not any smaller on this Line.

 

[Mikey C]

Are the Central line tunnels bored to a smaller diameter than the other deep tubes? The trains really do feel noticeably smaller. Or is it just the design of the stock itself?

I'm pretty sure that all the deep tubes are the same, other than the Victoria Line which is slightly bigger, something which has been exploited with the 2009 stock, and much appreciated by myself when having to stand near the doors, the extra headroom is noticeable!

 

[holborncentral]

I'm pretty sure that all the deep tubes are the same, other than the Victoria Line which is slightly bigger, something which has been exploited with the 2009 stock, and much appreciated by myself when having to stand near the doors, the extra headroom is noticeable!

Weren't the Victoria line tunnels built to be able to accommodate mainline size trains?