Roasting Bakerloo

[Tubeboy]

Why is the Bakerloo so hot?

Its the hottest line [personally speaking]

Went to Oxford Circus today, Northern to Euston, then the Victoria. Went to staff travel, back down, but to the Bakerloo, the heat was awful on the platform. The train was like an oven, Many people looked uncomfortable, myself included, I felt clammy.

Why is it so hot? The Piccadilly and Northern were built at the same time, but are nowhere near as hot. Explanations please, but, dont be too technical please!

[Deleted]

Felt lovely and cool today on the SSLs - and also the Central felt cool.
Not that that's any help to the question

[Oracle]

The Bake-a-loo used to be hot and peculiarly smelly when 1938 Tube Stock was running! One stupid thought...unlike the Northern and Piccadilly there is only one end open to the air, so trains on those lines can act as pistons and push air through in theory from one end to the other, affected by exits, etc. whereas the brown line has only one exit/entrance now...formerly two of course! Was the Vic built with better ventilation from new?

Of course people act as natural radiators of heat being exothermic, and large crowds can generate huge amounts of heat.

[CSLR]

tubeboy said:

The Piccadilly and Northern were built at the same time, but are nowhere near as hot. Explanations please, but, dont be too technical please!

Without being too technical; bits of the Northern were built at the same time. Other bits were earlier, while the bit down the bottom and the twiddly bit round Camden were a bit later.

[Tubeboy]

Yes I know mate, but they werent built MANY years apart.

[Tom]

If you think it's hot during the day, try being down there at 3am with no air movement!!

[CSLR]

tubeboy said:

Why is the Bakerloo so hot?

Back in the days when the circulation of air on the tube system was a less important issue, the railways promoted the fact that they were 'cooler in summer, warmer in winter'.
Has it occurred to anyone to apply a degree of lateral thinking and ask if the current unbearable heat might be linked to heatwave-warmed-air being sucked in by the larger number of ventilation fans?

[agoodcuppa]

cslr said:

Has it occurred to anyone to apply a degree of lateral thinking and ask if the current unbearable heat might be linked to heatwave-warmed-air being sucked in by the larger number of ventilation fans?

I'm inclined to agree with your main argument, but on a point of detail I was always under the impression that air comes into the tunnels through the stations and is expelled through the fans and ventilation shafts.

So perhaps a means of cooling the air as it flows into the stations is what's needed?

[CSLR]

agoodcuppa said:

I'm inclined to agree with your main argument, but on a point of detail I was always under the impression that air comes into the tunnels through the stations and is expelled through the fans and ventilation shafts.
So perhaps a means of cooling the air as it flows into the stations is what's needed?

Absolutely, The air is sucked out of the tunnels which means that, during hot weather, warm air is entering at the stations to replace it (the suction effect of the fans is therefore inducing the inflow). That in turn warms the platforms, creating the opposite effect to what is required temperature wise.

[agoodcuppa]

OK, so the solution is easy.

Install stonking great fridge/air-con units at each tube section station and cool the air entering the station.

But, the heat being extracted has to go somewhere and the only place available is the atmosphere. (Put your hand over the gap between the back of your domestic fridge or freezer and feel the amount of heat coming off that!)

Aren't we simply creating yet another vicious circle?

[CSLR]

agoodcuppa said:

OK, so the solution is easy.
Install stonking great fridge/air-con units at each tube section station and cool the air entering the station.
But, the heat being extracted has to go somewhere and the only place available is the atmosphere.

Actually, that is not the only place that it has to go. The subject of using refrigeration type systems and possible uses for the warm air (other than expelling it to atmosphere) was recently discussed in this thread
districtdave.proboards39.com/index.cgi?action=display&board=general&thread=1153763696&page=1
This though is just one possible solution, there are many more.

[Deleted]

I actually think the hottest part of the tube network is the Victoria Line! Just from sheer number of crowds and hence body heat, especially between Kings Cross and Victoria. I've never known a hotter environment elsewhere on the network...

[Deleted]

Rheostatic braking probably doesn't help with the heat either.

[Deleted]

stephenk said:

Rheostatic braking probably doesn't help with the heat either.

For the third time, it doesn't matter whether braking is rheostatic or friction: it's the same amount of kinetic energy converted to heat!!

[Deleted]

sydneynick said:

stephenk said:

Rheostatic braking probably doesn't help with the heat either.

For the third time, it doesn't matter whether braking is rheostatic or friction: it's the same amount of kinetic energy converted to heat!!

You forgot about the regenerative braking option, which modern tube trains have.

[Deleted]

You also need a power supply that does not object to the trains trying to feed electricity back. The Metadyne equipment on the 1936 O and P surface stock was, in theory, capable of regenerative braking but it caused all sorts of problems in the electricity supply substations.

How recently have the Underground substations had new equipment?

[bobbybrakedust]

can we not simply spin the massive extractor fans the other way round and make them suck air in and cool it by speeding it up like a conventional fan ??
then the stations would act like a massive exhaust instead of an oven?

[Phil]

Sorry: as to the last, if you speed up a fan you actually WARM the air up!! (It feels cooler simply because the air is moving).

[CSLR]

bobbybrakedust said:

can we not simply spin the massive extractor fans the other way round and make them suck air in and cool it by speeding it up like a conventional fan ??
then the stations would act like a massive exhaust instead of an oven?

It is not quite as simple as that. The ventilation system has been designed and balanced to work in the direction that it does; reverse it and you will need to make a lot of changes.
Another problem is that the current system generally allows stale dirty air to be expelled in convenient non-public areas, and fresh air (about as fresh as you will get in London) to enter via the stations. The last thing that is needed is passengers being met at stations by an egress of stale dirty air that is being blown out of the tunnels.
It might be possible to modify the system so that larger quantities of cooler air could be sucked into the tunnels at night, but it is questionable how effective the result would be throughout the day.

[bobbybrakedust]

how long would it really be a problem for though, if we were to get the tunnel cleaning train out daily until the state of the tunnels was better and the fans were reversed
surly you could just turn the blade upside down or summit
the stale air would be a prob initially but surely the problem would get better over time

[agoodcuppa]

bobbybrakedust said:

can we not simply spin the massive extractor fans the other way round and make them suck air in and cool it by speeding it up like a conventional fan ??
then the stations would act like a massive exhaust instead of an oven?

That was how things were arranged originally but it was found that the air being forced into the vent shaft by approaching trains caused the fans to attempt to reverse direction so the engineers "went with the flow".

[Oracle]

Metadayne systems were also fitted to Battery Locos.

[greatplum]

I've always thought the Victoria was the hottest line. (I take both the Vic and the Lakerboo every day to work!)

[Tubeboy]

Bakerloo is the hottest, then the Victoria. Thats me personally anyway.

[greatplum]

Actually they are both stifling!

OK this week though!

[alstom1996]

I always find that Warren Street is a very warm stuffy station, as soon as you enter the station you can feel it.

[Tubeboy]

Lambeth North is very hot. The coke machine must do a roaring trade, particularly in the summer

[version3point1]

tubeboy said:

Lambeth North is very hot. The coke machine must do a roaring trade, particularly in the summer

That's if it hasn't broken down beacuse of the heat.

[Tubeboy]

I have used it a couple of times, the coke has always been cold. No doubt it is pumping out hot air making the platforms even hotter!