Wed 25 Jun 2008
I read yesterday in the Metro that new cooling fans were being placed at a number of underground stations. Took them long enough! The article also stated that Mayor Boris was looking at ways of implementing Air conditioning onto the underground.Within the article it stated that there were issues getting air con onto underground trains. As cities such as Barcelona have air con on their metro line I wondered if someone knew what these issues were?
Posted by PC-Clene2 answers so far!
Okay, let's hear it.
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Are you referring to AC in the stations or on the subway cars?
In either case, it’s a matter of cost and efficiency. If you’ve already invested in subway cars without A/C and they’re servicing your population sufficiently, it’s quite a hassle to pull cars out of service and retro-fit A/C. And who knows if these old cars can even be retro-fit? You may just have to wait until cars live out their useful lives and then replace them with newer A/C-equipped models.
As for the stations, there are huge efficiency problems. Most stations that I’ve been to (in NYC and DC) have open-air entrances, which lets the cool air right out. And not to mention miles and miles of subway tunnels–you’ll be cooling them as well. To make matters worse, the subway cars (especially A/C-equipped cars) create a lot of heat.
Here’s an interesting blog post I came across:
http://subwayblogger.com/2007/07/09/lets-revisit-the-subway-air-conditioning-question/
Apparently, the subway system used to be cooler than street level. That had to do with an efficient ventilation system matched up with smaller trains and fewer riders. Now we have more riders and larger A/C-equipped trains and the same old ventilation system.
Anyway, it looks like the new second avenue subway line in NYC may get air-conditioned stations, but it will involve sealed off subway tunnels:
http://secondavenuesagas.com/2007/04/05/glass-walls-for-second-ave-subway-could-keep-passengers-air-trash-in/
The main problem with A/C on Underground trains is that there’s nowhere for the exhaust heat to go. Most of the deep tunnels are basically only big enough to hold the trains themselves, and there’s no system for venting heat up to the surface.