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by anonymous_sorry
941 days ago
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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. [1] https://www.standard.co.uk/news/london/tube-underground-lond... |
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The tunnels have absorbed heat over the decades, venting yet more heat into the tunnels is not going to work.
More space would make the engineering easier, but it's not the fundamental issue.