The Subway Doesn't Have to Be Hot and Gross
20 years ago, the MTRC in Hong Kong started to install platform screen doors to seal off the platforms and reduce their air conditioning bill as most of the cool air was of course just going into the tunnels.
That investment paid for itself within a few years.<p>Evacuating the heat from the train is another issue that must be addressed but it’s far from being an unaddressable one and there are already many examples of other cities implementing workable solutions.<p>Having doors installed along the platform has a number of advantages beside air conditioning: increased safety (no more suicides and accidents), more platform capacity since people can get right to the edge of the platform, potential increase in network capacity since trains can enter the station faster as they don’t have to slow down early to enter the platform at low speed to avoid passengers accidents.<p>Older networks like London, Paris and New York have a much harder time implementing these measures as they are often very deep and their infrastructure are old and quite vast, but they each have projects to tackle these issues, although in the case of New York, the cost will probably slow down adoption (not least because of the crazy Union requirements).