You know how Park Street Station is an airless tomb from June to August? Just like all the other underground T stations, which are also sweltering and breezeless in summer? Well, theyâ€™re not hot because of global warming or substandard building codes of generations past. The real reason the T is stuffy and hot is the fault of modern improvements, according to Gerry Oâ€™Regan, railfan and officer of the Boston Street Railway Association.
â€œBack before air conditioning was popular, the tunnels used to be nice and cool in the summer,â€ he says. â€œThey used to be where you went to get cold in the summertime.â€
Which makes sense, because theyâ€™re underground, a place where temperatures arenâ€™t as extreme as they are on the surface. Thatâ€™s why before refrigeration, people had root cellars. Thatâ€™s why small animals in deserts (and people in Australia, while weâ€™re at it) live in burrows and dugouts. Because of this, the T tunnels were designed with an average temperature of 50-60 degrees in mind, and kept breezy with a ventilation system of vents that let air from the tunnels into the cars.
So what went wrong? Why are the once-cool tunnels now sweltering doldrums of death?
â€œItâ€™s because the cars are air conditioned,â€ Oâ€™Regan says. â€œIt heats the air discharged back into the tunnels, and works as a heat pump. Itâ€™s hot in summer because air conditioning is on. And the electronics in the cars and tunnels give off heat, too, which means that additional heat gets pumped back into subway. And thereâ€™s nowhere it can go.â€
(via Universal Hub)