In the summer of 1904, as the New York subway system neared completion, a New York Times journalist tagged along with then-mayor George McClellan and his associates on a tour of the new system. “With the temperature above ground such that men and horses were dropping in the streets, the Mayor of New York and his party rode about under the city with coats buttoned close and in perfect comfort,” the reporter wrote. With the dank underground air, the “temperature could not have ranged much above 70 degrees in any part of the subway.”
Turn-of-the-century commuters weren’t, it turns out, living in a better time. The mayor simply experienced the subway without the main factor that makes our waits so hot and uncomfortable: modern trains, with their heat-releasing brakes and air-conditioning systems belching humid exhaust. On an average New York summer morning 105 years later, it was 92°F in the sun outside the 86th Street, Lexington Avenue station, but down below, temperatures reached 96°. On the 14th Street platform it was also 96° — under the fans that blast air down from the ceiling.
New Yorkers aren’t alone in their suffering. The London Underground, which opened in the 1860s, has withstood summer temperatures as high as 116°. (The Underground posts signs advising customers to ride with water bottles, and its Cooling the Tube program has devoted a couple hundred million pounds to test efforts like putting massive blocks of ice in the trains.) The Paris Métro, which opened in 1900 and carries 4.5 million riders a day, also heats up in the summer — although it pumps in a perfume called Madeleine to mitigate the stench.
But hot, muggy conditions aren’t a necessary evil. Look at Washington, D.C.’s underground train system. In a Washington Post article earlier this month, a reporter visited eighteen different D.C. stations and found that the hottest ones peaked at 90°F, while the coolest topped out at 79. While D.C. suffered under the same mid-90s heat as New York, its stations averaged temperatures in the mid-80s.
So what makes the capital’s system so comfortable? The Washington Metro, opened in 1976, was built extremely deep, where the air is naturally cooler. (The city’s Wheaton Station is at the bottom of a 508-foot escalator, the longest automated stairway in the Western Hemisphere.) The heat from train air conditioners and brakes dissipates more readily under D.C.’s high ceilings. But more important, the D.C. system was built with “chiller units,” which use water to cool incoming air. The 47 underground stations each have between three and thirteen of these units, depending on their size and layout.
There’s little formal ventilation in the majority of New York City stations. Instead, air is passively released through ceiling grates and circulated when trains blast through the tunnels. (It’s impossible to provide air conditioning in stations, because the system wasn’t built with space for the machinery, and there are too many openings to the street.) In 1999, the MTA did begin installing a system called regenerative braking, which captures some of the released heat from the trains’ brakes and feeds energy back into the third rail, but that changed little.
However, New York’s system now has a few D.C.-style chiller units — some were installed in Grand Central’s 4,5,6 station during the Terminal’s recent restoration, and there are four in the brand new South Ferry station. The long-delayed Second Avenue line, now slated to open around 2018, will also utilize them. Says MTA Capital Construction chief engineer Joe Trainor: “There will be an air ventilation system in the Second Avenue line which will mechanically move the air around. It’s actually a system with ducts and fans.” Unfortunately, the MTA has no plans to install chillers in other stations. Charles Seaton, a spokesperson for NYC Transit, says the units go in the ceiling, and there’s just no room for them in the current system. We won’t see them, sadly, “in our lifetimes.”