On a recent afternoon on the Lexington Avenue line’s downtown platform at Grand Central, Ajah Harley waited for his train and did what pretty much all of his fellow subway riders do at this time of year: sweat.
“Oh, my God, it feels like a boiler room,” said Mr. Harley, a student at Fordham University, describing how his August subway rides have been going so far. “The sweat is coming down your face. You wipe it off and then it’s just right back on your head.”
Anchored to the ceiling above Mr. Harley’s head, a growling blower expelled a steady blast of air a few degrees cooler than the tropical climate of the platform. But Mr. Harley didn’t think it was doing much good.
“I don’t know,” he said. “It feels like hot air.”
That was not the intention. The blowers are known as spot chillers, an innovation from 2000 and a noble experiment in battling the subway station’s equatorial temperatures.
Twenty-two years ago, the chillers’ arrival stirred hopes that they might appear in other stations, too, finally settling the question that looms in the mind of every commuter come August in New York: Why can’t our subway stations have air-conditioning?
But according to Jamie Torres-Springer, who leads the M.T.A.’s construction department, the spot chillers were more a product of geographic luck than a harbinger of systemwide AC.
“Grand Central has a full chiller plant,” Mr. Torres-Springer said. The equipment that keeps the terminal upstairs cool “is the source of the chilled water, which is then circulated throughout those units to provide spot chilling on the platform.”
But in engineering terms, “the basic fact is that an old system like our subway system isn’t designed for air-conditioning,” Mr. Torres-Springer said. Almost every mile of track is open to the atmosphere via stairways and sidewalk grates.
“For the same way that your air-conditioner doesn’t work well if your windows are open, air-conditioning isn’t effective on a subway platform, he said.
Hotter summers and the concentration of sweaty bodies contribute to the torrid conditions underground, but the chief culprit is the subway trains themselves.
In the postwar years, riders started demanding air-conditioning to replace fans that did little more than circulate stale air. With the purchase of 600 air-conditioned cars in 1967, the Lindsay administration got the ball rolling, but it would take until 1993 for the Transportation Authority to declare that 99 percent of its cars had AC.
Unfortunately, the air-conditioners that remove hot air from the cars dump it directly into tunnels and stations, which do a fine job of trapping it.
In this way, the temperatures of both train and station have been linked for the last half-century.
It’s worth pointing out that temperatures are noticeably lower in the system’s newest stations, including the 7 line’s 2015 extension to Hudson Yards and the three new stops on the Second Avenue subway, which opened in 2017.
The agreeable atmosphere down there owes itself to cooling towers, where fans draw air across pipes filled with a mix of cold water and glycol. In Transit Authority parlance, it’s called “air-tempered climate control.”
“It’s not a full air-conditioning solution,” Mr. Torres-Springer said. “But it can keep the temperature about seven to 10 degrees cooler than the ambient temperature, and it helps to reduce humidity in the station, which is valuable.”
A similar cooling system for Grand Central Terminal — this one in the form of a 3,000-ton chiller plant — had the capacity to cool the station below, too, said Charles C. Copeland, president of consulting engineers Goldman Copeland, and the man who designed the chiller plant.
“When I was designing it, they came along midway and said, ‘Can you give us some cooling for the local subway line?’” Mr. Copeland said.
That is the only reason those coolers perched over the 4, 5 and 6 subway platforms are there at all.
This coincidence is also why we won’t be seeing chilled air pumped into older subway stops. “Other stations don’t have chiller plans,” Mr. Torres-Springer said.
But what if they did? When asked to ballpark the cost of retrofitting the entire system with spot chillers, Mr. Torres-Springer declined. (“I don’t even know how we would begin to go about estimating that,” he said.) But here’s some back-of-the-envelope math: Grand Central’s 43 chillers cost around $10 million when they were installed in 2000, or about $17 million in today’s dollars. Multiply that by the 281 underground stations and you land in the neighborhood of $4.8 billion.
“It’s a big number, even given the way the M.T.A. spends money,” said Danny Pearlstein, the policy and communications director for the Riders Alliance, a nonprofit that advocates for better public transit in New York.
But Mr. Pearlstein has a faster and cheaper solution to the problem of sweltering subway stations. “Run more air-conditioned trains to whisk people off the platform more quickly,” he said.
Or you can take the advice of author and subway historian Stan Fischler, who recalls a time when a sultry subway — trains and platforms both — was simply the price you paid to get where you were going.
“This is part of being a New Yorker,” he said. “You grin and bear it.”
