Every summer, as the heat builds and the atmosphere in the subway acquires the texture of a hound dog's mouth, straphangers wonder why stations aren't air conditioned. If train cars are reliably cooled, the thinking goes, why can't something be done to cool customers while they wait for them?
The MTA answer: "Unfortunately, air conditioning of subway stations is not feasible due to the open nature of their construction and the impossibility of cooling an infinite space."
Spokeswoman Marjorie Anders explained that the system is open, in part, to cool it: the movement of trains pushes hot air from the tunnels out through vents in city sidewalks.
The exception is Grand Central Terminal, which has air conditioning in the Main Concourse, an enormous central space through which 75,000 to 100,000 passengers pass daily. Anders said seven huge cooling towers on the terminal's roof work in tandem with dozens of temperature sensors to keep the hall cool. She said that's easier to accomplish at the start of summer because "the building isn’t heat-soaked yet. The concrete, limestone and marble are still cool to the touch."
Ms. Anders spoke via phone from an office at the MTA's Midtown headquarters, which had been darkened, she claimed, to save energy. She said that though the Main Concourse is air-conditioned, the gigantic underground train shed at Grand Central Terminal, which holds its 123 tracks and 46 platforms, is not.
Ushers keep doors between the terminal and the platforms closed when trains aren’t actively boarding or unloading. And conductors on the trains only open one door per car when a train is in Grand Central.
The MTA is also coping with the heat wave by reducing the speed of subway trains and reducing electrical usage by shutting down several substations that supply power to the system's third rails. That means subways are moving a little bit slower.
The authority says it cuts back on power during heat waves between noon and 6 p.m. at the request of the New York State Power Authority.
On subway lines, passengers may notice reduced elevator and escalator service, to conserve energy. Some contracts with energy providers require the MTA to reduce power consumption during heat waves.
The MTA will also be running trains at reduced speed on Metro-North's New Haven Line, which is powered by overhead catenary wires that droop in extreme heat. "Trains are slowed so that pantographs — arm-like apparatus on the roof of the trains that draw the power from the catenary — do not get ensnared in catenary wires," a spokesman said.