Joe Caraballo, the stroller valet at the Prospect Park YMCA

Joe Caraballo, the stroller valet at the Prospect Park YMCA, parks up to 75 strollers a day for the overburdened parents and toddlers of Park Slope. (Photo: Christian Hansen for the New York Times)

The mothers rushed into the Prospect Park Y.M.C.A. in Park Slope, heading into prenatal yoga, art classes, or gym time. “You want long term or one hour?” Joseph Caraballo asked, as they left their strollers — some with temperature sensors and pedometers — under his watch.

He takes care to flip the canopies down so the seats won’t be too hot for the chubby thighs returning from yoga class. Except, of course, if it hides the wallet, cellphone, keys and cereal bar wrapper of an absent-minded parent.

“Is this a second-hand sale?” passersby asked, seeing 39 strollers lined up, handle-by-wheel, along 9th Street. “Are they having a race?”

But no, it’s stroller valet parking, a perfect fit notoriously spawnocentric neighborhood.

Mr. Caraballo, 52, who has a 9-year-old son, works in the Y’s maintenance department, and does not accept tips.

Erica Schohn was trying to fit her daughter, Silvia, into a Maclaren, which appeared to be the brand of choice. But Silvia would not bend, throwing back her whale-spout pony tail and arching her body. Ms. Schohn said leaving her stroller out was nice, “because then they don’t have to be folded.” (The kids, alas, do.)

Then there was the lady who left one child in a stroller and took the older one in to the gym: “She said, ‘Oh, the lady inside said I could,’ ” which was not true, Mr. Caraballo said. “I said, ‘Don’t do that.’ ”