It is no different from any other Subway, with a kitchen, a walk-in freezer, a service counter and refrigerators for drinks. One level down, there is a heated and air-conditioned lounge with tables and chairs. A compost tank and an evaporator in the bottom container take care of all the solid and liquid waste.

Image The Subway restaurant, in cargo containers stacked three tall, sits between cranes that are raised as the building goes up. Credit... Fred R. Conrad/The New York Times

Visibly nervous in a structure seemingly hanging in midair, Richard Schragger, an accountant turned restaurant franchise owner, stood behind the cash register offering free cookies to his burly patrons on the first day of business.

The menu, for now, is instantly recognizable to any connoisseur of the chain. But Mr. Schragger may add ready-to-heat lasagna, burgers, hot dogs and pretzels to the usual $5 footlongs to infuse the shop with a sense of variety. There is also talk of adding Papa John’s pizza. After all, he must cater to the whims of his clientele.

“I don’t think the veggies will be a big seller,” said Mr. Schragger, who owns four other Subways in Manhattan. “I imagine most of the guys will want protein. Philly Cheesesteaks and the Feast.”

Brett Davis, a young ironworker, was thrilled to be able to relax while eating his lunch, instead of having to race to and from the hoist. “I got an Italian B.M.T.,” he said, “what I always get from Subway.”

The shop is open to ironworkers, who work at the top of the building as it goes up, as well as laborers, concrete workers, electricians and others on the lower floors; at any time more than 1,000 people can be on the job site. But they are not required to eat at the Subway. Business was a little slow Wednesday for what Mr. Schragger called a “soft opening,” but he and DCM are hoping the shop will catch on.

“It’ll be real nice in the winter,” said Rod Carril, an ironworker.

DCM reviewed nine companies interested in opening a restaurant in an unfinished skyscraper. DCM wanted good food that could be prepared elsewhere and that required minimal packaging, so most of the waste could be “composted and compacted,” said Nancy Wickham, the DCM office manager who organized the selection process.