After nearly a century of delays and disappointment, the first phase of the Second Avenue subway is finally opening to the public on Jan. 1, officials at the Metropolitan Transportation Authority said on Monday.

Trains will begin to run on the new line at noon on Jan. 1, 2017, the authority said in a statement. At an event to reveal the artwork at the new stations, the authority’s chairman, Thomas F. Prendergast, invited the crowd to ride the line on opening day.

“I think you’ll find the art there exhilarating,” Mr. Prendergast said. “I think you’ll find the environment vastly different than what you see in the New York City subway, and you’ll be pleased I think with the end product.”

Gov. Andrew M. Cuomo, who has been pressing officials to open the line by the end of the year, said local leaders would take a ceremonial ride on the Second Avenue line on New Year’s Eve and perhaps toast the opening of the long-delayed project with champagne.