City officials cut the ribbon Sunday for the No. 7 line leading from Times Square to Manhattan's far West Side at 34th Street.
The first train arrived at the station at 34th Street and 11th Avenue, and will be the end of a 34 minute ride from the Main Street-Flushing station in Queens.
After almost eight years of construction, the station is expected to handle 35,000 riders each rush hour.
The 34th Street - Hudson Yards station was built as part of the 7 Subway Extension, taking subway riders to the Hudson Yards, a development of residential, retail and office space still under construction.
The station was originally envisioned in the city's failed bid for the 2012 Summer Olympics as transportation to a New York Jets stadium that fell through. Numerous delays followed, mostly because of equipment failures. Construction began in 2007.
The city financed the entire $2.4 billion project, a centerpiece of former Mayor Bloomberg's plan to bring development to the far West Side.
The MTA distributed video of the station in May.
Mayor Bloomberg took the inaugural run on the line's extension in December 2013.
The MTA predicts that the extension reaching to near the High Line and the Hudson Yards development will make this the busiest station in the subway system.
The station extends the No. 7 train 1 1/2 miles past its current last stop in Times Square, and it's the first station added to the system since 1989.
The station will serve the new Hudson Yards project - about 17 million square feet of office, residential and hotel space being built where only rail yards used to be. Transit officials point out it's the only subway line serving the area west of Ninth Avenue below 59th Street.
"It is the centerpiece toward redeveloping the far west side," said Metropolitan Transportation Authority spokesman Kevin Ortiz.
Construction on the $2.4 billion project, financed by the city, started in 2007 under Mayor Michael Bloomberg and was initially projected to be completed by December 2013, but officials pushed that back several times. Ortiz said the delays stemmed from making sure components like escalators, elevators and some communications systems were in place and running properly. The station is the first in the system to have elevators that travel on an incline like escalators do, and will also maintain a steady temperature of between 72 and 78 degrees on platforms no matter the outside weather. The station is airy, with a multi-hued mosaic on its ceiling and shiny metal railings leading to the platform level.
The 7 line extension is one of three major transportation projects the MTA has been working on. The East Side Access project, slated for completion in December 2022, is bringing new tunnels to Manhattan and Queens and a new concourse underneath Grand Central Terminal. The Second Avenue Subway is bringing a new line along Manhattan's far east side, with the first segment from 96th street to 63rd street expected to be complete in December 2016.
Richard Barone, director of transportation programs for the Regional Plan Association, said the new extension is different from the other two not only in terms of how it was financed - with the city putting up the money instead of state and federal dollars being used - but also because of the level of interaction between the MTA, the city and the Hudson Yards project developer that integrated transit and land use.
"It's really about spurring redevelopment of an area that was pretty much inaccessible," he said. The other two projects, he said, are about relieving congestion and improving transit access in already developed areas and are being paid for more traditionally.
Commuter advocate Gene Russianoff, of The Straphangers Campaign, agreed it was about redevelopment, and didn't consider it "a giant step forward for the system."
He pointed out it was only one new station. Initially, another had been planned for 10th Avenue and 41st Street but was cancelled over cost issues.
"It has more to do with real estate than it has to do with serving the riding public," he said, adding that the other infrastructure projects would do more.
"It's not a bad thing," he said. "It's just not the top priority."
(The Associated Press contributed to this report.)