The $11 billion, long-awaited expansion of New York’s Grand Central Terminal to serve Long Island Rail Road trains debuted Wednesday, with limited shuttle service.

The 15-year construction—one of the largest transportation infrastructure projects in the U.S. in recent years—includes eight miles of tunneling under the East River and beyond, and a 350,000-square-foot LIRR passenger concourse below Grand Central, according to the Metropolitan Transportation Authority (MTA).

Aimed at meaningfully reducing Long Islanders’ commuting times into New York, the concept for Grand Central Madison was first flouted 60 years ago.

It is the largest new train terminal to be built in the United States since the 1950s and the first LIRR expansion in more than 100 years, according to the MTA.

Grand Central Madison is on Manhattan’s East Side, 15 blocks northeast of Penn Station, where LIRR passengers now enter the city—saving commuters precious time.

For the first three weeks, Grand Central Madison will only handle limited service between Jamaica, Queens, and Grand Central.

This will be followed by full service from all 11 branches of LIRR into Grand Central.

Grand Central Madison was originally scheduled to open in December but was delayed when safety testing had not been completed, according to Jamie Torres-Springer, president of MTA construction and development.

When the regularly scheduled LIRR trains begin in mid-February, they will operate from 6:15 a.m. to 8 p.m. weekdays and from 7 a.m. to 11 p.m. on weekends. Peak trains will run every hour in both directions, and off-peak trains, during weekday midday periods and weekends, will run every half an hour.

Grand Central Madison and Penn Station will honor one another’s tickets, as they will be in the same fare zone.

The additional trains into Grand Central Madison will add 274 trains to LIRR service on weekdays and serve 162,000 people a day, MTA said.

The new train system will also transport people from JFK Airport to Grand Central in just 40 minutes.

Additionally, Grand Central Madison will house 25 retail stores and offer WiFi and cellphone service, art installations and digital train schedules throughout.

MTA and LIRR will issue a new schedule in the near future, officials said. Train information can be found here.