A $1.8 billion facility intended to connect Metro light-rail lines under downtown Los Angeles is 90% complete and test runs of trains are underway, officials said Monday.

The Regional Connector Project was designed to save commuters’ time by eliminating transfers between trains, allowing one-seat rides across Los Angeles County.

“The trackwork, the rail guideways, the platform areas are now complete,” Los Angeles Mayor Eric Garcetti told a press conference. “We’ve been waiting for like 10 years.”

County Supervisor Hilda L. Solis, board chair of the Los Angeles County Transportation Authority, said the connector will open later this year.

The overall project is a 1.9-mile (3.06-kilometer) underground light-rail extension connecting the A, E and L lines and three new stations, including the Grand Av Arts/Bunker Hill Station about 100 feet beneath ground level.