It will probably take another 10 years to build Oahu’s 20-mile, 21-station transit line all the way to Ala Moana Center, according to the Honolulu Authority for Rapid Transportation’s latest estimates.

Nathaniel “Nate” Meddings, HART’s director for project controls, is slated to brief the agency’s board on the new 2031 completion date — and the methodology behind it — at the next full board meeting on March 18, HART executive director Lori Kahikina told Civil Beat on Wednesday.

Meddings will also brief the board on HART’s official new cost estimate for the project at that meeting, Kahikina said. Updated unofficial estimates last fall put the cost at around $11 billion.

Kahikina said HART has just finished its new so-called “estimate at completion” cost — the official cost — and that’s what the board will hear on March 18.

Rail’s scheduled completion date, like its cost estimate, has been a moving target. In November, city leaders outside of HART said it could take until 2033 to finish the line to Ala Moana Center.

HART, however, said at the time that 2033 “was not an official HART number” and instead said it could deliver the full transit line in late 2027 or 2028. Now, under new leadership, the official HART number has been moved to 2031.

The full 20-mile, 21-station line was originally supposed to be ready for service by January 2020.

HART still aims to have the line’s first half, to Aloha Stadium, ready for service by the end of this year. It’s not clear yet when the city might start that service, however.