

(Photo by Jahi Chikwendiu/The Washington Post)

Carlos Coreas (left, and Jose Salvador shine the area near the escalators at the site of Metro’s Silver Line Wiehle Avenue Station on April 29, 2014.)

Metro board members Thursday gave General Manager Richard Sarles the authority to set an official date for the opening of transit system’s new Silver Line — not that Sarles, or anyone in the agency, is willing to state publicly when that might be.

Metro took control of the line May 27 to begin testing it, a process that transit officials expect will take no more than 90 days.

But the contractors who are building the line — including four new stations in Tyson’s Corner and one in Reston — have fallen behind schedule with their final “punch list” work items. Although Metro officials have not publicly discouraged hope that the line will open this summer, they have declined to estimate a date until the contractors are closer to being finished.