Metro General Manager Richard Sarles says that next Monday he might announce “a firm date” for the planned opening of the Silver Line this summer, bringing rail service to the Tysons Corner and Reston areas at last.

A week after the transit agency’s operations chief complained publicly that the Silver Line’s builders had fallen behind schedule with final “punch list” work items, Sarles indicated in a conference call with reporters Monday that the contractors had picked up their pace in recent days.

“There are about seven or eight items that are scheduled to be completed this week,” he said. “If those items are completed this week, and fair progress is made regarding the rest of the items, I will be prepared [next Monday] to give everyone in the region the firm date for the start of revenue service.”

“Revenue service” is Metro-speak for trains carrying fare-paying passengers. The $2.9 billion first phase of the long-delayed Silver Line project is nearly 12 miles of tracks, from the East Falls Church station on the Orange Line to Wiehle Avenue in Reston, and includes a new station at Wiehle Avenue and four new stations in Tysons Corner.

In a conference call last Monday, Rob Troup, Metro’s deputy general manager for operations, said the Silver Line contractors were “behind schedule on approximately half” of the 33 punch-list work items. “Does it concern us?” Troup said at the time. “There’s no question it concerns us.”

The project, being overseen by the Metropolitan Washington Airports Authorities, is being built by a group of contractors led by construction giant Bechtel. Troup’s public jab at the contractors, known collectively as Dulles Transit Partners, seemed intended to goad them into getting back on schedule.

Troup’s boss, Sarles, struck an upbeat tone in this week’s conference call, saying Metro had been “given some revised completion dates” for the punch-list items, which Sarles said was a hopeful sign.

“Some of the things that were of concern last week had to do with progress,” Sarles said. The revised completion dates involve “the seven or eight items” now due to be finished this week. “So if they live up to that, and don’t fall behind, that gives me confidence that they’re back on track.”

He said: “When you set a firm date, it’s based on progress you’ve made up to that point. Now we’re getting to the point where, if the work is done this week that is scheduled to be done, then my level of confidence will be high enough to establish a firm date for revenue operations.” He added, in a note of caution: “If the work is done this week, then I will be confident. I’m not confident until I see the work is done.”

The Tri-State Oversight Committee, a safety watchdog group that oversees Metro’s operations, has conducted its mandatory review of the Silver Line and “given us a preliminary report, which we will be responding to,” Sarles said. “We’ve been moving ahead with out own familiarization [with the Silver Line] for maintenance folks and operations folks. … And we are continuing to do outreach to make people aware of the system. Those things are all going according to schedule.”

For weeks, Sarles and others at Metro have declined to publicly specify a date when the Silver Line might open, saying they did not want to do so until they were confident of when the construction would be finished.

As hopeful as Sarles sounded in Monday’s call, he still would not mention a date, saying he wanted to wait a week.

“We are in the final stretch,” was as specific as he would get.