RESPONDING TO Gov. Charlie Baker’s urging to accelerate repairs even if that means more weekend and overnight closures, the MBTA announced a plan to step up work on the Red, Green and Orange lines.

The track replacement, debris removal, and station washing will require new weekend closures on the Orange Line from Tufts Medical to Sullivan, the Red Line from Broadway to Kendall, and the B and C branches of the Green Line during weekends this fall. That is in addition to previously scheduled work on the southwest corridor end of the Orange Line, the Mattapan trolley spur of the Red Line, and the D branch of the Green Line, which will be at least partially out of commission nearly every weekend in autumn.

The Fiscal and Management Control Board on Monday gave MBTA General Manager Steve Poftak the authority to renegotiate contracts to speed things up, and Poftak estimated that all the contractual changes would cost between $20 and $30 million.

Chief Administrator David Panagore said funding for the accelerated repairs could come from a service improvement “lock box” that includes fare hike revenue, and it could also be drawn from $50 million in budgetary surplus funds the governor wants to send to the T, or from an anticipated bump in sales tax receipts that would boost state assistance for the transit service.

After visiting the area where a derailed Red Line car crashed into signal systems, Baker in June decided the T should prioritize making repairs even if that means suspending train service and running shuttle buses during nights and weekends.

Acknowledging the disruption riders will experience when lines are out of service, Poftak said the new closures will enable the T to replace 7,000 feet of track on the B and C branches along with intersection upgrades for those trolley lines, and replace 1,800 feet of Red Line track dating back to 1986 near Park Street and Downtown Crossing, and 2,250 feet of track on the Orange Line, including some installed in the 1970s.

“We’ve attempted to be thoughtful here about where we do it and when we do it,” Poftak said. He told reporters, “We’re also planning for 2020. What are other projects we can accelerate?”

One reason for shutting down service from Cambridge to South Boston on the Red Line is that repair crews have no way to bring their construction vehicles onto the subway from the downtown area, Poftak said. The T will also speed up work improving the elevator at Harvard Station, and repair tunnel leaks, clean up trash that can cause track fires, replace stairs and station maps, and improve wayfinding signs.

North Station drawbridge replacement

MBTA officials have begun sketching out plans for replacing old drawbridges over the Charles River, which will unlock more frequent train service for travel north of Boston.

The drawbridges just outside North Station carry four tracks across the river, and T officials are planning to replace them with a six-track span, or spans, that would also enable the number of operable tracks at North Station to climb to 12, up from the current 10.

The control board on Monday authorized a $38 million design contract for the projects to the firm STV; there is not yet an estimate on what construction would cost.

There were originally four bascule bridges, built in 1930, carrying train traffic over the Charles, but in 1969 two of those bridges were dismantled, according to the T, which reported that 300 trains per day cross the structures, which are raised for boat traffic more than 3,000 times per year.

The upgrade would also improve signals, facilitate the potential electrification of the diesel commuter rail system, enable a pedestrian path over the Charles, and allow the drawbridge to be remotely operated.

The future

Looking to the future, Joseph Aiello, the chairman of the T’s control board, wants transit officials to think about automation – reasoning that if self-driving cars are in store, then there may be opportunities for automation along the fixed routes the T services.

“Maybe we ought to be doing a feasibility study about the potential for automation,” Aiello said Monday during a discussion of the T’s five-year pro forma. “It’s not going to be popular, but let’s look at it.”

During the same discussion, Transportation Secretary Stephanie Pollack noted that the T’s future finances will vary depending on the structure of the next commuter rail contract.

A few months ago, Pollack appeared to hedge on whether the T would re-bid the contract with Keolis Commuter Services that ends in 2022, as she had earlier pledged, or simply re-hire Keolis.

On Monday, Pollack said the T’s control board would need to discuss that.

“We have to talk about the commuter rail re-procurement,” Pollack said.

Green Line Extension on track

Despite some shifts in the timing of work, the Green Line Extension project remains on track, according to program manager John Dalton.

Of particular concern Monday was the push backwards from September to November for moving the commuter rail tracks, which share the right-of-way with the future trolley line, into their permanent position. The commuter rail that serves Lowell was scooted to the southwestern side of the right-of-way earlier in the construction, but that’s where the trolley tracks will eventually go with the commuter rail tracks sitting to the northeast. Moving the tracks into position before winter will be key, said Dalton.

“Count us as very worried,” Aiello responded to Dalton’s presentation.

Keeping the trolley extension project on time would also be an important demonstration to lawmakers considering the governor’s “terrific” $18 billion transportation bond bill, Aiello said. “This has got a lot of eyeballs on it,” Aiello cautioned Dalton. The $2.3 billion trolley project servicing Cambridge, Somerville, and Medford went over budget before Baker administration officials reined it back in years ago.

Despite the schedule shift for moving the commuter rail tracks, some “unforeseen conditions” such as polluted soil and groundwater and other hitches, the project is “on time” overall, said Dalton, who told reporters the board should not be concerned about the progress.

“There’s schedule changing all the time,” Dalton said. “Some things are happening earlier. Some things are happening later. This one’s happening later than planned, but the fact that we are two years away from being done with this project means there’s time to recover it.”

The project is scheduled to be completed by December 2021.

Metallurgy of derailed Red Line car

MBTA officials have taken interest in the metallurgical analysis of the trucks – or undercarriage – of the Red Line car that derailed June 11, but are not yet ready to say exactly what caused the crash.

“We don’t have any conclusions right now. Our engineers have seen preliminary results, which has prompted additional questions,” Poftak told reporters. “They’ve put that back on the metallurgical lab to further analyze.”

Whatever is contained in that analysis of the metal appears significantly relevant to determining the cause of the crash, which sent one person to the hospital and has led to enduring delays on the T’s busiest subway line.

Deputy General Manager Jeffrey Gonneville said the responses from the lab are expected in two weeks, and engineers are awaiting those answers before settling on the root cause of the crash.

Officials looking into the June crash had already ruled out operator error or a problem with the track infrastructure, suggesting that the problem lies with the Type 1 railcar that went into service in 1969, had a midlife overhaul in the late 1980s, and had its undercarriage trucks replaced in 2014.

Shortly after the crash, the MBTA conducted ultrasonic testing on all of the other 50-year-old Red Line cars, and found no systemic issues, but the T also tightened its schedule for performing ultrasonic tests, which can detect flaws in metal parts. Going forward, Red, Green, and Blue line cars will receive annual ultrasonic testing instead of testing every two years.

Since the crash, the T has restored the destroyed signals between JFK/UMass and Broadway, and officials are working to fix signals between JFK and North Quincy on the Braintree branch and JFK and Fields Corner on the Ashmont line by sometime in October.

“We should be fully restored by October, but there is a strong possibility that we’ll be able to do better than that,” Gonneville told the board.

The T has nearly restored the frequency of morning rush hour trains on the Red Line to the pre-crash level of 14 per hour, said Gonneville. As of last week, there were 13 trains per hour during the morning peak, and somewhat less than that during the evening peak.