The Massachusetts Bay Transportation Authority did not respond to a request for comment Tuesday. General manager Steve Poftak is set to make an announcement about “accelerated infrastructure upgrades to the MBTA” on Wednesday at Wellington Station alongside Governor Charlie Baker and Secretary of Transportation Jamey Tesler, according to the governor’s public schedule.The MBTA’s board of directors scheduled a last-minute meeting for Wednesday morning to review a contract with A Yankee Line, a company that often provides shuttle buses for the MBTA when it shuts down parts of its subway lines.Former Massachusetts secretary of transportation Jim Aloisi said that if the T shuts down the entire Orange Line for 30 days, it would likely be a first.“There may be a small precedent, but nothing on this scale,” said Aloisi. “This is a drastic step.”The Orange Line’s 20 stations serve as an essential transportation option for entire communities. The average number of weekday trips as of October 2021 was 104,000, according to an MBTA presentation from earlier this year. By comparison, average weekday trips on the Blue Line were 41,000, the Green Line, 94,000, and the Red Line, 125,000.The plan to shut down the Orange Line comes after a year of safety incidents on the MBTA.Since a Green Line collision in July 2021, the T has been beset by troubles: An escalator malfunctioned at Back Bay Station causing a bloody pileup and injuring nine people, a commuter rail train killed a woman in her car after a crossing signal in Wilmington malfunctioned, another two Green Line trains crashed and derailed injuring four people, and a man was dragged to his death by a Red Line train at Broadway Station after his arm got caught in a subway door.The death brought intense scrutiny from federal transit safety regulators who began a nearly unprecedented inspection of the subway system in mid-April. The Federal Transit Administration is expected to release its final report about the T this month.In June, the FTA said it found that the MBTA didn’t have enough dispatchers to safely operate its subway, so the agency cut service on the Orange, Blue, and Red lines by more than 20 percent. Federal inspectors also said the T needed to fix and upgrade large swaths of its subway tracks.The FTA found that around 10 percent of the MBTA’s subway tracks are under speed restrictions due to defects, including a years-long slow zone on the Orange Line tracks between the Tufts Medical Center and Back Bay stations. Track maintenance crews use a 2- or 2½-hour window to complete fixes overnight, not nearly enough time, the FTA said.The MBTA has already made progress on repairing a stretch of defective Orange Line tracks that has caused the years-long slow zone, the agency told board members last month.It’s not just tracks that are a problem. Old Orange Line cars, put into service from 1979 to 1981, never had a midlife overhaul. Last month, one of them caught fire when a side panel fell off and touched the electrified third rail, causing passengers to frantically flee.In 2014, the MBTA selected a Chinese company that far underbid competitors to build an assembly factory in Springfield and deliver hundreds of new Orange and Red Line cars.As of last month, the T had received 78 of 152 new Orange Line cars and just 12 of 252 new Red Line cars, MBTA spokesperson Joe Pesaturo said on July 22. The T expects all new Orange Line cars to be delivered by summer 2023 and all new Red Line cars by summer 2025, Pesaturo said.The company, CRRC MA, has said the COVID-19 pandemic and supply chain issues are causing the delays.Boston Mayor Michelle Wu called for a more aggressive approach to fixing the T’s aging infrastructure during a radio interview last week.“It is time to talk about just ripping the Band-Aid off and taking drastic action,” she added during a July 25 interview on WBUR’s “Radio Boston.” She suggested shutting down sections of the Orange Line and said Boston would be prepared to devote street space to shuttle buses.Wu reiterated that commitment Tuesday.“We’re at the point with the T that we can’t keep kicking the can down the road anymore,” she said to reporters at an unrelated event. “We would work very closely with the agency to make sure that Boston is prepared to help support any additional alternatives and to make sure that the work actually happens during this period to have a real impact so that we would see that service improvement.”Taylor Dolven can be reached at [email protected] Follow her on Twitter @taydolven.