Despite strong pushback, the MBTA is barreling ahead with significant service reductions for early next year, cutting the frequency of subway and bus trips, some commuter rail weekend service, ferry schedules, and more in a move to reduce costs amid a pandemic-fueled budget crunch.

With a 3-2 vote that capped off months of planning, public outcry and debate, the T’s Fiscal and Management Control Board on Monday approved virtually all of the changes that MBTA staff had proposed, resurfacing long-simmering frustrations over the transit agency’s funding and leaving unclear when or how services will be restored.

The board made a handful of changes aimed at keeping some commuter rail service after 9 p.m., setting a target date for determining if the agency needs to increase service, and ensuring that fare hikes — which had not been recently proposed — will not factor into the agency’s upcoming budget deliberations.

Cuts set to hit in January and March are scaled back from an earlier proposal and aimed only at the second half of fiscal year 2021. MBTA officials plan to decide in the spring whether to keep them in place, restore some service, or implement additional cuts in FY22, which begins July 1.

“Part of the reason why we have somewhat bifurcated the decision-making in this process is we want to see what we learn over the next few months,” MBTA General Manager Steve Poftak told reporters ahead of Monday’s meeting.

Under the plan unveiled and approved on Monday, the T will halt weekend commuter rail service on all but five lines starting in January, as well as reduce Hingham and Hull ferry service and cut all Charlestown and Hingham direct ferry service to Boston. Weekend service will remain available, but less frequent, on the Worcester, Providence, Newburyport/Rockport, Middleborough, and Fairmount Lines, which officials say together represent about two-thirds of the commuter rail’s COVID-era weekend ridership.

Other major changes will hit in March: 20 bus routes will be eliminated; frequency will drop 20 percent on non-essential bus routes and 5 percent on essential bus routes; gaps between Red, Orange, and Green Line trains will increase 20 percent; Blue Line trains will run up to 5 percent less frequently; and more commuter rail cuts will arrive, including possible reductions in service after 9 p.m.

Commuter rail operator Keolis cut the system’s weekday schedule by more than half this week to cope with a Covid-fueled staffing shortage. Citing “low employee availability because of Covid-19 absences,” the company said it would slash regular weekday service from 541 trains to 246 trains for at least two weeks. The change went into effect on Monday.