BOSTON (AP) — Beleaguered commuters in the greater Boston area were dealt another setback Wednesday when transit officials announced that service cuts on three of the four major subway lines in the city that were set to end this summer will instead extend into the fall.

At the same time, dozens of bus routes will operate with reduced frequency starting next week as the Massachusetts Bay Transportation Authority grapples with ongoing staffing shortages amid a chaotic transit landscape.

The change will mean that fewer trains will continue to run on the system’s Red, Blue, and Orange lines into the fall. The reduction in service began June 20, with the number of trains dropped to Saturday levels after the Federal Transit Administration pointed to dangerous understaffing at the agency. It’s unclear when the T will resume normal schedules on the three lines.

To complicate matters, a section of the Green Line has also shut down for a month for the completion of construction work.

MBTA General Manager Steve Poftak told reporters Wednesday that the transit agency is prioritizing safety and that the service reductions will remain in place until there is an “adequate level of staffing” at the MBTA’s operations control center.

Also Wednesday, the MBTA announced in a press release that beginning next week 43 bus routes will operate with less frequency during varying times of day. Nine routes will experience some routing changes and over thirty routes will see departure time changes.

MBTA officials said the agency is continuing an aggressive hiring campaign for bus operators, including a sign-on bonus of up to $4,500. Since January, the agency has hired 152 bus operators and needs about 300 more drivers.

The announcements came as commuters were already dealing with an unprecedented 30-day shutdown of the Orange Line.

The 11-mile (17.7-kilometer) subway line that runs from the city of Malden north of Boston to the city’s Jamaica Plain neighborhood was closed so the MBTA can make track and signal repairs.

Poftak has called the decision to shut down an entire subway line for a month “unprecedented” but said it will give workers access to the tracks 24/7, rather than trying to squeeze repairs in during overnight hours and weekend shutdowns.

Those improvements — including work replacing 3,500 feet of 38-year-old Orange Line tracks that could take five years to finish using overnight and weekend hours — will be accomplished during the shutdown, according to transit officials.

The Orange Line is scheduled to resume service the morning of Sept. 19.

The T is providing shuttle buses between stations, and the city has set aside designated bus-only travel lanes on some streets. Commuter rail lines are also running with increased frequency.

The T has also deployed hundreds of workers to help commuters navigate the new system.

The Orange Line normally handles about 100,000 trips per weekday, according to the MBTA.