Here’s the next MBTA shutdown, this time on the Orange Line

Riders will experience disruptions in Orange Line service throughout much of October, the MBTA said.

Passengers walk through the turnstiles below a train arrival clock at the Massachusetts Avenue Orange Line MBTA station in Boston. Aram Boghosian for The Boston Globe

Orange Line riders should expect disruptions to their commute in the coming weeks, the MBTA said in a reminder on Monday.

Parts of the Orange Line will be shut down from Oct. 8-20, and then again from Oct. 26 -Nov. 1, the MBTA said. The first shutdown primarily extends between Back Bay and Forest Hills, while the second shutdown is focused on the northern section of the Orange Line.

The MBTA said these shutdowns are “critical” for the MBTA’s Track Improvement Program, which aims to replace tracks and get rid of slow zones.

Oct. 8-11, 15-20

The MBTA plans to shut down service between Back Bay and Forest Hills during Oct. 8-11 and 15-20. Free shuttle buses will replace regular service, including making a stop at Copley to connect riders to the Green Line.

In the reminder, the MBTA also encouraged riders to consider the Commuter Rail in their commute for free service between Forest Hills, Ruggles, Back Bay, and South Station. The MBTA said it takes about 10 minutes to go from Forrest Hills to Back Bay on the Commuter Rail.

Oct. 12-14

Track work will is planned from Forest Hills all the way to North Station between Oct. 12 and 14. While shuttle buses will run from Forest Hills to Back Bay, again stopping at Copley, the MBTA said shuttle buses will not run all the way to North Station.

Instead, the MBTA advised riders to switch to the Green Line at Copley. The Green Line, which runs mostly parallel with the Orange Line through Downtown, will have increased service to “accommodate anticipated increases in ridership,” the MBTA said.

Oct. 26-27

The MBTA said shuttle buses will replace service between Oak Grove and Ruggles due to more track work and “station upgrades.” Riders north of downtown should use the Haverhill Commuter Rail line for alternative service into downtown, the MBTA said.

Oct. 28- Nov. 1

The breadth of the second shutdown will decrease slightly from Oct. 28-Nov. 1 when the MBTA suspends service between Oak Grove and North Station. Again, the MBTA said shuttle buses will take riders between the two stops.