What riders need to know about partial Red Line shutdown

Some Red Line riders will need to make extra time for their commute over the next two weeks as the Ashmont branch and Mattapan Trolley will be closed for track repairs and other improvements to eliminate slow zones. Here’s what you need to know.

When does the shutdown begin — and end?

The 16-day closure, which the MBTA announced in August, begins Saturday and runs through Oct. 29. Free shuttle buses will replace train service from JFK/UMass station to Ashmont and Mattapan stations, and rides on the commuter rail’s Fairmount Line from stations in Zone 1A will be also be free, the MBTA said.

The Ashmont branch, which stops at Ashmont, Shawmut, Fields Corner, and Savin Hill stations, carries about 40,000 riders each day, while the Mattapan line carries about 3,700, the MBTA said. They include some of the system’s oldest rails, which need to be replaced, according to the MBTA.

Why is the MBTA shutting down the two lines?

The suspension “will enable us to work around the clock and achieve repairs and upgrades that would take six months if we had to do them while the system is operating without interrupting service,” the MBTA said on its website.

The closure will allow workers to replace more than 8,000 feet of rail, as well as track ties and ballast, between Ashmont and JFK/UMass and between Ashmont and Mattapan. Workers will also repair lighting, remove overgrown vegetation, and improve accessibility at stations.

The MBTA said the work will allow trains and trolleys to run at regular speed — between 25 and 40 miles per hour on the Ashmont line, and about 25 miles per hour on the Mattapan trolley. The two branches had 38 speed restrictions in place on Thursday, keeping trains under 10 miles per hour in both directions, according to an MBTA dashboard.

“Under the planned work, all 38 of these speed restrictions will be lifted following the upcoming diversion,” MBTA spokesperson Lisa Battiston said in an email Thursday.

Will the rest of the Red Line be affected?

No. Service on the Red Line’s Braintree branch and from JFK/ UMass north through downtown will not be affected.

How often will shuttle buses run?

During peak commuting hours (from 7 a.m. to 9 a.m. and 4 p.m. to 6:30 p.m.), shuttle buses will run between JFK/UMass and Ashmont every two to three minutes, and between JFK/UMass and Mattapan every 12 to 15 minutes, the MBTA said.

During off-peak hours and on the weekend, buses will run every seven to eight minutes between JFK/UMass and Ashmont, and every 12 to 15 minutes between JFK/UMass and Mattapan.

What about switching to the commuter rail during the shutdown?

Some riders may choose to take the commuter rail during the shutdown. The Fairmount Line stops at Blue Hill Avenue station (about three-10ths of a mile from the Mattapan MBTA station) and at Talbot Avenue station (about seven-10ths of a mile from the Shawmut station).

Commuter rail trips on the Fairmount Line will be free for riders boarding at stations in Zone 1A, which includes South Station, Newmarket, Uphams Corner, Four Corners/Geneva, Talbot Avenue, Morton Street, Blue Hill Avenue, and Fairmount, the MBTA said.

Are there bus options?

Yes. The 18 bus connects to Andrew, Savin Hill, Fields Corner, Shawmut, and Ashmont stations; the 22 bus connects to Talbot Avenue on the Fairmount commuter rail line; the 24 bus connects to Ashmont and Mattapan stations; the 28 and 31 buses connect to the Mattapan and Blue Hill Avenue stops on the Fairmount commuter rail line; and the 30 bus stops near Blue Hill Avenue and Mattapan stations, the MBTA said.

More information about the closure and alternative travel options is available on the MBTA’s website.