Red Line service between JFK/UMass and Braintree stations will be suspended from Sept. 6 to 29 for track improvements

Passengers were reflected in a window as they boarded a shuttle bus to Alewife after Red Line service on the T was disrupted in July.Jessica Rinaldi/Globe Staff

Red Line service between JFK/UMass and Braintree will be suspended from Sept. 6 to 29 for track renovations aimed at increasing train speed, MBTA officials announced Thursday.

In replacement of the connections, free shuttle buses will make stops at Braintree, Quincy Adams, Quincy Center, Wollaston, North Quincy, and Ashmont, officials said. There will be no direct shuttle bus service to or from JFK/UMass.

A guide to the suspension between JFK/UMass and Braintree on the Red Line.Massachusetts Bay Transportation Authority

MBTA officials said riders who choose to use shuttle buses during this closure should plan for longer travel times.

“For example, a rider travelling to Park Street from Braintree should anticipate an extra 40 minutes in addition to their regular commute,” officials said.

Commuter rail lines that run between Braintree, Quincy Center, JFK/UMass, and South Station will also be free, officials said. They recommend this service for faster travel.

Personnel will be available at Braintree, Quincy Center, and JFK/UMass during weekday rush hour periods to help riders find alternative commuter rail trains, officials said.

The T also announced changes in commuter rail service on weekends.

The Kingston, Middleborough, and Greenbush Commuter Rail lines, which run adjacent to the Red Line, will be suspended between South Station and Braintree during the weekends of Sept. 7 to 8 and Sept. 14 to 15, officials said.

Shuttle bus service between South Station and Braintree will be deployed in replacement, officials said. It will only stop at those two locations.

This temporary closure is a part of the Track Improvement Program, that aims to repair 18 miles of track and remove over 20 speed restrictions.

Once completed, the track work will improve round-trip Braintree Branch travel times by as much as 24 minutes, running service up to the maximum allowable speed of 40 miles per hour, officials said.

The improvements also lay “the groundwork for raising current Red Line train speeds above that,” officials said,

There are no other planned subway or commuter rail service changes for September, officials said. More information can be found at mbta.com.