Buses will replace Orange Line service between Oak Grove Station and Sullivan Square Station from 9 p.m. to the end of service every Sunday through Thursday from July 8 to December 28, MBTA spokesman Joe Pesaturo said.
The buses will be needed while crews perform track, power, and signal work between Wellington and Sullivan Square for the Orange Line's Assembly Square Project, Pesaturo said.
An estimated 2,400 riders a night are expected to use the shuttle buses during the service change, which should add 10 to 15 minutes to trip times, he said.
On nights when an event is being held at the TD Garden, all Orange Line trains will be in operation until the event has cleared.
Construction on the $29 million Assembly Square Station is set to finish in fall 2014, according to the MBTA's website.
There will also be six weekends this fall - one in September, two in October, and three in November - during which buses will replace trains between Oak Grove and Sullivan Square, Pesaturo said.