For two months, beginning on March 1, users of the Fitchburg commuter rail line will need to use replacement bus service over a long stretch of the line, a switch that will add to travel times.
The MBTA on Monday announced its plans, which will affect service from the Littleton/Rte. 495 station through stops in Acton, Concord, Lincoln, Waltham and Belmont, with bus service delivering passengers to Alewife Station on the Red Line.
The T says the diversion is needed to install anti-collision train technology, federally mandated work that the agency says will be completed over six months instead of a projected 12-month project if executed with a weekends-only schedule.
Regular rail service will operate between the line's Wachusett Station terminus and the Littleton station, a span that includes stops in Fitchburg, North Leominster, Shirley and Ayer.
The T said the bus service will be in place until Friday, May 2. An express shuttle will operate between Alewife, South Acton and Littleton stations.
As part of service cutbacks, the T eliminated weekend service on the Fitchburg line.