B&M era The
Fitchburg Railroad began serving the town with a stop, located off of School Street east of
Main Street, when it reached the town on October 1, 1844. The railroad completed the first station in 1845 and, when the new station was built in 1892, the old station was moved to Jones Farm and used as a fire station until 1927. The station was reduced to a single agent in 1932. The building was used as a plumbing and electrical supply store by 1962, though tickets were still sold at the store. The
Boston and Maine Railroad sold the building in the early 1970s; it burned in 1984 and was torn down. The right-of-way has since been reused for the
Assabet River Rail Trail on its Hudson and Marlborough section. In 2018 rail trail construction will be completed on a 3.4 mile section starting at train station and extending southeast through Maynard to the Maynard/Stow border.
MBTA era The
Massachusetts Bay Transportation Authority was formed in August 1964 to subsidize suburban commuter rail service. On January 17, 1965, northside services were cut to the boundaries of the MBTA funding district. The Fitchburg Line was cut to until June 28, 1965 when it was reopened to . During that time, the line was known as the South Acton Line. Around 1977, the Town of Acton and the MBTA built a new platform two tenths of a mile westward, off of Central Street west of Main Street, to provide expanded on-site parking. The original parking lot is now the "overflow" parking lot; portions of the former platform remain in the brush off the north side of the tracks. The former station building was demolished between 1985 and 1995.
Fitchburg Line upgrades Until 2011, the main double-track section of the Fitchburg Line ended a quarter mile east of the station, with a short second under the Main Street bridge to allow a trainset to sit while preparing for an inbound run. The 1980s-constructed station had a single low platform, which was not handicapped accessible, serving the single track. As part of the ongoing upgrades to the Fitchburg Line infrastructure, South Action station was rebuilt and opened 2015, as the second track was added to the Acton-Ayer section of the line. The new station has separate platforms for inbound and outbound service; both platforms are full-length high-level for accessible boarding. They are connected by a pedestrian bridge which includes ADA-required elevators. A single-platform design was considered in 2009, but the imposing design and the need for large ramps were disliked by town residents. The two-platform design, accepted in 2010, eliminated the need for large ramps and allowed for Maple Street access. A small drop-off lane was built on the south side of the tracks off Maple Street, next to the new inbound platform. However, daily parking capacity was not immediately increased. On June 11, 2012, the MBTA opened bids for the $9.622 million construction project. Construction preparation began in September 2012. During the periods where the 1980s-built station platform was closed, temporary platforms east of the station (at the former station site) and west of the station were used to board passengers. The station site was prepared during the winter of 2012-2013, and work on the high-level inbound platform began in April 2013. Foundations for the inbound platform and the pedestrian bridge were laid in 2013. The subcontractor for the steel bridge structure was replaced due to compliance issues in 2013, delaying plans to have the project open by early 2015. The inbound platform was constructed in mid-2014, followed by the outbound platform in November 2014. Until 2014, South Acton was the only station other than Porter and North Station served by all Fitchburg Line trains, for a total of about 16 daily round trips. About one-third of these trips terminated at South Acton, while the others continued to Fitchburg. All
short turn trains were extended to Littleton/Route 495 station on August 4, 2014. The new station was largely complete by the end of November 2015 and opened on December 19, 2015. ==Service==