Passenger service on the Shawmut Branch ended on September 6, 1926 to allow the Boston Elevated Railway to construct its rapid transit Dorchester Extension to Ashmont.
Construction on a high-speed trolley line from Ashmont to Mattapan began in early 1929, and the line opened as far as Milton on August 26, 1929.
The high-speed trolley line entered the center of the Milton branch right of way on a flyover, and ran to Milton flanked by the Milton branch tracks.
Commuter rail service ended when the trolley line reached Milton, over the protests of Milton residents who wanted limited service kept while the trolley line was extended to Mattapan.
After four more months of construction, the full trolley line was opened to Mattapan on December 21, 1929.

In 1930, the Boston Transit Department authorized the construction of an infill station at Butler Street, at an estimated cost of $13,695, to serve the small adjacent neighborhood.
Butler Street station opened on October 7, 1931.
Uniquely on the line, the station was built with a single center island platform rather than two side platforms; this was necessary because freight service continued on the Milton branch, which bracketed the trolley tracks.
A footbridge spanned both freight and trolley tracks, with a set of stairs leading to the station platform, which was covered by a canopy.
The freight house remained in use by the New Haven Railroad.

In the early 1980s, the station was rebuilt.
The pedestrian bridge was removed and a grade crossing built for platform access; the outer parts also served as small side platforms.
An awkward gable roof was added to the old canopy supports.

The MBTA closed the line on June 24, 2006 to allow a new viaduct to be constructed at Ashmont station.
During the closure, all stations on the line were modernized and (except for Valley Road) made accessible.
Butler station received a new platform and canopy, with a wooden ramp for accessibility.
Trolley service resumed on December 22, 2007.
Passenger service on the Shawmut Branch ended on September 6, 1926 to allow the Boston Elevated Railway to construct its rapid transit Dorchester Extension to Ashmont. Construction on a high-speed trolley line from Ashmont to Mattapan began in early 1929, and the line opened as far as Milton on August 26, 1929. The high-speed trolley line entered the center of the Milton branch right of way on a flyover, and ran to Milton flanked by the Milton branch tracks. Commuter rail service ended when the trolley line reached Milton, over the protests of Milton residents who wanted limited service kept while the trolley line was extended to Mattapan. After four more months of construction, the full trolley line was opened to Mattapan on December 21, 1929.
In 1930, the Boston Transit Department authorized the construction of an infill station at Butler Street, at an estimated cost of $13,695, to serve the small adjacent neighborhood. Butler Street station opened on October 7, 1931. Uniquely on the line, the station was built with a single center island platform rather than two side platforms; this was necessary because freight service continued on the Milton branch, which bracketed the trolley tracks. A footbridge spanned both freight and trolley tracks, with a set of stairs leading to the station platform, which was covered by a canopy. The freight house remained in use by the New Haven Railroad.
In the early 1980s, the station was rebuilt. The pedestrian bridge was removed and a grade crossing built for platform access; the outer parts also served as small side platforms. An awkward gable roof was added to the old canopy supports.
The MBTA closed the line on June 24, 2006 to allow a new viaduct to be constructed at Ashmont station. During the closure, all stations on the line were modernized and (except for Valley Road) made accessible. Butler station received a new platform and canopy, with a wooden ramp for accessibility. Trolley service resumed on December 22, 2007.
Butler station (MBTA)