The Greenbush Line is a branch of the MBTA Commuter Rail system which serves the South Shore region of Massachusetts. The 27.6-mile (44.4 km) line (which shares 10 miles of trackage with the Old Colony Lines) runs from downtown Boston, Massachusetts through the towns of Braintree, Weymouth, Hingham, Cohasset, and Scituate to the Greenbush section in southern Scituate.