The line originally had four tracks to Riverside station (two curved to the south and are currently used by the MBTA's Green Line D branchlight rail service). The number of tracks running into downtown Boston was reduced to two in the 1950s, in order to build the Massachusetts Turnpike, which parallels the easternmost ten miles of trackage, although CSX retains the original Boston and Albany Railroad trackage rights.
The Boston and Worcester Railroad opened its line from Boston west to Worcester in 1834 and 1835.[3][4] The Western Railroad opened from Worcester west to Springfield in 1839.[5] The line became part of the Boston and Albany Railroad, New York Central, and Conrail through leases, mergers, and takeovers, and was assigned to CSX in the 1999 breakup of Conrail.
The state took over ownership of the line between Worcester and Boston in 2012, and took over dispatching in 2013.[6]