[3][4] The line served as the route for Boston to Montreal service during the Golden Age of Rail (roughly 1880 to 1940).

[5] This line, along with the New Englander, via Concord, White River Junction, Montpelier, ran through the northwestern section of Vermont prior to entering Quebec, Canada.

The Alouette and Red Wing trains travelled to Montreal via Concord, Plymouth, Wells River and Newport in northeastern Vermont prior to entering Quebec.

Massive cutbacks on May 18, 1958, included the end of Stoneham Branch service and the closure of Medford Hillside, Tufts College, and North Somerville stations.

Boston–Lowell local service was halved to seven daily round trips; Tyngsboro, Bleachery, and South Wilmington stations were closed.

[10] Anderson Regional Transportation Center opened on April 28, 2001, replacing Mishawum as the Lowell Line's primary park-and-ride station for Route 128.

[11] The line was shut down on weekends in July through September 2017 for the installation of Positive Train Control equipment in order to meet a 2020 federal deadline.

[20] From May 20 to September 29, 2024, weekday midday inbound Haverhill Line trains were temporarily routed over the Wildcat Branch during construction work, again stopping only at Anderson/Woburn.

[9] MBTA Commuter Rail service connecting Concord, Manchester and Nashua from the Lowell Line used to exist in New Hampshire until subsidies were ceased in 1967.

[10] In October 2010, the New Hampshire Department of Transportation received a $2.24 million federal grant to study an extension of the Lowell Line to Concord.

[24] In January 2011, a bill was introduced into the New Hampshire legislature to end the proposed extension and give up a potential $4.1 million grant into its planning.

[28][29] Proponents of the extension see expanded rail services as a link to Boston’s growing economy while opponents consider the project to be extraneous and expensive.

[34] By autumn 2022, the study was being carried out by AECOM and the State of New Hampshire to design and make a financial plan for the project by 2023.

Additional speed restrictions are in place at Wilmington, through the grade crossings in West Medford, and in the North Station terminal area.