Operated by the Canadian National Railway (CN), the M&SCRC ran trams on tracks in the street in Montreal and closer South Shore communities, and on separate right of way in rural areas.

The Montreal and Southern Counties Railway Company was established through an act of Canadian Parliament on June 29, 1897, with a mandate to "lay out, construct and operate, by electricity or any other mechanical power except steam, a railway [...] from a point in or near the northern limit of the county of Chambly [...] to a point in or near the city of Sherbrooke.

"[7] In spring 1909, M&SC laid tracks along Riverside, Mill, Common, Grey Nun and Youville Streets in Montreal.

In 1911 a southern branch was built from the foot of the Victoria bridge, to link St. Lambert to the Ranelagh Country Club and opened on Labour Day "to accommodate golfers."

That branch was then continued east through Greenfield Park and Mackayville, junctioning with the GTR main line to St. Hyacinthe.

[11] In 1913 work began to electrify the Central Vermont Railway line between the GTR junction northeast of Mackayville and Marieville.

Interurban service expanded rapidly along this existing track:[12] The Company came to a ten-year agreement with town of Granby to run trains on its Main Street (now rue Principale).

Service to Abbotsford and Granby finally opened on April 30, 1916, with a workshop at the corner of Main and Pie-IX Boulevard.

A bypass to the CN station in Granby was built and the original Main Street track was discontinued.

[27] Throughout the 1930s the railway lost money, but its importance as a means of transportation during the war years ensured that the company remained a going concern.

CN replaced the service with three daily diesel-powered trains from Waterloo through Granby and Marieville, along the former railway's track until the junction to the St. Hyacinthe subdivision where it would go directly to Montreal's Central Station.

[33] This change coincided with the end of passenger service between Waterloo and Montreal through Granby, Farnham and Saint-Jean-sur-Richelieu.

[35] Service over the Victoria Bridge between St. Lambert and Montreal was stopped on June 15, 1955 as part of the Saint Lawrence Seaway construction.

[39] Interurban trains took the same tracks as the suburban streetcars, up the Greenfield Park/Mackayville branch up to a right of way operated by Vermont Central Railway.

[41] Instead of rolling down urban streets, and to avoid the weight limits on the shoulder of the Victoria Bridge, freight trains could connect to the rest of the Canadian National Railway network at a junction in Southwark rail yards (along today's Route 116 between Vieux-Longueuil and Saint-Hubert).

[47] Interurban trains would stop in a yard behind the building, between Youville and Common (rue de la Commune) streets.

Suburban cars would circle on Grey Nuns (rue des Soeurs-Grises), Youville and McGill streets.

Though many Anglophones left these neighbourhoods following the election of the Parti Québécois in 1976 and the referendum on sovereignty in 1980, their legacy can be found in the names of boroughs (Greenfield Park) and streets (i.a.

[62] Today, much of the rail line's right-of-way has since been converted into cycling paths, including La Route des champs, a span of about 40 kilometres between Marieville and Granby.

[63] La Montée du Chemin Chambly,[64] a part of Route Verte 1 and the Trans Canada Trail, follows the path of the railway between the borough of Saint-Hubert in Longueuil and the city of Carignan.