In 1909, the Terminal de Montréal’s Pont Richelieu (on the Marieville branch, between Chambly & Richelieu) washed out, and instead of rebuilding the bridge arranged trackage rights from Chambly to just west of Marieville on the Montreal & Southern Counties’s Granby line. The M&SC was in the throes of electrifying this line, so the TdM followed their lead and also electrified the branch from the junction at Brossard east.

This electrification was followed by electrifying the line from Brossard to Delson, and then the Montréal-Est switching district.

When the PV&T started their mainline electrification in 1920, the TdM started electrifying their mainline south to the border with the same tension as the Canadian Northern’s Montréal to Deux-Montagnes suburban line. When the two electrifications finally joined together, the TdM upped the line from Brossard south to 3000vdc, and all further electrification was done at that tension.

The 600vdc lines continued pretty much unchanged for many years; Delson to Brossard was converted to 3000vdc during WW2, but Brossard to Marieville & Montréal-Est remained at 600vdc until 1958, when the Canadian National abandoned traction on the M&SC. At this point, Montréal-Est was reenergised at 3000vdc (by this time the old Canadian Northern suburban lines and the Port de Montréal electrification had also been retensioned at 3000vdc, so all the voltages matched) while the Marieville branch was dieselised.

Two of the original motors remained in TdM hands; #3, which was converted to a snowplough, and #5, which was stripped of its electrical components, and eventually found its way into ILW ownership, where it is now stored in ILW’s boiler shop.