After the PV&T built from Parsons Vale to Portland, they set up their locomotive shops there. Other shops were built (Concord, Boston, and Schenectady) but the Portland shops remained the primary shops until the electrification reached the city of Portland in 1919 and all steam repairs were moved to the Boston and Concord shops. In 1946, the PV&T abandoned steam operation, closing the Concord and Boston shops (the Schenectady shops were used for freight car repair until 1984, then were closed in favor of the D&H’s Colonie shops), leaving the Portland shops as the only locomotive repair facility on the system.

The shops started producing entirely new motors in the 1960s when the PV&T wanted superpower class B’s and didn’t get an acceptable bid for them from General Electic.

When the shops started producing new motors they got a request to build a series of transfer motors from the Port of Montreal, so briefly went into business selling them. Alas, aside from the 4 units for the PdM, 3 units for the New York Central (delivered in 1967, juuust before the Penn Central merger) and 3 units for INCO, no North American railroad was in the mood to electrify, so that business went dormant in 1988 after selling a handful of class J units to the Canadian National and the Montpelier & Wells River. (These days the Portland Shops are too busy building and maintaining the Parsons Vale fleet to even consider going back into the business.)

However, in the 1990s, the PV&T wanted to experiment with radial trucks to see if they could improve pulling power on their curvy mountain routes without having to throw even more horsepower at the trains. Portland responded with the PRS (“Passive Radial System”, now known as the A4R truck), then followed up with the smaller B4R & B6R trucks for diesel electrics and motors that use bogies instead of an articulated underframe. All of these trucks have been licensed to ILW in Québec (though the A4R trucks are not used in any locomotive aside from motors that ILW builds for the Parsons Vale when the Portland shops are booked solid) which is offering them as an option under their eco class locomotives.