In 1912, the PV&T purchased 10 cab-forward mallets to help get trains over the Green Mountains in Vermont. The Green Mountain subdivision isn’t terribly heavily graded (ruling grade is about 1.5%) but has some moderately long tunnels at the crest of the ramps, so the PV&T followed the lead of the Southern Pacific and ordered 10 4-6-6-2 machines from MLW.

These engines were quite successful, but only lasted about 8 years on the Green Mountain subdivision before the railroad was electrified out from under them. They then went to the Montréal mainline (featuring the Mount Cube Incline) and hauled trains between Portland & Montréal for another decade until that mainline was finally electrified, and finished off their careers as pool power on the B&Q’s international line between Ville Québec & Augusta.

The last one was retired in 1948; none survive.