I'm going to guess that THIS is in fact what you are looking for/talking about?
http://www.railroad.net/articles/railfa ... WF0012.jpg
The picture previously posted appears to be a ca. early 1900s Russell, not the same beast as the one in the link above which MEC (and B&A, and numerous othe nortehrn new enaglnd RR's ) had.
Based on text and a drawing in one of Bill Gove's NH logging RR books that idnicated plows o fthis design were built by the Portland Co. for a couple of the NH logging railroads, and that the maine 2-footers bought much equipment from the Portland Co., I would hazard the guess that these were built by the Portland Company, which was located next to the GT yard on the Portland waterfront and in it's day, late 1800s-early 1900s, built many cars and locomotives for northern New Engalnd's railroads. I dont; know when they started building plows of this design, but I'd guess they didn't build any after about 1910. Incredibly, photos exist (such as the one I linked above, which even without the caption stating "1965", we know must be later than ca. 1960 because the large block "MEC" lettering did not ecist prior to that timeframe) that show them still around in the 1960s on the MEC. I believe at least one o fthe 2 ft gauge plows exists at one of the museums?