The plow at the Illinois RR Museum was intact when it got to Kansas City. After a few years the UP came calling with a request for the feedwater pump and other parts to use on the 8444. Since the plow was never going to run again the museum gave up the parts. I don't remember what they got in return.

I have no first hand experience with the snowplows. I can say that a Shay exhaust blurs into a solid roar fairly quickly. I suspect that the same would be true of the plow, especially with two engines. Just a roar, sort of like a jet engine.

The Swiss built some six cylinder self propelled rotary plows with 0-6-6-0 running gear. See here:

http://www.hazegray.org/rail/snow/rotary/steam01.jpg

Thinking of the many Shays I have heard run I agree that the Lima plows probably made a continues roar.

Branford Electric Rwy. Ass'n. - Shore Line Trolley Museum has Montreal Tramways
self propelled electric rotary plow 5. We do not realize that we must have it pushed
if it is also going to plow snow.

Talking about steam or diesel rotaries, of course.

Using Google image search I found a view of the business end of the Montreal Plow at Shore Line on this webpage.

Also using Google I found this page with a couple of electric rotaries on the Rhode Island Company - United Electric Railway. Go about two-thirds the way down the page. The double-truck car seems to have the same kind of rotary as the Montreal car.

And here is a page about the equipment of the Southern New York Railway. About one-third the way down the page is yet another self-powered electric with the same kind of rotary as the Montreal car.

Also I found this page (reproducing a newsletter) of the New York Museum of Transportation. It shows a couple of different electric railway rotary plows.

I would think that if the snow is still fresh and not too deep, it should be easy for a self-powered car to push into it and use the rotary.

If it's fresh and not too deep, you wouldn't need a rotary in the first place.

I'm talking about snow 6 feet deep or more, that has been packed down by wind and fills
cuts from end to end.

Six? How about fifteen? I'm more familiar with the use of rotaries on the western plains, where the use of multiple locomotives was not so much for pushing power, but "drag out" service after the plow became bogged down and stuck from snow collapsing against the sides.

The electric rotaries seem to have a somewhat different function; moving the snow further away from the track, much the same reason they used sweepers rather than plows on city streets. It's not the same as railroad service at all.

The National Park service at Mt Rainier uses what is essentially the world's largest snowblower on the roads. It's not a rotary, it uses the same type of mechanism you see on the ones you can buy at Home Depot to clear your driveway, only this thing is like 8 feet tall. They also use them in other locations, this just happens to be the one I've seen personally.

It is, of course, self propelled. It is also much smaller than a railroad rotary. It looks roughly like a combine harvester.

If this thing can propel itself up and down the side of a mountain while plowing snow, I fail to see why a rail mounted version, with room for an even larger engine, couldn't do the same?

As per my message above, it's not pushing into the snow that's the problem, it's getting stuck when the walls of snow collapse against, and under, the machine. A rubber tired machine can make multiple thrusts to "nibble" at a particularly large drift from different angles, an option the railroads didn't have.

The Soo Line had a hard time with snow on the northern plains. The wind would pack the cuts level full, sometimes fifteen or twenty feet deep, well over the roof of the plows. The snow was rock hard, and often contained frozen cattle carcasses where the animals had tried to find shelter from the wind. According to the late Jim Welton, who was a trainmaster on the territory during the forties and fifties, the technique was to push the rotary in, pull it out, push it in, until it wouldn't push any more, then pull it out and drill deep holes in the snow face with hand augers, insert dynamite, blast the snow down, then run the rotary in again. There was always a danger of getting stuck in the slot. Often they'd be accompanied with an extra locomotive that wasn't even used to push; it was the "drag out" loco, the purpose of which was to keep from having to dig the outfit out by hand.

Interesting this thread earlier mentioned Soo X-19, the big rotary the Soo purchased after the war, which ended up seeing very little use. After a tumultuous time during the Great Depression and war years, the Soo was finally returning to profitability. Along with money for the new rotary, there was also increasing funds for MOW work. Mechanized earth moving, of the sort that was to build the Interstate Highway system, had become a lot cheaper than it had been when grading was done with teams of horses. The road began a program of widening cuts, cutting the side walls down to a gentle slope. With this change, instead of packing the cut full of snow, the wind tended to blow them clean, and really lessened the the amount of snow fighting that needed to be done. Thus the big rotary became surplus.