
Forgotten, but not obsolete.
Solid steel plows, snow throwers, flangers, snow melters, snow blowers powered by jet engines all exist and some are deployed every winter across the globe, yet the rotary snowplows still outperform the competition in both power-to-efficiency and spectacular snow removal nominations. Several reasons for the forgotten part: advent of more ubiquitous service and construction vehicles like bulldozers and the sheer maintenance cost of a single unit - even if it isn't actively used, just stored. Of course there are disadvantages too.- Rotary snowplows are more susceptible to debris (rocks, trees, etc.) found in the snow slides resulting from avalanches.
- Rotaries leave an open-cut that fixed-blade plows cannot push snow past, and so once rotaries have been used, they must be used for the remainder of the season, until the snowpack - multiple layers of compacted snow - has melted. Often deployed when snow is too deep or hard-packed for traditional plows though, the rotary's ability to operate slowly, as there is no requirement for train momentum to break up the snow, is often an advantage in mountainous regions, where a high speed derailment could be disastrous.
- Rotaries are also less used on routes with axle load restriction - with a weaker bridge along the way for example.


The most powerful piece of snowfighting equipment ever devised
Our inspiration came from the units SPMW 207 and SPMW 209 assigned to Union Pacific Railroad's Roseville Subdivision, California - both Leslie Rotary Plows, they were originally built with steam power and rebuilt during the 1950s to power the blade assembly by diesel locomotive traction motors. Today they are regularly sent out to move the "Sierra Cement" snow found on the Donner Pass Line. They get their electrical power from separate EMD F7B units, that were repurposed to power the rotaries, and themselves don't have traction motors. The F7B units are known as "snails" (this is derived from the fact that engineless but motored units that take their power from another locomotive are "slugs"; thus the opposite, with engine but no motors, is a "snail.") These plows are equipped with a Vapor-Clarkson steam generator too - handy for heat, cleaning ice out of the wheel and off the antennas, as well as blowing the steam whistle :)
