Rotary OY is a narrow-gauge steam rotary snowplow built in 1923 by the American Locomotive Company for the Denver & Rio Grande Western.
The machine entered service decades after OM and represented a later generation of rotary-plow construction.
Its steam engine powers the massive front cutting wheel while separate locomotives provide forward movement.
OY worked the Rio Grande narrow-gauge system in mountain snow territory where deep drifts could make ordinary plowing ineffective.
The plow survived the 1970 transfer of the Antonito–Chama line and equipment to Colorado and New Mexico.
Cumbres & Toltec used OY in several preservation-era snow-clearing demonstrations, including full-route work across the pass.
By the late 1990s the plow was no longer in active operating condition and remained out of service for more than two decades.
Friends volunteers and railroad shop crews undertook substantial structural, boiler, and mechanical work beginning ahead of the railroad’s fiftieth anniversary.
OY returned to operation in February 2020 during a special winter event, its first use in more than twenty years.
For TransitSatellite, OY should be presented as a maintenance-of-way system rather than a standalone attraction: pusher locomotives, crew coordination, visibility, snow depth, and water supply all determine how the rotary can work.