HO Rotary Snowplow & F7B Locomotive, ARR #3/#1503 Overview
The Rotary Snowplow is a piece of railroad snow removal equipment with a large circular set of blades on its front end that rotate to cut through the snow on the track ahead of it. When snow is too deep, the railroads call on their rotary. The precursor to the rotary snowplow was the wedge snowplow.
Early rotaries had steam engines inside their car bodies to power the blades. Rotaries of newer construction are either diesel- or electric-powered. Many steam plows were converted to electricity. Some electric plows can take their power from a locomotive, while others are semi-permanently coupled to power units
Some Rotaries get their electrical power from rebuilt F7B units, that were specifically rebuilt to power the Rotaries.