This was a township owned narrow gauge tractor which used the drawbar for summer maint and front mounted snow plow in the winter. The snowplow was hydraulic with a hand pump which I had many strokes on both as a kid and operator. Summer use became limited when a Motor Grader was bought, but the grader couldn't handle the snow. The RD6 was retired another 10 years later with the purchase of a D6-8U.
These pictures were taken in the later 1950's and 1960 in NW Illinois.
This is a Cat similar to what KoO mentions "STERLING'S SUNKEN CATERPILLAR RD6 WINTER FREIGHTING CAT".