This odd looking Maintenance of Way device is known as a flanger. A type of snowplow used to clear packed snow or ice that accumulates between the rails. They could also be used to spread ballast. Compressed air supplied from the locomotive is used to raise and lower the blades which is controlled by the engine crew from the locomotive cab. The target signal at the top indicates whether the blade is up or down. It is supplemented with a lantern for night operations. D&RGW number OC was built in 1885 at their Burnham Shops in Denver. Most of its life was spent on the Cumbres Pass between Alamosa and Durango. Of the eleven that were constructed only three have been scrapped. OC was purchased by the Colorado Railroad Museum in 1971.