Description: HOn3: 1/87 scale, 105mm gauge, 3 foot prototype. Denver and Rio Grande Western Derrick OP and idler car. OP was a light lifter mostly used in track maintenance and wreck clearance work, steam provided by an adjacent locomotive. Wood and whitemetal Rio Grande Models kit, but with many replacement parts, upgrades and extra details added. Note the scratchbuilt winch inside the house.