The walking beam oil pump is typical of North American designs in use since the 1920s. It includes a detailed stationary diesel power plant, walking beam, rear crank and counterweight, along with the odd-shaped "horse head" front counterweight that gives the machines their nickname. Designed from the ground up to be a working model, the kit includes provisions for a hidden drive with the motor under your layout surface. Whenever you're ready, just add the Universal Gearbox and Motor Drive Kit 933-1050, sold separately, to power your pump. Complete instructions and precise engineering produce a great looking, easy to build replica. As shown the Walking Beam-Horse-Head Oil Pump measures: 2-3/4 x 1 x 1-13/16" 6.8 x 2.5 x 4.5cm The Walking Beam-Horse-Head Oil Pump is just one of a wide variety of Cornerstone N Scale industrial structures and accessories.