English: Animation showing a simplified "walking" mechanism, according to the 1926 Martinson patent, of a walking dragline. Side view on the left, front view on the right. The boom and dragline, which would extend out to the left, has been omitted. The orange axle, which is fixed relative to the body of the dragline, turns an eccentric green cam. The green cam's motion is constrained by the red leg and a purple pin which is free to move vertically in a slot on the leg. The orange axle is placed along the body of the dragline away from the center of gravity, towards the boom side of the dragline, so the body will tilt when it is raised.