Rack-driven mining machine with pivotal guide shoe

In a mining machine of the type which moves along a track provided with a gear rack and wherein a driven gear on the machine engages the rack to move the machine along the track, the improvement comprising a skid bearing upon and guided by said rack, the skid being pivotally connected to said mining machine intermediate the ends of the skid about an axis extending transverse to the path of travel of the machine, and a gearwheel fixedly mounted on said mining machine and meshing with said gear rack whereby rotation of the gearhweel will cause the machine to traverse the track, the axis of rotation of the gearwheel lying in a substantially vertical plane through which the pivotal axis of said skid extends whereby pivotal movement of the skid with respect to its pivotal connection to the mining machine will not affect the meshing engagement of the gearwheel with said gear rack.