Geared steam locomotive
This gearing is part of the machinery within the locomotive and should not be confused with the pinion that propels a rack locomotive along the rack between the rails. The geared steam locomotives that have been built have been for conventional track, relying on the adhesion between wheels and rail.
Johnson Bar (locomotive)
The reversing lever in locomotive history is documented from about 1842. The American Railway Master Mechanic's Association had members that published illustrations. Parts for the reversing lever are drawn in the "Locomotive Dictionary", 1st edition (1906), by George Little Fowler. The lever is linked to the valve gear piston inside the high pressure steam port. The steam pressure faucet is closed to cut off power, and after coming to a halt, the valve gear piston could safely be moved a short distance using the lever as a fulcrum linked to the piston inside. Although the linkage was designed to give leverage, the Johnson Bar would take a firm throw to move and lock in position. Some locomotives had a screw reversing gear instead.