Geared steam locomotive
A geared steam locomotive is a type of steam locomotive which uses gearing, usually reduction gearing, in the drivetrain, as opposed to the common directly driven design.
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.