The power of the traction engine is transmitted to the traction wheels
by a series of gearing, all of which should be made from accurately cut
patterns to insure the teeth meshing perfectly to prevent them from
cutting and grinding out, and of sufficient strength to withstand the
very rough usage to which they are subjected. The gearing of an engine
should never be run without first greasing them thoroughly with a good
quality of solid oil or axle grease, for if once you allow the teeth to
cut, it will be impossible to stop them from cutting, the result being
they will soon be ruined. The gearing on traction engines are placed
in many different positions for transmitting the power to the traction
wheels, as will be seen by examining the different illustrations given
in this book.
On a side gear engine the power is transmitted from a small pinion
on the main shaft to an intermediate gear, from this gear to the
differential gear on cross shaft which is placed under the cylindrical
part of the boiler against the fire box. To this shaft are keyed two
small pinions at each end, which mesh in large spur gears fastened
securely to the traction wheels.
On a rear gear engine the power is transmitted from the small pinion
on crank shaft to large spur gear attached to one end of cross shaft,
which crosses the boiler at the rear end. To the other end of this
shaft is attached a small pinion that meshes in the large differential
gear which is attached to traction wheel and main axle.