DRAFT FORCES. The force on a draw bar that tends to pull on a draw bar. Draft forces tend
to pull the train apart.
DRAFT SYSTEM. The term used to describe the arrangement on a railcar for transmitting
coupler forces to the center sill. On standard railcars, the draft system includes the coupler, yoke,
draft gear, follower, draft key, draft lugs, and draft sill. On cushioned cars, either hydraulic
end-of-car cushion units and their attachments replace the draft gear and yoke at each end; or a
hydraulically controlled sliding center sill is installed as an integral part of the car underframe.
DRAWBAR. The coupler head and shank.
END OF TRAIN DEVICE (EOT). A device that contains a flashing end of train marker.
ENGINE. A mechanism for converting the energy in steam, air, or other gas under pressure into
mechanical energy in the form of motion, i.e., steam engine, diesel engine, gasoline engine.
FEED VALVE. A valve, which automatically maintains a predetermined pressure of air,
supplied through the brake valve to the automatic brake system.
FIXED SIGNAL. A signal of fixed location indicating a condition affecting the movement of a
train or locomotive.
FLANGEWAY. The open way through a track structure which provides a passageway for
FRICTION BEARING. (See BEARING.)
FROG. A track structure used at the intersection of two running rails to provide support for
wheels and passageways for their flanges, thus permitting wheels on either rail to cross the other.
FULL SERVICE APPLICATION. Manipulation made by the engineer on the automatic brake
valve handle so that auxiliary reservoir pressure and brake cylinder pressure is equalized. Full
service application is the largest reduction of reservoir pressure that can be made without applying
the emergency braking. Full service application is 26 lbs. for 90 lbs. of brake pipe pressure.
GLAD HAND. The metal fitting attached to the free end of each air hose. Glad hands are
designed to provide for quick and positive connection of air hoses on adjacent cars.
GRADE (horizontal). Horizontal track curvature expressed either in degrees or radii (feet).
The amount of central angle subtended by a chord of 100 feet.
GRADE (vertical). The percentage of change in track elevation to the level distance traversed.
One percent grade is equal to a change in elevation of one foot for each 100 feet of track.
GRADE CROSSING. (See CROSSING, HIGHWAY).
GUARD RAIL. A rail or other structure laid parallel with the running rails of a track to prevent
wheels from being derailed; or to hold wheels in correct alignment to prevent their flanges from
striking the points of turnout or crossing frogs or the points of switches.