TM 55-203
Crossbearer. A transverse member of the underframe,
as a pivot. The body center plate or male center
placed between the bolsters, which acts as a tie
plate is attached to the underside of the body
between the various sills and helps to distribute the
bolster, or, in cast-steel bolsters, is made an integral
weight of the cars.
part of the casting. The female or truck center plate
is attached to the top side of, or cast integral with,
Designations. Facing the B end of the car, in their order
the truck bolster.
on the right side of the car, wheels, journal boxes,
and contained parts (excluding box lids) are known
Center sill. The central longitudinal member of the
as R1, R2, R3, and R4, and similarly, those on the
underframe of a car. This sill forms the backbone of
left side of the car are known as L1, L2, L3, and L4.
the underframe.
The same order of numbers is used for designating
Centrifugal dirt collector. A device connected in the
corresponding locations of brake beams.
branch pipe between the brake pipe and distributing
Dome cover.
The closure for the top of a tank car
valve or triple valve and so connected that owing to
dome.
the combined action of centrifugal force and gravity,
dirt and foreign material are automatically
Draft gear. That unit which forms the connection
eliminated from the air flowing through the collector
between the coupler rigging and the center sill. The
chamber. By means of a plug, the dirt thus
purpose of this unit is to receive the shocks
collected may be removed without breaking any
incidental to train movements and coupling of cars
pipe connections whatever
and so spread out the force of impact that the
maximum unit stress is brought within the capacity
of the car structure.
capacity brakes to enable changing from "empty" to
"load" brake. Check valve (triple valve). The valve
Draft gear attachments. The parts which connect the
under the emergency valve which prevents brake
coupler and the draft gear.
cylinder pressure from escaping back into the
trainline when a hose bursts or the train parts.
Draft gear pocket. The space occupied by the draft gear
and followers in the center of draft sills.
Composite. Made up of distinct parts of elements.
Draft lug. One of a set of stops riveted, bolted, or
Coupler (car). The device by means of which cars can
welded to the draft sills and transmitting to them the
be automatically connected and disconnected.
stresses received from the draft gear.
Coupler head. The portion of the coupler which houses
Dust collector (airbrake). A device for preventing dust
the coupling mechanism.
or pipe scale from passing to an airbrake valve
mechanism.
Coupler horn. The projecting lug cast on the head of the
coupler which bears on the striking plate when the
Dust guard. An ordinary dust guard may be a thin piece
draft gear is closed solid.
of wood, leather, felt, asbestos, or other material
inserted in the dust chamber at the back of a journal
Coupler-knuckle lock. The block which drops into
box. The dust guard fits closely around the dust
position when the knuckle closes and holds it in
guard bearing of the axle.
place, preventing uncoupling.
Elliptic spring. A spring shaped like an ellipse and
Coupler lock lifter. The part of the mechanism inside the
composed of two sets of parallel steel plates, called
coupler head which is moved by the uncoupling rod
leaves, of constantly decreasing length.
Such
and in moving lifts the knuckle lock so that the
springs generally are used for bolster springs for
knuckle can open.
passenger cars.
Coupler shank. The portion of the coupler behind the
Emergency reservoir.
A reservoir for storage of
coupler head.
compressed air to operate the brakes of individual
Coupler yoke. The yoke or strap that surrounds the draft
cars in an emergency application.
gear and is keyed or riveted to the end of the
Empty
and
load
brake
equipment
(freight).
coupler shank. Also called draft yoke.
Equipment which gives, automatically, practically
Cover plate. In the metal underframe of cars, a plate
uniform braking power whether loaded or empty.
which is riveted or welded to the flanges of the
End sill. The transverse member of the underframe of a
center sills to give them additional vertical strength
car, extended across the ends of all the longitudinal
as in a box girder. The plate riveted to the top
sills.
flanges is called a top cover plate and the one
riveted to the bottom flanges, a bottom cover plate.
Glossary 3
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