turned crosswise or at right angles to the train line. When closed, the air pressure in the main line is stopped;
throughout a train, all angle cocks must be open except the one on the last car. An angle cock on the end of
each car is usually positioned between the flexible hose and the pipe on the train line. The handle locks in both
the opened and closed positions, and it must be raised slightly before it can be turned. This prevents the valve
from being accidentally opened or closed while the train is in operation.
c. The branch-pipe tee, or branch-line tee, is the joint at which the individual car airbraking apparatus is
connected to the train line.
d. The cut-out cock is a valve on the branch line that permits the car to be "cut out" of the train airbraking
system but still allows the flow of air through its train line to other cars farther to the rear of the train. This
valve is normally positioned on the side of the car beneath the side sill so that it is easily reached by trainmen.
When some part of the car's braking system is inoperative and the car is already coupled in a train, it is desirable
to cut this car from the train braking system. Regulations control the number of cars with inoperative brakes
that are permissible in a train. Table VI shows how many cars with inoperative brakes are permitted in trains of
various lengths.
e. The dirt collector, in the KC system, is connected in the branch line as near as possible to the KC triple
valve. In the AB system, it is combined with the cut-out cock and attached directly to the AB valve. The dirt
collector is designed to trap dust, pipe scale, and any other foreign matter that may be in the air lines; its bottom
part is removable for easy cleaning.
f. The triple valve has been discussed in previous paragraphs. It controls the flow of air to the various
parts of the car braking system by "recognizing" changes in air pressures.
g. The air reservoir on a railway car equipped with the KC airbrake is known as the auxiliary reservoir. It
was discussed previously. The air reservoir on a railway car equipped with the AB brake is a dual-compartment
reservoir. One side is the auxiliary reservoir that contains the compressed air supplied to the brake cylinder for
a normal service application of the brakes. The other side is the emergency reservoir that contains compressed
air for increasing the braking pressure in an emergency. The air charges and releases, to and from both of the
reservoirs, are controlled by the triple valve.
77
Previous Page
