may not restrict yard work greatly, one with a high density of
traffic may delay yard operations to the extent that it would be
advantageous to relocate the main track.
b. Divided leads. A desirable arrangement is to have divided
leads at each end of a yard. This enables two yard crews to work at
the same time. Where only a single lead exists and two crews are
employed, one crew generally couples cars and makes room on tracks,
while the other uses the lead in switching cars.
c. . Running tracks. Usually extending the entire length of the
yard, running tracks provide a route of travel to any point in the
yard independent of the switching leads and classification tracks.
Such an arrangement is shown in figure 1.1. When two running tracks
exist, they are assigned directional designations such as eastbound
and westbound. Most railroads permit road and yard crews to use
these tracks without prior yardmaster permission, provided their
movement is in the direction specified by the track designator. With
the exception of yard facility tracks, discussed in paragraph 1.6,
running tracks are generally the only ones that may be used without
getting permission from the yardmaster.
d. Long leads and approaches. Providing access, by switching
crews, to any track within a yard, switching leads must be of
sufficient length to accommodate the cuts or drafts of cars normally
handled in the particular yard. They also lead out of the yard to
running tracks or to the main line. Long approaches to the switching
leads are desirable so that yard crews can move long cuts of cars
from one track to another.
e. Track length. Tracks should be long enough to accommodate
inbound and outbound trains without doubling, or moving cars off one
track and coupling to cars on another. If a 100car train enters a
yard on a track capable of holding only 65 cars, it is necessary to
double 35 cars to another track and to block the lead while making
the double. This frequently delays yard crews switching cars on the
lead. If an outbound train is built up on two or more tracks of
limited length, delay will occur in doubling the train. On the other
hand, when the train is on one track, the air test, which can be made
only after the train is complete, is made before the train moves out
to block the lead. Furthermore, pusher engines may be used to help
reduce the delay by pushing the train out of the yard.