b. The bolts. The strength and
tightness of the bolts securing the bars to
the rail contribute greatly to the efficiency of
the rail joint. The bolts used to splice light
rail are either 7/8 or 1 inch in diameter;
those for heavy rail, 1 1/4 inches. Typical
bolts, shown in figure 3.18A and 3.18B, have
either hexagonal or square nuts, and the
boltheads are either hexagonal or square.
Figure 3.18C shows one type of spring lock
washer that is placed between the nut and
the bar, to prevent the nut from working
loose. The section of the bolt directly under
the head is oval. Alternate holes in the bar
are also oval while the remainder are round.
When the oval section of the bolt is fitted
into the oval bolthole, the bolt is prevented
from turning because of jarring or vibration.
The oval holes also serve another
Figure 3.18. Typical Rail Joint Bolts, Nuts,
purpose. Rails, 75 pounds and up, are bolted
and Spring Lock Washer.
so that the nuts alternate
between the inside and outside of the rail. Looking at the outside of the rail, for example, you
would see a bolthead, a nut, a bolthead, and a nut; looking at the inside, you would see the
opposite sequence. The sketch given here views a
rail joint from above; R indicates round hole; O,
oval.
You may ask, Why are the bolts staggered? They
are
staggered for a good reason: the wheel rim of a
derailed
car
could shear off all the nuts if they were all
installed on one side. To insure, then, that the bolts will be staggered when installed, the bars
are manufactured with the alternate round and oval holes and the bolts are made with the oval
neck section. For low rail and that
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