Some rails are joined together
by welding, but most rails are connected by means of a bolted
splice. There are usually two or three holes drilled in the
end of the rails for these splices. The hole spacing pattern
is called the "drilling" and is measured from the
end of the rail to the center of the first hole, and from the
center of the first hole to the center of the second hole, etc.
Thus a drilling might be 2-1/2" x 5" or 3-1/2"
x 6" x 6".
The standard drillings for
tee rails and corresponding splice bars provide for a 1/8"
gap between rail ends. Although this construction is satisfactory
for railroad track and light crane service, its use in general
crane service may lead to joint failure. For best service in
bolted splices, it is recommended that "tight joints"
be stipulated for all rails for crane service. Although tight
joints are not standard for tee rails, we can supply tight joint
in the ASCE sections from 30-lb to 85-lb.
The term "splice bar"
refers to only one type of connector and frequently is confused
with other types. The drawings below provide clarification of
the proper term for each type of connector bar.