lighter than 75 pounds, the bolts are applied with all the nuts to the outside of the track. To do
so prevents the nuts from being stuck, especially on worn rails, by the flanges of worn wheels.
A joint bar, when classified according to its cross section, falls into one of three
classifications: angle, head-free, or head-contact. The last two, so-called symmetrical bars, are
generally used on heavy rail, which, having greater height than lightweight rail, has more space
between its head and base. Unlike the angle bar, the symmetrical bars have no flanges; they are
large enough to provide sufficient stiffness without them. The more uniform shape of the
symmetrical bars offers greater resistance to stress. Details on the three types are given in the
subparagraphs following shown in figure 3.19.
Figure 3.19. Types of Rail Joint Assemblies.
a. A typical angle bar is easily identified by the large flange, or toe, at the bottom which
hides the rail base. An angle bar is the most desirable form of joint bar for use with small rail
having a limited distance between the head and flange (the fishing space); the extra metal in the
flange increases the bar's stiffness. Figure 3.19A pictures an angle bar joint assembly.
b. A head-free joint bar contacts the rail at the fillet curve between the head and web.
The arrows in figure 3.19B denote the points of contact in a typical assembly. This bar has a
greater area of contact with the rail than the head-contact type, discussed next, and thereby
permits heavier loads. Also, the head-free bar adjusts its fit with the rail more easily and with
less loss of bolt tension.