the other. Note in figure 2.15 that the lever is placed so that it is parallel to the track. As the lever is operated,
the movable rails slide away from their accompanying stock rails a minimum of 4 3/4 inches; however, the throw
can bc adjusted from 4 1/2 to 5 1/2 inches. When the lever is thrown back to the original latch, the movable rails
again slide back against the stock rails. Look again at figures 2.3 and 2.4. Figure 2.3 shows a split switch closed
for main-line movement, and figure 2.4 shows it thrown for turnout.
Turnouts make it possible for a train to leave one track and enter another. A turnout is a combination of
five components: a switch, a frog, guard rails, closure rails, and switch ties. A turnout is either left- or right-
handed. The sharpness of a turnout is determined by the acuteness of the frog angle.
The two designs of switches are stub and split. Although economical and adaptable to light, slow traffic,
the stub switch is quite unsafe and difficult to maintain. Its rails are connected by tie rods, and both of the main-
line rails move. The split, or point, switch is more common than the stub switch and is safer and more
satisfactory. Split-switch rails are fastened to crossties. In the split switch, one main-line and one turnout rail
A frog is installed at the intersection of the running rails, to provide a channel for the wheel flanges to
move from one rail to the other and to provide a continuous bearing for the tread of the wheel. A frog has a toe, a
throat, and a heel, and both an actual and a theoretical point--all of which are names of its parts. Both spring and
rigid frogs are manufactured. Rigid frogs are of three types: bolted-rigid--the military standard, hard-centered,
and manganese steel. Regardless of direction, a train going through a turnout has its wheels, on one side or the
other, pass through the frog. Facing and trailing-point movements describe the directions the train travels
through the turnout.
Two guard rails are installed opposite the frog, one on the main-line side and the other on the turnout
side. Closure, or lead, rails connect the switch rails to the frog. These in turn are joined by switch rods so that
the switch rails can be moved as a unit.
The two stock rails, one bent and the other straight, are the ones that the switch points beat against. The
bent stock rail is curved at the theoretical point of the switch to protect the switch