Figure 3.2. Side Frame.
Because of the important function of the journal box and the inspections and maintenance it requires, it is
discussed in a separate paragraph.
3.5. JOURNAL BOX
The axle journal, discussed in the preceding chapter, is housed in the journal box. A typical journal box
with solid friction bearing is shown in figure 3.3. The box has three principal functions: it distributes the weight
of the car and lading evenly over the journal, provides for continuous lubrication of the journal, and dissipates
heat generated within it. Each part of the journal box is explained in the following subparagraphs.
a. The dust guard and plug are inserted in a vertical slot in the back end of the box. The plug fits closely
with the turned axle dust-guard seat to prevent dust, cinders, dirt, or moisture from entering the box from the
rear. The dust guard and plug are inserted into the slot before the journal is fitted into the box.
b. The journal friction bearing is cast in a contour to match the axle journal. It is made of bronze, brass, or
special iron and is set on top of the journal. The journal bearing has a babbitt-metal
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