Chapter 2
WHEELS AND AXLES
2.1. INTRODUCTION
The variety of rail car superstructures is numbered by the hundreds; however, the parts making up a piece
of rolling stock are basically the same in every type of car. Starting from the rails and building upward, the first
stop is, of course, at the wheels. Next in order are the axles and then the joining or mating of two wheels with
each axle. A separate section is devoted to each of these, in the order mentioned.
Section I. Wheels
2.2. GENERAL
Probably the most important single development in the history of technology is the wheel. Transportation,
particularly modern transportation, was built around the wheel, and it wasn't until the advent of rocket
propulsion that it began to assume a secondary role. Of all the specialized wheels ever developed, none has
ever approached the tonnage-movement capability of the freight-car wheel. When you listen to the sounds of a
speeding train and hear the high singing voice of its wheels riding twin ribbons of steel, you can in no way deny
the urgent feeling of power in motion. The special wheel used on railway cars carries food from the world's
bread baskets, feeds raw materials to the hungry mouths of industry, and distributes industrial byproducts to the
ever-increasing, ever-expanding world market: an instrument of peace and prosperity. The railroad wheel has
also been used for making war. Each time it has become militarized, it has carried out its mission of rolling
troops and supplies to where they were needed. When you, as a transportation officer, become involved with
this highly special railroad wheel, it will most probably be used in time of war. You will need to know
something about it: how it is made, what can go wrong with it, how much it can be used, and how to determine
when its work is finished. These things are explained in this section.
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