2.1.
INTRODUCTION
One spring day in 1953, the "Colonial Express," arriving at Washington, D.C., after an
overnight run from Boston, suffered an airbrake failure and crashed through the bumping block
at the end of Union Station's track No. 16. The locomotive and first car arrived on the concrete
floor instead of alongside the platform. The concrete floor promptly collapsed, dropping the
equipment into the mailroom below. Yes, modern rail equipment is heavy.
Because the locomotive weighed 130 tons, it is not surprising the concrete floor gave way.
This incident illustrates the impact the forces involved in operating locomotives and trains can
have. If the track between Boston and Washington had been laid directly on the surface of the
ground instead of on an adequate roadbed, the 130-ton locomotive of the "Colonial Express"
would have caused the ground to give way in many places just as it did the concrete floor. The
rails of such track would bend or break in many places, speed would necessarily be cut, and
derailment would occur often.
To add to these problems, rain would frequently cause the tracks to be covered with
water, and the resulting mud would offer no resistance to the weight of trains. Furthermore, the
ground surface is irregular. Track laid directly on such an irregular surface would result in an
extremely rough ride as well as damage to rolling stock, freight, and rails. Operation over such
track would be a nuisance and an economic failure.
An adequate roadbed is essential to a stable track, because it must provide the proper
foundation for the trains rolling over the track. The ballast used on it must be of the correct
composition and depth, and the roadbed must be well drained. Chapter 2 contains two sections.
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