knew that a hostile unit were positioned so that it posed a threat to
rail operations in a certain area, you would select, if possible, a
rail line that would avoid that area.
After the primary rail lines have been selected, alternative
lines should be chosen, in case the others are cut by enemy action,
tied up by a railway accident, or impaired by washouts, landslides,
or floods.
1.3. TECHNICAL ASPECTS
Because operating a railway is a highly technical business, a
great deal of thought must be given to the technical aspects of
existing rail lines and facilities if rail operations are to be
successful. Some of the most important technical characteristics,
both desirable and undesirable, are described in the following
subparagraphs.
a. Classification of railways. Railways are classified according
to their gagethe distance between the heads of the parallel rails,
measured fiveeighthsinch below the top of the rails. This
measurement is shown by the broken line in the inserted sketch. The
general gage classifications are standard, broad, narrow, and meter.
Approximately 60 percent of the railway mileage in the world is
standard gage, 56 1/2 inches wide. Broadgage railways are 66, 63,
and 60 inches wide; narrowgage railways are 42 and 36 inches and
narrower widths; and metergage railways are 39 3/8 inches wide. For
defense, some countries construct railways with a different gage from
that used by neighboring countries. Rail equipment built for one
gage does not operate on other gages.
Track gages vary within a country or area, from country to
country, and from continent to continent; table I presents the track
gages found in principal countries and regions of the world.
b. Desirable physical characteristics. The railway system in a
theater of operations may be large enough and complex enough to
afford a choice of the part or parts to be used. Certain physical
characteristics are desirable and must be examined, because they
influence the decision in selecting one railroad instead of another.
(1) Adequate yards, terminals, and shop facilities. A railway
car normally spends at least 50 percent of its life in either
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