3.17. PRESERVATION
According to one estimate, tie renewals cost two to three times as much as rail
replacements. To reduce this expense, several practices are followed to extend the life of the
ties, to pre-vent their decay, and to deter their cracking and splitting. Probably the most
important of these is the widespread use of ties that have been treated with a chemical
preservative. Other practices include using antisplitting irons, stacking ties in certain ways, and
placing the heartwood side of ties on the ballast.
a. Chemical treatment. Have you ever wondered why wooden ties are so black? The
answer is simply that these ties were creosoted before being put into service, to prolong their life
and to prevent decay. One commercial railroad reports that creosoting extends tie life 10 to 30
years. Care must be taken in handling the creosoted ties; creosote can burn bare skin and cause a
rash similar to poison ivy. When handling them, gloves must be worn, and the outside of the
gloves must not be allowed to touch anyone's skin.
Creosoting is the most extensively used process for preserving ties; zinc chloride
is used in another. But whichever process is used, adequate distribution of the preservative and
thorough penetration of the wood are essential.
Although military railroads at stateside installations use treated ties for their
economic advantage, military railroad operations in a theater would probably not extend over a
period long enough to warrant preservative treatment of new ties. The military track supervisor
in a theater should inspect a rail line early in its operation and, if it is laid with untreated ties, he
must anticipate the need for frequent replacements.
Before ties are placed in
service, they must be adzed and any needed
spike holes bored. Adzing consists of
planing away only enough wood to provide
a smooth, satisfactory seat for the rail or tie
plate. See figure 3.4. All adzing and boring
must be done before the tie is treated with a
chemical preservative. Cutting or boring
after treatment might result in exposing
untreated
Figure 3.4. Adzed Crosstie.
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