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A railroad tie is a rectangular object used as a base for railroad tracks. Traditionally, ties have been made of wood, often heavily creosoted or, less often, treated with other preservatives.
Ties are laid on top of sand, gravel or heavy crushed stone
- called track ballast. They are laid across the grade at
intervals of about two feet. The steel rails are then laid
atop the ties, perpendicular to them. With wood ties, cleats
are laid down and spikes driven through them into the ties
to clamp down the rails. The rails are held on wooden ties
with rail spikes. After this is done, additional ballast is
then added to fill the spaces between and around the ties to
anchor them in place.
The ties then act as anchors and spacers for the rails,
while providing a slight amount of give to accommodate
weather and settling. The ties are "floating" in the top of
the ballast. Failure of a single tie is generally
insignificant to the usability and safety of the rails. A typical mile of rail contains approximately 3,000 ties.
In recent years, wooden railroad ties have also become very popular for gardening and landscaping, both in creating retaining walls and raised-bed gardens, and sometimes for building steps as well.
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