- the foundation laid to support the ties, rails, and ballast of a railroad
- a layer of crushed rock, cinders, etc. immediately under the ties
- the foundation or surface of a road or highway
- a. The foundation upon which the ties, rails, and ballast of a railroad are laid.b. A layer of ballast directly under the ties.
- The foundation and surface of a road.
- The prepared location for a road, including its foundation.