noun / verb
rail
RAYL/reɪl/
A long rigid bar forming part of a structure.
A sturdy metal rail beside the steps provides support.

Etymology
Latin regula named a straight piece of wood—the basic shape behind a rail. The bar used between supports also came to name the metal bars that support and guide railway wheels.
In context
… initially rail sections are welded together and transported through the tunnels sleepers are then positioned beneath providing a stable base followed by the placement of rail Steel on top the track is secured …
More examples
- The fence has three wooden rails between each pair of posts.
- Steel rails guide the train's wheels along the track.
- Workers rail off the edge of the platform for safety.
Forms
rail · rails · railed · railing
railing noun — A barrier made of connected rails.