护轮轨
排障器

Rail \Rail\, n. [Akin to LG. & Sw. regel bar, bolt, G. riegel a
rail, bar, or bolt, OHG. rigil, rigel, bar, bolt, and
possibly to E. row a line.]
1. A bar of timber or metal, usually horizontal or nearly so,
extending from one post or support to another, as in
fences, balustrades, staircases, etc.

2. (Arch.) A horizontal piece in a frame or paneling. See
Illust. of {Style}.

3. (Railroad) A bar of steel or iron, forming part of the
track on which the wheels roll. It is usually shaped with
reference to vertical strength, and is held in place by
chairs, splices, etc.

4. (Naut.)
(a) The stout, narrow plank that forms the top of the
bulwarks.
(b) The light, fencelike structures of wood or metal at
the break of the deck, and elsewhere where such
protection is needed.

5. A railroad as a means of transportation; as, to go by
rail; a place not accesible by rail.
[Webster 1913 Suppl.]

6. a railing.
[PJC]

{Rail fence}. See under {Fence}.

{Rail guard}.
(a) A device attached to the front of a locomotive on each
side for clearing the rail of obstructions.
(b) A guard rail. See under {Guard}.

{Rail joint} (Railroad), a splice connecting the adjacent
ends of rails, in distinction from a chair, which is
merely a seat. The two devices are sometimes united. Among
several hundred varieties, the fish joint is standard. See
{Fish joint}, under {Fish}.

{Rail train} (Iron & Steel Manuf.), a train of rolls in a
rolling mill, for making rails for railroads from blooms
or billets.