What is "train mile"

Train \Train\, n. [F. train, OF. tra["i]n, trahin; cf. (for some of the senses) F. traine. See Train, v.]

1. That which draws along; especially, persuasion, artifice, or enticement; allurement. [Obs.] ``Now to my charms, and to my wily trains.''
   --Milton.

2. Hence, something tied to a lure to entice a hawk; also, a trap for an animal; a snare.
   --Halliwell.

   With cunning trains him to entrap un wares.
   --Spenser.

3. That which is drawn along in the rear of, or after, something; that which is in the hinder part or rear. Specifically :

   1. That part of a gown which trails behind the wearer.

   2. (Mil.) The after part of a gun carriage; the trail.

   3. The tail of a bird. ``The train steers their flights, and turns their bodies, like the rudder of ship.''
      --Ray.

4. A number of followers; a body of attendants; a retinue; a suite.

   The king's daughter with a lovely train.
   --Addison.

   My train are men of choice and rarest parts.
   --Shak.

5. A consecution or succession of connected things; a series. ``A train of happy sentiments.''
   --I. Watts.

   The train of ills our love would draw behind it.
   --Addison.

   Rivers now Stream and perpetual draw their humid train.
   --Milton.

   Other truths require a train of ideas placed in order.
   --Locke.

6. Regular method; process; course; order; as, things now in a train for settlement.

   If things were once in this train, . . . our duty would take root in our nature.
   --Swift.

7. The number of beats of a watch in any certain time.

8. A line of gunpowder laid to lead fire to a charge, mine, or the like.

9. A connected line of cars or carriages on a railroad; -- called also railroad train.

10. A heavy, long sleigh used in Canada for the transportation of merchandise, wood, and the like.

11. (Rolling Mill) A roll train; as, a 12-inch train.

12. (Mil.) The aggregation of men, animals, and vehicles which accompany an army or one of its subdivisions, and transport its baggage, ammunition, supplies, and reserve materials of all kinds.

    Roll train, or Train of rolls (Rolling Mill), a set of plain or grooved rolls for rolling metal into various forms by a series of consecutive operations.

    Train mile (Railroads), a unit employed in estimating running expenses, etc., being one of the total number of miles run by all the trains of a road, or system of roads, as within a given time, or for a given expenditure; -- called also mile run.

    Train of artillery, any number of cannon, mortars, etc., with the attendants and carriages which follow them into the field.
    --Campbell (Dict. Mil. Sci.).

    Train of mechanism, a series of moving pieces, as wheels and pinions, each of which is follower to that which drives it, and driver to that which follows it.

    Train road, a slight railway for small cars, -- used for construction, or in mining.

    Train tackle (Naut.), a tackle for running guns in and out.

    Syn: Cars.

    Usage: Train, Cars. At one time ``train'' meaning railroad train was also referred to in the U. S. by the phrase ``the cars''. In the 1913 dictionary the usage was described thus: ``Train is the word universally used in England with reference to railroad traveling; as, I came in the morning train. In the United States, the phrase the cars has been extensively introduced in the room of train; as, the cars are late; I came in the cars. The English expression is obviously more appropriate, and is prevailing more and more among Americans, to the exclusion of the cars.''

n. A unit used in estimate railway running expenses, etc.; one of the total number of miles run by all the trains of a road, or system of roads, as within a given time, or for a given expenditure.