Main track is laid with heavier, taller rail on deeper ballast than yard or branch trackage, and railroaders call it the high iron. The phrase carries some pride: crews on through freights run the high iron, while yard crews and branch-line locals work the lighter track. Getting out on the high iron means finally leaving the terminal and making miles.
Took us four hours to get out of the yard, but once we hit the high iron it was clear signals all the way to Cheyenne.
Also heard as
- main line
- the main
Related terms
Main line
The principal track or tracks of a railroad between terminals, where trains need authority to run.
Siding
A track alongside the main line, connected at both ends, where trains meet or let others pass.
Highball
A signal or radio call meaning proceed at full speed, and the verb for leaving or running fast.
Spur
A short dead-end track branching off to serve an industry or to store cars.