trunk line

a major long-distance transportation line.

Origin of trunk line

First recorded in 1850–55

National participation, however, should be confined to trunk-line systems.

State of the Union Addresses of Calvin Coolidge |Calvin Coolidge
Before the panic of 1857 the trunk-line railways had completed their net of tracks between the Mississippi and tidewater.

The New Nation |Frederic L. Paxson
It now looks as if they were the only way through for a majority of the trunk-line railroads.

The Railroad Problem |Edward Hungerford
As far back as the early fifties this great work of rebuilding the trunk-line railroads was begun.

The Modern Railroad |Edward Hungerford

The seven vertical rows of keys, immediately to the right of the three trunk-line rows, are the line keys.

Cyclopedia of Telephony and Telegraphy, Vol. 2 |Kempster Miller

trunk line

a direct link between two telephone exchanges or switchboards that are a considerable distance apart

the main route or routes on a railway