Ton mile

[Sarah]

A unit of measurement of the freight transportation performedby a railroad during a given period, usually a year, the total ofwhich consists of the sum of the products obtained by multiplying theaggregate weight of each shipment in tons during the given period bythe number of miles for which it is carried.

[Kai]

The product of the distance that freight is hauled, measured in miles, and the weight of the cargo being hauled, measured in tons. Thus, moving one ton for one mile generates one ton mile.