tonnemiles

Tonemiles, often written as ton-miles or tonne-miles, are a unit used in freight and transport to quantify the amount of goods moved over a distance. It represents the movement of one ton of freight by one mile. The term is commonly used in North American rail and trucking analyses, as well as in logistics reporting, to measure overall freight activity and productivity.

There are two common variants: short ton-miles, based on the US short ton (2000 pounds) and miles, and tonne-miles, based on the metric tonne (1000 kg) and kilometers. In practice, organizations may specify the exact definition they use, and international reporting often favors tonne-kilometers to align with metric standards. For cross-border comparisons, converting between these forms is necessary.

Usage examples include calculating total freight throughput, evaluating energy efficiency, or comparing routes and carriers. For instance, moving 5,000 short tons over 300 miles amounts to 1,500,000 ton-miles. When converting to metric units, 1 short ton-mile is roughly 1.46 tonne-kilometers.

Limitations of tonemiles include a lack of information about cargo value, density, or hazard classification, and potential confusion from differing definitions (short tons vs. metric tonnes). Because it does not account for cargo characteristics, tonemiles are often complemented by other metrics, such as tonnage, tonne-kilometers, or value-based measures, to provide a fuller picture of freight activity.

History and usage context: The unit emerged in the mid-20th century within North American freight analysis and remains widespread in rail and logistics, even though it is not an official SI unit.