What is a Unit Train?

CREX 1518 on the tail end of an oil train.
CREX 1518 on the tail end of an oil train.

Railway fans often mention “unit trains” when they are talking about trains they have seen. What’s a unit train?


A unit train is a freight train carrying a single commodity from a point of origin to a destination without switching cars en route.


A unit train of sand cars

Common unit train types include:

  • Crude oil trains
  • Frac sand trains
  • Grain trains
  • Auto trains
  • Potash trains
  • Lumber trains

What’s NOT a Unit Train?

The opposite of a unit train is called a “manifest” train, which is a train made up of cars with different origins, destinations, or car types. This is the general train you can see with boxcars, hopper cars, tank cars, flat cars, and so forth.

Passenger trains are not unit trains because they don’t carry freight, and they have multiple origins and destinations (every station stop).

Container trains are usually not considered unit trains, because they often switch cars in and out en route.

Union Pacific has a handy infographic about unit trains.

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