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Wednesday, July 31, 2019

What exactly is a Unit Train...?

Many people I know, who are model railroaders, say a unit train is a train consisting of a single type of car, tank cars, coal hoppers, grain hoppers, you get the idea. Although close, this isn't exactly true. One of the best explanations I've read is by a person named dehausman (sorry but that's all I have). It was presented on the Model Railroader Magazine forums in a discussion of mixed 50 and 70 ton hopper trains. He centers the explanation on coal hoppers but as you can guess it applies to all types of rolling stock.

By strictest definition then, what exactly is a Unit Train?

A unit train is a train billed on a multi-car waybill. It will have blocks of cars, typically 25-50-75-100-100+ cars all billed on a single waybill, which means all the cars on the waybill go from the same origin to the same destination. The multicar waybill did not become popular until the 1960's and 1970's.

Unit trains can have railroad owned cars or private cars. The cars can have a painted panel or not. There are standard steel hoppers, auto unloading hoppers, rotary gons, combination rotary and bottom dump hoppers. Standard hoppers can be bottom dumped or rotary dumped.

For a 1950's layout there would be coal trains, but not unit coal trains. There would be a 100 car coal train with 100 cars with 100 waybills, all of which could go to a different destination. On a unit train there would typically be 100 cars and one waybill.

The mix of cars depends on who the customers are for the coal. It was common for railroads to collect coal cars at a central yard and build solid coal trains to some destination where they would be switched and sent to the final destination. For example on the Erie it could be some major city. In the 1950s a city would use a lot of coal so the Erie might send 100 cars of coal to a city and the yard there would switch it up and put the coal cars on 10 different locals to be delivered to 40 different customers. Or the entire train could go to one customer such as a steel mill or a rail to water facility.

Seventy ton cars actually became popular in the 1920's. The PRR, B&O and NYC all had lots of 70 ton coal cars in the 20's and 30's (the PRR had more H21 hoppers than some other roads had cars of all types).

dehusman on MRR forums


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