Today most aggregates that move by railroad move in unit trains.

What is an aggregate unit train?

Today most aggregates that move by railroad move in unit trains.  Unit trains are groups of railcars (usually from 40 to 120 rail cars) that move as a solid train from a quarry to a unit train receiving yard.  The unit train will be powered by dedicated locomotives and crews.  These trains typically move from the quarry to the receiving yard in 24 to 48 hours and will make a round trip in slightly less than a week.

Why are unit trains efficient?

Unit trains are an efficient way to move rock over a railroad for several reasons:

History of Aggregate Unit Trains in Texas

Texas Crushed Stone and Georgetown Railroad pioneered the movement of aggregate by unit trains.
In 1976 Texas Crushed Stone joined the MKT Railroad and applied for the first unit train rates in Texas.  This application was opposed by other Texas Railroads and the rate application was denied.

In 1979 the unit train rates were approved in a second rate application.  Shortly after the unit train rates were approved for Texas Crushed Stone, Georgetown Railroad and MKT Railroad rates were deregulated.

The movement of unit trains of aggregates has been a common practice in Texas for the past thirty years. Starting in 2002 the Union Pacific started a program of “Rocktimization” in which incentive rates were placed in effect to encourage unit trains.

TCS Eureka Yard Houston, TX 1980’s

What facilities are necessary to ship and receive unit train?

In most cases, a unit train must be able to be picked up by the Class I rail carrier and moved to the destination without switching.  To make such a move, the Class I carriers must have passing tracks that will hold the unit train.  In addition, the destination receiving the unit train should have enough trackage to receive the whole train without switching.  This will require more than 5500 feet of open track at the destination.  Class I carriers prefer that unit train receiving yards have two switches and a loop track.

Hopper Car

Gondola Car


What role can Texas Crushed Stone and Georgetown Railroad play in launching a unit train?

Texas Crushed Stone, working in cooperation with the Georgetown Railroad, has the material, railcars (both hoppers and gondolas) and the necessary trackage to launch multiple unit trains of any size on a single day.  All that is required to launch an aggregate unit train from TCS/GRR is a phone call. Our facilities are in place and waiting for your call.

Because the Georgetown Railroad connects with both The Union Pacific Railroad (UP) and The Burlington Northern Santa Fe (BNSF); it is economical to ship unit trains to destinations on either railroad.

How unit trains are typically unloaded?

Aggregate unit trains can be made up of either bottom dump hoppers or gondola cars.  Hopper railcars must be moved over an unloading hopper or unloading trestle. Moving the train over the unloading point requires almost twice the trackage than a yard designed to receive gondola cars.

TCS Eureka Yard Unloading Trestle 1980’s

In recent years it has become very popular to unload gondola unit trains with hydraulic excavators which operate on top of the gondola cars. Several companies, such as Gulf Coast Limestone, have made a business of “contract unloading” of aggregate unit trains with top unload hydraulic excavators.

How many facilities are here in Texas and Louisiana to receive aggregate unit trains?

Approximately 30 unit train aggregate yards with capacities from 40 railcars to over 100 rail cars have already been built in Texas and Louisiana.  There are numerous unit train yards in the Houston area.

If you want a unit train of aggregate, call us and we will help you locate a nearby receiving yard.

What are the typical freight charges for aggregates moving in unit train service?

On a typical unit train move, the freight rate will depend on the number of railcars in the unit train.
Unit train pricing for both the Union Pacific and Burlington Northern Santa Fe can be found on their website.