Reducing Drag for the Rail Industry.

Reducing drag for the rail industry. A short video by Dr Kevin Linfield, P.E.

This video is brought to you by Airflow Sciences Corporation. For all your flow modeling and testing needs, since 1975.

Open top bulk commodity carriers, such as gondola or hopper cars carrying coal or ore experience high drag when traveling back to the mine. This drag increases fuel usage, resulting in higher operational costs and more greenhouse emissions.

The dynamics of open-top rail cars and the impact of aerodynamic modifications on train fuel usage can be investigated via wind tunnel testing, computer simulations, full scale over-the-track testing, and engineering handbook calculations. Input parameters are broad, and may include information on the locomotives, the number of cars in the train, car type, details of the train route, and train speed histograms.

The shape of the top of the car plays a very important role in how the air enters, swirls, and exits the empty cavity.

By calculating the forces exerted on the car and analyzing the leading and trailing edges, the drag of the car can be determined and often straight-forward geometry changes can result in a noticeable reduction of drag.

Aerodynamic airfoils can be attached to the top, horizontal corners of the empty car end walls. The additional structure is dependent on the gondola or hopper rail car geometry, but generally features a curved front surface and a large radius tail attached to the front and rear inner walls.

Airflow Sciences recently investigated fuel savings on long trains traveling over hundreds of miles. Handbook calculations determined that an expected fuel savings of about 7% could be achieved. Computational Fluid Dynamics (CFD) modeling combined with wind tunnel testing predicted a 15% decrease in the drag on the train by implementing geometry changes, including an "airfoil" shape.

For more information on reducing drag, please visit www.airflowsciences.com

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Copyright Airflow Sciences Corporation. With content provided by Jim Paul, P.E. and Dr. Kevin Linfield, P.Eng., P.E.