The railroad industry is responsible for the mass transport of a vast numbers of goods throughout the United States. As needs and capabilities of the railroad industry have changed, the interest in reducing the resistance of locomotives and railcars has increased. This has become paramount as fuel prices have increased in recent years. Resistant forces can result from friction in mechanical components and aerodynamic drag of the moving train. As the average traveling speeds of trains have increased, aerodynamics are contributing a larger fraction of the overall resistance. For this reason, the aerodynamic profiles of trains have become a topic of research. Furthermore, current manufacturing practices of railcars provide an opportunity for research in modifications that reduce the aerodynamic drag. This thesis reports on research that has been done to reduce aerodynamic drag on automobile-carrying railcars. Data was collected by placing G-scale (1/29) models into a wind tunnel with a 0.74 m^2 test section. These models were tested for Reynolds Numbers ranging from approximately 2.05 x 10^5 to 2.79 x 10^5. Modifications were made to the models with the intention of reducing the drag. The profile features of the auto-carrying railcars were reviewed and three regions were chosen to be the focus of this study. The selected regions are the roof, side panels and structural chassis region. Special attention was given to the regulations of the railroad industry to ensure the tested modifications would be candidates for implementation. From the data, it was determined that drag could be reduced by modifying or covering the roof, side panels and chassis structure by nominally 20%, 5% and 15% respectively.



College and Department

Ira A. Fulton College of Engineering and Technology; Mechanical Engineering



Date Submitted


Document Type





aerodynamics, railcars, train, wind tunnel