Aerodynamic drag reduction of goods trains

Abstract Tests on one-tenth scale hopper and gondola rail cars have been undertaken in a closed-circuit wind tunnel with a fixed floor. By varying the number of wagons in the train length, it was concluded that simulation of a typical wagon away from end effects (i.e. the influences of the locomotive(s) and trailing wagon) could be achieved with one and a half “dummy” wagons upstream and one half a “dummy” wagon downstream. An active model coupled to a drag balance was used to measure drag coefficients and drag reductions from geometric modifications on a typical wagon. The largest drag savings arose from fitting an enclosing top. Other effects, including inter-wagon gap and end fairings were also investigated. It was found that a practical wagon design, that was based on an existing wagon and allowed the current methods of loading and unloading, would reduce averaged drag coefficients by 27% for an unladen wagon. Considerably larger savings (up to 50%) could be made with more substantial wagon redesign.