Rail gauge and rapid-transit train stability

The stability of a light-weight train against overturning in a crosswind has received only scant attention in the past. This study comprises a wind tunnel investigation and an analysis of the major static and dynamic forces that might combine to overturn a train either when running or when standing still. Results are shown in parametric form and indicate the trends to be expected if wind velocity, car weight, rail gauge, speed around a curve, and several other factors are varied. Since stability is almost linearly related to the product of car weight and rail gauge, it is essential to use a wider gauge when trains are made lighter, if stability is to be maintained.