Dynamic Stability of Cars in Long Freight Trains

A method is described for investigating the lateral response and hunting tendency of cars in long trains. A linear model is developed representative of North American freight-car design with parameters descriptive of wheel wear and truck flexibility. Included is a simple model of the couplers assumed under tension. Transfer matrices are used to examine the behavior of groups of cars. Results are given showing that the behavior of a group of such cars under tension is no less stable than that of the single uncoupled car. The effects of variation in certain parameters on the natural response are described. Truck stiffness is shown to have a primary effect on the lateral stability of the car.