Abstract
This paper is a study of the coupler pressures, car speeds and accelerations in a long train, produced by external forces acting on same.
It is based on the similarity in behavior of such a train and of an elastic bar of the same length as the train, the same mass per unit length and the same yield, when subjected to longitudinal compressive or tensile forces.
Following the method explained in the paper, the pressure and speed diagrams are derived for the various periods through which the waves are passing, the beginning and ending of each period being marked by certain events. Formulas are derived for the maximum bar pressures and tensions, for the locations at which they occur, and for the maximum accelerations or retardations of the particles.
It is shown how these formulas may be applied to freight trains of known characteristics, and the general requirements are derived which should be met by a freight-car draft gear under given service conditions.
Well-known elementary calculations, based on the official ARA Draft Gear Tests and supplemented by the formulas given in the paper, permit the design of draft gears suitable for the given service conditions.
