The reverse centrifugal thrust in curves with small radius

In order to increase lateral track resistance on curves the «DINTRA» sleeper was created. This sleeper prototype increases the transverse stiffness in railway curves. During the field validation test of the «DINTRA» sleeper on a railway curve of a track section from the North of Spain, the evolution of the transverse displacement of the railway track and the longitudinal deformation of the rails were monitored. In the course of the field test, a structural phenomenon was detected. There is a transverse displacement of the rails to the inside of the curve. The authors have named «Reverse Centrifugal Thrust in railway curves». This article tries to explain and quantify this observed phenomenon. Authors propose two formulations: first (a) a formulation to determine the temperature increase experienced in the rails that delimits the structural phenomenon of Inverse Centrifugal Thrust, and then (b) a formulation to determine the transverse displacement in railway curves as trains pass under conditions of restricted thermal expansion.