Fast estimation of the derailment risk of a braking train in curves and turnouts

When a train runs through a turnout or a sharp curve, high lateral forces occur between the wheels and rails. These lateral forces increase when the couplers between the wagons are loaded in compression, i.e., a rear locomotive pushing a train or a front locomotive braking a train. This study quantifies these effects for a train that begins braking when steadily curving and for a train that brakes upon entering a turnout. Our approach allows distinguishing between the effects of braking and the transient effects of entering the turnout. The dynamic derailment quotient is mapped as a function of the vehicle speed and the braking effort. Then the dynamic derailment coefficient obtained from the dynamic simulations is compared to results from quasi statics. This allows determining a dynamic multiplication coefficient that can be used on the quasi static derailment coefficient to obtain a first estimate of the dynamic derailment coefficient.