Experimental tests and numerical simulations of railway vehicles at low speed in derailment conditions

International audienceThis article is dedicated to the derailment phenomena, applied to two real cases in sharp curves. The multibody method is used to simulate the dynamic of two types of trains in the VOCOLIN environment. The first vehicle concerned is a metro passing in a turnout located between two tight curves. Only simulations are exposed, the semi-Hertzian method is used to describe the turnout. The second one is a special industrial vehicle with four wheelset bogies passing in a tight curve. In this case the contact is modelled by a multi-Hertzian method. The L/V ratio is calculated by simulations, measured by tests and compared with Nadal's criterion. The vertical force V is measured indirectly by deflections of the primary suspensions which stiffnesses are known. The lateral force L is estimated by a new method, the deflection of the wheelset