Wheel-rail impact interaction on the high-speed railroad bridges

The paper describes interaction of high-speed rolling stock and railroad bridge deck and proves the importance of adequate model of wheel (mechanism) and rail (structure) interaction. The model must consist of a rail and slabs of the ballastless deck. The paper characterizes the results of computer simulation of perspective rolling stock passing through high speed railroad bridge, that contains the uniform bridge superstructure for Moscow – Kazan line. The paper shows that in case of resonant bridge superstructure vibration the risk of derailment is high because of the decline of the wheel-rail contact force down to zero, which means wheel uplift. Moreover, the impact of the wheel is the result of uplift and the impact value is similar to the impact from impossible damages of wheels or rail on high speed railroad in consequence of which rail breaking occur. This rail breaking is the most frequent reason of derailment. The impact forces are equivalent to the impact of the fresh flat of the wheel and may be more than 300 kN while static force is equal to 85 kN. The vertical contact force is rising from zero to maximum value for 0.002 to 0.004 s after uplift. The computer simulation results show that it is the bridge superstructure resonance, which leads to impact interaction. The rail fasteners rigidity decline causes vertical interaction force decrease during the impact but the derailment risk still exists during vibration of “bridge – track – train” system.