Dynamic Characteristics of High Speed Vehicle Passing over Railway Turnout on Bridge

摘要

Based on principle of vehicle-track-bridge dynamic interaction, a dynamic simulation model of a high-speed electric multiple units (EMUs) passing over turnout on bridge was established. The calculation focused on 200km/h No.12 improved ballasted turnout(60kg/m rail) being laid on 3×32.0m simply supported beam, it analyze dynamic characteristics of a freight train with 25t axle load passing at speed of 120km/h and those of CRH1 EMUs passing at speed of 200km/h. Results show that: when the freight train passes the turnout through the main line, the vertical stiffness of the simply supported beams is not sufficient due to the relatively high speed and large axle load; when the EMUs passes the turnout on bridge, the dynamic deflection change rates of girders at the switch and frog are great and the turnout is not appropriately set on the bridge, so the frog crosses over the beam gap, which results in the increasing of track irregularity and finally causes derailment coefficient of vehicle to overrun to reduce the running safety; when a train passes the turnout zone on bridge, interaction between the vehicle and turnout is significant because of load fluctuation of the wheel caused by inevitable structural irregularity at the switch and nose rail, and this requires strengthening measurement and running within speed limit.