道岔和无缝线路长轨条焊联 ,当轨温变化时 ,长钢轨的纵向温度力将直接作用于道岔 ,引起导轨、心轨的伸缩。因尖轨跟端与基本轨通过限位器或间隔铁连接 ,导轨、心轨与基本轨间又通过扣件、岔枕等联结零件相连 ,导轨与基本轨之间的相互作用 ,导致岔区钢轨纵向力的变化。采用建立在导轨、心轨与基本轨相互作用基础上的纵向力计算方法 ,对 3 8号无缝道岔纵向力进行了计算分析。在京秦线 3 8号无缝道岔试验段 ,测定了不同温差情况下无缝道岔纵向力 ,现场试验表明 ,理论分析结果与实测结果基本一致 Longitudinal rail welded joints of turnouts and seamless lines, when the rail temperature changes, the long rail longitudinal temperature force will be directly on the turnout, causing rail, heart rail expansion. Due to the tip rail and the end of the basic rail through the stopper or interval iron connection, rail, the heart rail and the basic rail through the fasteners, switch ties and other connected components, the rail and the interaction between the basic rail, leading to fork zone Longitudinal force of rail changes. Based on the calculation of the longitudinal force based on the interaction between the guide rail, the center rail and the basic rail, the longitudinal force of the 38 # turnout is calculated and analyzed. In the test section of No.88 seamless turnout on Beijing-Qinhuangdao line, the longitudinal force of the seamless turnout with different temperature difference was measured. The field test shows that the theoretical analysis results are in good agreement with the measured results