铁路运输是关系国民生计的大事，能否正常而不被中断，关系到社会的各个方面。而现阶段大部分的轨道电路故障都是由于轨道的绝缘破损造成的，由于铁路线路点多线长的特点，对于轨道绝缘的检修和维护是一项非常繁杂与艰巨的任务，因此对轨道绝缘是否破损的判断和预防显得非常重要，不仅要使得检测的结果准确，还要使得检测的速率高效。 目前铁路电务系统对轨道绝缘的测量通过肉眼观察和万用表极性交叉法相结合来判断轨道绝缘是否破损，此方法不但效率低下而且误判率特别高，完全不能满足目前我国铁路高速发展的要求，跟不上铁路发展的步伐。所以急需开发一款能够快速准确测量轨道绝缘状态的手持仪器来满足铁路电务系统的测量要求；并且这款测试仪能够在不中断铁路运输的条件下实现在线测量，并对铁路轨道电路不产生任何影响。 本文的主要目的是设计一款能快速在线测量轨道绝缘性能的仪器。主要设计思路是：先由一个信号发射器向轨道绝缘的两端被检测处发射一个高频脉动恒流信号，然后采集轨道绝缘两端反馈信号，通过测试仪内部的DSP处理电路，进行FFT变换分析，滤除牵引电流回流及轨道各种频率信号，分离出能够表征绝缘电阻变化的信号分量来，计算高频脉冲恒流信号在轨道绝缘节上产生的阻抗值，以此判断轨道绝缘性是否良好。试验表明轨道绝缘在线测试仪达到了预期的效果，能够快速准确测量轨道上各种绝缘阻值，减轻了铁路电务人员的工作强度，提高了工作效率，具有一定的应用前景。

Railway transportation is a great event related to the livelihood of the people. If it does not work normally, it will affect every aspect of the society. Now the most failures of the track circuit are caused by the insulation failure of the track. Because of the complex characteristics of railway lines, the maintenance of track insulation is a very complicated and arduous task, and it is also important to judge and prevent the damage of track insulation. The detection result must be accurate, and the detection rate is also highly efficient. At present, the measurement of rail insulation is based on the combination of naked eye observation and the polarity interleaving method of multimeter to determine whether the track insulation is damaged. This method is not only inefficient but also has high misjudgment rate, which can not meet the requirements of high-speed development of China's railways at present. So it is urgent to develop a handheld instrument that can measure the insulation status of track quickly and accurately to meet the measurement requirements of railway electric system. The tester can realize online measurement without interruption of railway transportation, and it can not produce harmful effects on railway track circuit. The main purpose of this paper is to design an instrument that can measure the insulation of track quickly. The high frequency pulsating constant current signal is emitted to the track insulation detection section, and the feedback signal is collected. Through the DSP processing circuit inside the tester, the FFT transformation analysis filters out traction current reflux and various frequency signals, so the signal components, which can characterize the change of insulation resistance, are separated, and the impedance values of the high frequency pulse constant current signal inside the track insulation joint are calculated to judge the insulation of the track. The test shows that the track insulation on-line tester has achieved the expected effect. It can quickly and accurately measure all kinds of insulation resistance on the track, reduce the work intensity of railway personnel and improve the working efficiency, and it has a certain prospect of application.