自全路开始全面推广使用ZPW-2000A制式电码化以来,采用二线制的车站约占50%左右,二线制电码化制式配套使用交流工频轨道电路的占有相当大比例。由于当时推广使用ZPW-2000A制式电码化时,绝大部分车站是在既有轨道电路的基础上利旧改造施工的,导致轨道电路的启用时间早于电码化设备。目前,这一部分车站轨道设备已陆续到大修期限,还有一些车站要在大修期到来前进行电气化改造,且由于97型25 Hz相敏轨道电路在 Since the whole road began to fully promote the use of ZPW-2000A standard code since the use of two-wire system stations account for about 50%, two-line system supporting the use of code-frequency AC frequency track circuit occupies a large proportion. Since the promotion of the use of ZPW-2000A standard code at that time, the vast majority of stations were rebuilt on the basis of the existing track circuits and lead to the opening of track circuits earlier than that of the digitized devices. At present, this part of the railway station equipment has been gradually overhaul period, there are a number of stations to electrification before the arrival of the overhaul, and the 97-type 25 Hz phase-sensitive track circuit in