ZPW2000A non-isolation frequency-shift automatic blocking equipment is redeveloped on the base of the UM71 non-isolation track circuit technica, which is introduced and localized in China, in order to improve the security, transportability and the reliability of the system according to the situation of China.

Compare with the latter ZPW2000A has greatly improved the transmission security, transmission distance and the reliability of the track circuit, and raised the ratio of performance and the price, reduced the project cost.

The system research was began in 1998, and the improvement of the transmission site-test was carried in 1999, the site-test of the increase in track circuit transmission distance and the solution of the low resistance of the ballasts was carried in 2001, also in 2001 it passed the qualitative test, technical examination organized by the MOR. On 28^th May 2002, it passed the technical authentication of the MOR and was authorized to be widely used.

The system also can be used for the light railway and the metros;

1.       Affirming and keeping the superiority of the whole structure of the UM71 non-isolation track circuit;

2.       Resolving the inspection of the fracture of the steel rails in the tuning zones, realizing the inspection of the fracture of the steel rails in the whole course;

3.       Reducing the dead shunt zone in the tuning zones;

4.       Realizing the inspection of the breaking faults of the tuning units;

5.       Realizing the prevention to the interference of the beat frequency;

6.       Lengthening the transmission distance of the track circuit by optimizing the parameter of the system;

7.       Lengthening the track circuit¡¯s transmission distance of the mechanical insulating joints, realizing the track circuit¡¯s transmission distance in the same of the electronic insulating joints;

8.       The adjustment of the track circuit is carried according to the fixed track circuit length and the allowed minimum resistance of the ballasts, which is not only meet the request of the 1_¦¸¡¤km standard ballasts resistance and the transmission length of the low ballast resistance, but also improved the stability of the normal length track circuits;

9.       Using SPT railway digital cable made in China in stead of the ZCO3 cable made in France , which has reduced the diameter of the copper core ,and the spare cores, lengthened the transmission distance, and raised the ratio of the performance and the price , reduced the project cost;

10.   Using long sled bushing copper lead wire instead of 75mm² copper wire , which has made the system easy to maintain;

11.   The transmitter using ¡°N+1¡± redundancy, the receiver using two units working abreast , which has greatly improved the reliability of the system and excluding the influence of a single component¡¯s faults to the whole system.