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Computer-based Interlocking System(VPI)

VPI is the computer-based interlocking system with independent fail-safe check module and NISAL technology based on the common dual system hot-standby structure, and realizes dual system parallel control. The NISAL technology adopts the operation principle combining the CPU (CPU/PD1) board used for interlocking calculation with the independent VPS board to make sure high system safety. The corresponding technology has passed the European SIL4 safety certification, making VPI the only interlocking equipment whose core safety technology has passed the international safety assessment among China’s dual system hot-standby computer-based interlocking systems. The interlocking function, system reliability, maintainability, loading capacity and anti-interference capability of VPI system all conform with relevant standards of MOR as well as actual requirements of the site. The system is equipped with interfaces of on-site simulation test and ex-works test. Also the lightening protection capability and EMC of both software and hardware of the system have passed the test of MOR.

System Advantages

  • VPI applies ALSTOM’s multiple safety-assurance core technologies which have been certified in Europe and are widely used in computer-based interlocking, on-board and ground ATC systems.
  • VPI adopts the safety system design technologies which can be programmed such as NISAL technology, I/O port independent different check-word dynamic test in 50ms cycle, independent timer, double channels different software, inherent fail-safe, composite fail-safe and reactive fail-safe to guarantee the system safety.
  • The system applies redundant technologies such as collection sharing and paralleled output control by dual systems to improve the reliability of the system.
  • With ex-works simulation test interface, the interlocking computers can run special test software and select hardware test interface on the SDM so as to conduct tests to automatically or manually check the wiring of interlocking computers and their input or output codes.
  • With electronic guide diagnostic functions, VPI is easy for maintenance and diagnosis.
  • VPI is designed with embedded on-site simulation test interface and vital check-out or check-in design of simulation test data is involved in application software. When the system is upgraded or under daily check, one set of equipment can be upgraded and tested while the other maintains uninterrupted running so that the upgrade of the whole station and the test of interlocking function can be completed without affecting the normal operation.
Open Interlocking Design Technology
  • The open interlocking design CAD software package developed for the VPI system simplifies the station interlocking design and upgrade and realizes real-time safety analysis of each internal parameter.
  • This technology is essential to carry out safety check, safety test and safety evaluation of the interlocking software if the station needs to be usually upgraded under tight schedule. It is also an important foundation of the third-party independent safety assessment which often appears in international bidding projects.

Case Study

  • Nigeria’s Abuja-Kaduna Railway

    Abuja-Kaduna Railway is the first modern railway in Nigeria even in West Africa,
    which all used Chinese technology and standard. It is an important part of 
    modernization in Nigeria’s railway.

    Casco provided the core of signaling system for all the nine stations
    —VPI computer interlocking system.

  • Ejina-Hami Railway

    Ejina-Hami Railway is the key project of China’s “One Belt and One Road” 
    Strategy and mid-long term railway planning.

    Casco provided multiple signaling system products like FZk-CTC, VPI and CSM-KA.

  • Honghai Station in Guangzhou-Shenzhen Railway

    The first computer-based interlocking system for 
    main line in China’s railway