Interlocking Systems Technology

Interlocking Systems Technology

  • Geographical interlocking
  • HR92 interlocking system (Hybrid)
  • HR97 interlocking system (Hybrid)
  • HR(S)

Geographical interlocking:
ACTOM has the facilities to manufacture, refurbish or upgrade any type of geographical interlocking system currently in use on any railway in the world.

Relay interlocking with our without automatic route setting:

  • ACTOM Transport has designed this system for small and medium sized stations.
  • Free-wired with either initiation elements or optional PLC control, this is an extremely cost effective signalling option.
  • The equipment is accommodated in kiosks and trackside housings, which eliminates the need for expensive buildings.
  • The system design is extremely flexible. Individual systems are tailor-made to customer specified requirements and signalling layouts.
  • N or C type composition UIC code 736I safety signalling relays are used for all vital functions.

HR92 Interlocking System (Hybrid):

  • ACTOM Transport can supply HR92 (Hybrid) geographically orientated interlocking systems, designed for medium sized stations.
  • The complete interlocking is function tested by simulation on an in-house developed system to provide realistic in-circuit simulation and addresses the full spectrum of the HR92 unit’s diverse capability.
  • Using advanced computer technology, the highest standard of quality assurance is maintained. All the basic units are functionally tested before they are shipped.

HR97 Interlocking System (Hybrid):

  • The HR97 hybrid relay (geographical oriented) interlocking system is based on the basic principals of HR92, differing in such that each removable unit is now a single unit utilising distributed I/O.
  • Functions such as emergency points and emergency signals are included in the design. The HR97 relay interlocking is designed for complex and large stations. The PLC communicates over a high-speed bus (World FIB), incorporating intelligent user-friendly diagnostics.


This simplified geographical relay based interlocking is designed and supplied by ACTOM Transport, as a cost effective solution for small stations. The design is based on the basic principals of the HR97, utilising the PLC for all the non-vital functions and the vital functions being performed over safety signalling relays.