The D-dock system consists of a D-dock Test Block which is put between the existing relay socket and the existing D-U plug-in relay. All 14 relay-pins are wired to the Break-Out Box enabling to connect measuring equipment like multimeters, scope meters or data analyzers to log operations during longer period. This makes fault finding easy. The D-dock fits in tightly packed relay panels and small cabinets.  It can operate unattended enabling normal passenger operating service.


To diagnose during operation random and repetitive failures in train systems. In depot, the failure does not occur or cannot be repeated and currently, during operation there is no possibility to perform electrical tests due to the presence of passengers. As a result, the fleet performance suffers from random and repetitive failures longer than desired.


  • Non-intrusive system, the train system remains fully functional
  • Monitoring relay operation: voltage and current per relay contact and coil
    No special tools required
  • Suitable for unattended multi-day monitoring and data storage (no more than one week)
  • Compact design to fit in tight train cabinets
  • Suitable for any D-relay type (D-Dock) or A/B-relay type (B-Dock)




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