Relay groups represent the basic functional elements of the railway signalling and safety system. The devices are standardized according to the function they perform and include:
- Signal groups
- Point (switch) groups
- Track circuit groups
- Track balise groups
- Interlocking dependency groups
- Level crossing barrier groups
- Dependency groups with automatic block system (APB)
Each group is designed to perform a precisely defined function within the railway traffic safety system.
Construction and Installation
Each type of relay group is installed on a predefined relay frame, in a precisely designated and coded slot.
Relay groups are of a plug-in type, enabling simple installation and maintenance.
On the front side, they are protected by a glass panel from external influences, while still allowing visual inspection of the group status.
A single relay group can accommodate up to 35 relays of type K-50.
All relay groups are:
- technically tested
- certified
- sealed
System Safety Logic
The system is designed according to the “fail-safe” principle.
In the event of any disturbance — such as wire contact or interruption, voltage breakdown, component damage, or improper relay operation — the signal automatically switches to the “stop” aspect, and the system transitions to its safest state.
All commands, controls, and interdependencies are executed through the relay equipment, ensuring complete system control and operational safety.
