Ladder Logic implementation for Romanian railway interlockings

Interlockings are critical systems for the railway network which ensure the safety of train operations. While previous generations of interlockings use hardware logic to implement safety functions, electronic interlockings employ different techniques and architectures to comply with strict reliability and redundancy standards. Ladder Logic has been used for decades for industrial automation, which has witnessed a transition from relay-based to PLC-based systems. This paper proposes a standard for translating relay interlocking schematics into Ladder programmes. The proposed model is evaluated against a physical relay interlocking.