EN 50121-4 Compliant Power for Railway Signalling Infrastructure
Railway signalling systems operate under conditions that few other electrical installations face: extreme temperature swings from -25°C to +70°C in un-conditioned trackside cabinets, continuous vibration from passing trains, electromagnetic interference from traction power systems, and a regulatory requirement that power must never be interrupted. When signals go dark, trains stop — and the economic and reputational cost of unscheduled railway downtime is measured in millions per hour.
PARWATT trackside UPS and power supply systems are purpose-built for railway signalling applications. Every unit is designed, tested, and certified to EN 50121-4 railway EMC standards, with wide-temperature operation, hardened enclosures, and communications interfaces compatible with both legacy relay-based and modern IP-based interlocking systems.
Engineered for the Trackside Environment
Off-the-shelf commercial UPS equipment fails in railway applications. PARWATT signalling power systems are designed from first principles for the unique demands of the trackside environment:
- Wide-Temperature Operation: Full-rated performance from -25°C to +70°C ambient, with conformally coated PCBs protecting against condensation and humidity ingress. Battery cabinets include active thermal management to maintain optimal cell temperature across all operating conditions.
- Vibration and Shock Hardening: Ruggedised mechanical design with reinforced mounting points, anti-vibration damping on all internal assemblies, and connectors rated for continuous exposure to railway-induced vibration spectra.
- EMC Compliance to EN 50121-4: Full electromagnetic compatibility with traction power systems operating at up to 25kV AC and 3kV DC. Input filtering, shielded enclosures, and galvanic isolation prevent interference from propagating through the power supply chain.
- IP65 Enclosure Options: Outdoor-rated enclosures with sealed cable entries, pressure-equalisation vents, and corrosion-resistant construction for coastal and high-humidity environments.
Reliability Architecture for SIL 4 Signalling
PARWATT signalling power systems are designed to support the highest safety integrity levels. Redundant rectifier modules with automatic failover, dual DC output buses, and battery strings sized for extended autonomy ensure that no single component failure can interrupt power to vital signalling functions. Remote monitoring via relay contacts, serial protocols, and SNMP provides real-time visibility of system health to signalling control centres and maintenance teams.
For electrified lines, PARWATT systems accept traction power supply voltages directly — 650V, 750V, or 1500V DC, and 25kV AC — eliminating the need for separate auxiliary transformers and reducing trackside cabinet footprint. For non-electrified lines, standard AC mains input with backup generator compatibility ensures continuity in remote locations with unreliable grid supply.
Compliance and Certification
PARWATT signalling power products are certified to EN 50121-4 (Railway EMC), EN 50124 (Insulation Coordination), EN 50125 (Environmental Conditions), and EN 50155 (Electronic Equipment on Rolling Stock — applied to trackside equipment by extension). Our quality management system is certified to ISO 9001:2015 and IRIS (ISO/TS 22163) for the railway sector.
Keep your signals live and your trains moving. Contact PARWATT to discuss your signalling power requirements with our railway engineering team.
