Track Relay Solution
The rail transit industry imposes stringent requirements on equipment reliability, vibration resistance, and wide-temperature adaptability. Relays are widely used in core areas such as signal interlocking, traction control, auxiliary system driving, and safety protection.
Signal Interlocking System
System Role: The “brain” of rail transit.
Core Component: Dedicated signal relays.
Key Requirement: Must comply with rail-specific standards such as EN 50155, ensuring stable operation in high-vibration and wide-temperature environments.
Main Types and Applications:
Neutral Relays: Primarily used for signal detection in track circuits.
Polarized / Biased Relays: Primarily used for indication and control of switch (point) positions.
Train Traction System
Core Requirement: High-power, highly reliable switching control.
Main Types and Applications:
High-Voltage DC Relays: Used for main circuit switching control between converters and traction motors.
Solid-State Relays (SSR): Used to drive auxiliary equipment in the traction system, such as compressors and heaters, enhancing system reliability and lifespan through contactless switching
Vehicle Auxiliary System
Core Requirement: Stable driving of various on-board equipment, compatible with the train’s power supply system.
Main Types and Applications:
Electromagnetic Intermediate Relays: Coil voltage is typically compatible with the train’s DC power supply system, used for controlling equipment like air conditioning, lighting, and doors.
Time-Delay Relays: Used in scenarios requiring precise timing control, such as delayed door opening/closing and delayed air conditioning startup.
Safety Protection System
Core Requirement: Highest level of reliability and fail-safe design.
Design Principle: Employs de-energized-to-trip (safety) design, ensuring the hazardous circuit is actively cut off upon failure.
Main Types and Applications:
Safety Relays / Forced-Guided Contact Relays: Used in critical safety circuits such as emergency braking circuits and ATP (Automatic Train Protection) system interfaces.
Monitoring and Protection Relays:
Voltage/Current Relays: Used for monitoring grid voltage and traction motor current.
Differential Relays: Used for differential protection of traction transformers.