Fail-safe Relays

For over 20 years, Intertech Rail has specialized in the design and manufacturing of Fail-Safe Rail Relays, essential components widely applied in railway signaling and control systems.


With more than 300 variations available, all relays are engineered under the fail-safe principle: in the event of any malfunction or breakdown, the relay automatically returns to its safest position through gravity and mechanical design. This guarantees maximum reliability and compliance with the highest railway safety standards.


Fail-Safe Relays remain the preferred solution in the railway industry due to their proven durability, operational stability, and ability to secure safe performance in critical applications.


Intertech Rail manufactures the full spectrum of relay types on demand, with the B1 and B2 models being the most commonly used and detailed in our catalogs. We also supply legacy and discontinued relay models. Simply provide the required Relay Part Number to receive a tailored quotation.

ON-TRACK INSTALLATIONS | FAIL-SAFE RELAYS

  • Fail-safe relays for on-track installations with railway signal and relay cabinet collage

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  • Fail-safe relay for railway signaling by Intertech Rail

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  • Fail-safe relay for railway signaling by Intertech Rail

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  • Fail-safe relay for railway signaling by Intertech Rail

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Frequently Asked Questions

  • What is an Overload relay?

    The overload relay is designed to protect motors from excessive current. In rail applications, overload relays are commonly used in the power supply systems of trains. If the motor draws too much current, the overload relay will trip, preventing damage to the motor and ensuring the safety of the system.

  • That is a Fail-safe Thermal relay


    Thermal relays are used to protect motors from overheating. They work by measuring the temperature of the motor and tripping if it exceeds a preset value. In rail applications, thermal relays are commonly used in the traction systems of trains. If the motor overheats, the thermal relay will trip, preventing damage to the motor and ensuring the safety of the system.

  • What is a fail-safe Earth fault relay?

    Earth fault relays are used to detect faults in the insulation of the system. In rail applications, earth fault relays are commonly used in the track circuits. If a fault occurs in the insulation of the track circuit, the earth fault relay will trip, isolating the section of track and preventing damage to the system.

  • What is a fail-safe Short circuit relay?

    Short circuit relays are used to protect the system from short circuits. In rail applications, short circuit relays are commonly used in the traction systems of trains. If a short circuit occurs, the short circuit relay will trip, isolating the faulty section of the system and preventing damage to the system.

  • What is a Time delay relay?

    Time delay relays are used to provide a time delay before tripping. In rail applications, time delay relays are commonly used in the power supply systems of trains. If a fault occurs in the system, the time delay relay will provide a delay before tripping, allowing the system to recover from a momentary fault and preventing unnecessary trips.

Intertech Rail Relay Cross-Reference Table

  • Neutral Relays

    • Intertech PN 2-04-3-1-951-01 | Siemens 400000 | GRS A62-262 | Contacts: 6FB | Coil resistance: 500
    • Intertech PN 2-04-3-1-783-01 | Siemens 400003 | GRS A62-308 | Contacts: 4FB-2F-1B | Coil resistance: 900
    • Intertech PN 2-04-3-1-783-02 | Siemens 400004 | GRS A62-277 | Contacts: 4FB-2F-1B | Coil resistance: 500
    • Intertech PN 2-04-3-1-787-01 | Siemens 400011 | GRS A62-276 | Contacts: 4FB-2F-1B | Coil resistance: 4
    • Intertech PN 2-04-3-1-714-03 | Siemens 400013 | GRS A62-260 | Contacts: 6FB | Coil resistance: 1.8
    • Intertech PN 2-04-3-1-762-01 | Siemens 400017 | GRS A62-296 | Contacts: 6FB | Coil resistance: 900
    • Intertech PN 2-04-3-1-822-02 | Siemens 400020 | GRS A62-310 | Contacts: 4FB-2F-1B (HD) | Coil resistance: 500
    • Intertech PN 2-04-3-1-822-01 | Siemens 400022 | GRS A62-311 | Contacts: 4FB-2F-1B (HD) | Coil resistance: 900
    • Intertech PN 2-04-3-1-978-01 | Siemens 400023 | GRS A62-580 | Contacts: 6FB (HD) | Coil resistance: 500
    • Intertech PN 2-04-3-1-822-06 | Siemens 400027 | GRS A62-309 | Contacts: 4FB-2F-1B (HD) | Coil resistance: 350

  • Neutral - Switch Control Relay

    • Intertech PN 2-04-3-1-917-01 | Siemens 400025 | GRS A62-427 | Contacts: 4FB (HD) | Coil resistance: 500

  • Slow Pickup Relays

    • Intertech PN 2-04-3-1-736-01 | Siemens 400100 | GRS A62-345 | Contacts: 6FB | Coil resistance: 220
    • Intertech PN 2-04-3-1-790-01 | Siemens 400101 | GRS A62-341 | Contacts: 4FB-2F-1B | Coil resistance: 300

  • Slow Release Relays

    • Intertech PN 2-04-3-1-774-01 | Siemens 400200 | GRS A62-360 | Contacts: 4FB | Coil resistance: 194
    • Intertech PN 2-04-3-1-780-01 | Siemens 400210 | GRS A62-359 | Contacts: 6FB | Coil resistance: 194
    • Intertech PN 2-04-3-1-851-01 | Siemens 400211 | GRS A62-357 | Contacts: 4FB-2F-1B | Coil resistance: 194
    • Intertech PN 2-04-3-1-792-02 | Siemens 400212 | GRS A62-358 | Contacts: 4FB-2F-1B | Coil resistance: 194

  • Light Out Relay (Relay Only)

    • Intertech PN 2-04-3-1-785-61 | Siemens 400302 | GRS A62-217 | Contacts: 4FB | Coil resistance: 450/.069

  • Biased Neutral Relays

    • Intertech PN 2-04-3-1-922-07 | Siemens 400500 | GRS A62-125 | Contacts: 6FB | Coil resistance: 500
    • Intertech PN 2-04-3-1-922-05 | Siemens 400501 | GRS A62-140 | Contacts: 6FB | Coil resistance: 63
    • Intertech PN 2-04-3-1-921-07 | Siemens 400502 | GRS A62-122 | Contacts: 4FB-2F-1B | Coil resistance: 500
    • Intertech PN 2-04-3-1-927-01 | Siemens 400503 | GRS A62-552 | Contacts: 2FB-4F-2B | Coil resistance: 1000
    • Intertech PN 2-04-3-1-963-01 | Siemens 400507 | GRS A62-637 | Contacts: 5F-4B | Coil resistance: 4
    • Intertech PN 2-04-3-1-961-01 | Siemens 400508 | GRS A62-639 | Contacts: 5F-4B | Coil resistance: 0.5
    • Intertech PN 2-04-3-1-933-01 | Siemens 400509K | GRS A62-555 | Contacts: 2FB-4F-2B | Coil resistance: 2100
    • Intertech PN 2-04-3-1-965-01 | Siemens 400515 | GRS A62-633 | Contacts: 5F-4B | Coil resistance: 0.5

  • Biased Switch Control Relay

    • Intertech PN 2-04-3-1-926-01 | Siemens 400520 | GRS A62-429 | Contacts: 2F-2B (EHD) | Coil resistance: 500

  • Switch Overload Relay

    • Intertech PN 2-04-3-1-785-01 | Siemens 400600 | GRS A62-432 | Contacts: 2B (EHD) | Coil resistance: .068/1225

  • Flasher Relay

    • Intertech PN 2-04-3-1-985-01 | Siemens 400700 | GRS A62-577 | Contacts: 4FB | Coil resistance: 60