ST vital relays, electrical hardware, signal enclosures, accessories


More than

  • ST vital relays in service today governing the safe movement of trains and protecting highway grade crossings.

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ST vital relays

Quality and support you can count on

Siemens has been making vital relays for over 30 years and will continue to manufacture and support them for many years to come. There is no planned end of life.

ST Series vital relays are compact plug-in circuit switching elements housed within a clear polycarbonate case for use in modern railway systems. These relays incorporate the required control characteristics as well as operating security for this application. ST-1 and ST-2 relays fit into size 1 and 2 sockets already in use commonly throughout the industry. Selected models are interchangeable with other manufacturers’ existing types of relays as well.


Each relay carries a relay registration plate unique to that specific type. Sockets have uniform indexing pins to ensure insertion of the proper relay for each circuit function. All contact and coil connections are brought out through the base of the relay as spring prongs. The socket has wedge-shaped plug insulators with flat metal terminals on both the upper and lower surfaces.


Relays are guided into the socket by two rods so that each pair of prongs engage their respective socket terminals, making a firm, low resistance contact. The socket terminals are available in either the solder or crimp types. Terminals are easily removed from the back of the socket for making wiring changes without unplugging the relay.

Features: Vital relays in ST-1 and ST-2 frame sizes

  • Available in both ST-1 and ST-2 frame sizes
  • Mounts easily in existing socket bases
  • All ferrous metal parts are nickel plated
  • Meets or exceeds all applicable AREMA specifications
  • Contact support springs are phosphorous bronze, molded in phenolic blocks. Relays are provided with space for three such blocks.
  • Regular, heavy-duty, extra heavy-duty; tungsten and magnetic arc suppressed contacts are available
  • Heavy armature provides for positive drop-away
  • Highly efficient magnetic structure makes routine calibration quick and easy


Please refer to the individual relay specifications for technical details on contact material and current carrying capacity.

'Relay Products' product brochure


Electrical hardware

Benefit from competitive pricing and short lead times

Resistors/resistance units

Terminal blocks

Signal enclosures/instrument housings

Fulfil all your requirements with customer-specific designs

Instrument houses are available in several sizes and configurations. Available in welded aluminum or steel shell construction with doors that can be completely removed or locked at 90° open position with hooks and locking rods included. Doors can be designed in a variety of arrangements.


  • Meets or exceeds applicable AREMA specifications
  • Available in multiple standard sizes from 4’ (1.22 m) x 4’ (1.22 m) to 8’ (2.44 m) x 8’ (2.44 m) (other sizes may be available upon client request)
  • Adjustable legs for leveling of foundations
  • Interior aerial outlet standard
  • Interior ground terminal plate standard
  • Interior light standard
  • Exterior generator outlet standard
  • Medium-density fiberboard interior finished panels painted with fire retardant paint
  • Ventilation louvers equipped with covers to reduce possible pests
  • Steel shell variants painted with primer and finished with aluminized paint
'Instrument housing products' product brochure



Some of the most widely used tools and accessories in the industry

'Tools & Accessories' product brochure



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