Relay Technology in Railway Signalling

A relay using a heat-activated contact, along with a neutral line relay, to create a time delay to energize an external circuit.

A relay that uses charging/discharging or clock pulses to create a time delay; often fail-safe.

A relay available in mini, minor, and major groups, each with different capacities for neutral control relays and interconnection.

Different time-delay relay technologies, including DC thermal, motorized clockwork, motor-based, and electronic types.

A 10% increase in voltage may reduce time delay to 10%, while a 10% decrease may reduce time delay to 20% in some DC Thermal Type relays.

A relay is an electromagnetic device used to switch electrical circuits on or off.

Relays can be categorized as Shelf type and Plug-In type, with plug-in relays connecting to prewired terminals.

QN1 relay is an internal relay for control/detection circuits (except AC RE area external circuits), immune to 300 VAC 50Hz, but specialized use in emergencies with AC protections.

QS3 Style Relay is a sensitive line relay operating on 12VDC.

QB3 relay is a biased neutral line relay, operating on 12VDC with a 4F/2B contact configuration, suitable for use up to 240V DC biasing.

QNN1 style relay consists of two independent neutral line relays with shared components, having equal front and back contacts.

The relay design should intrinsically prevent contact operation with 1000 V (RMS) 50Hz AC input at coil terminals; also, avoid contact breaking at terminals with 300V (RMS) 50 Hz AC input.

A relay typically includes base electromagnet, armature, contact spring, contacts, transparent cover, and a handle, operating with low current.

Interface relay in Electronic Interlocking systems with a copper slug on the core for immunity.

DC biased AC immune neutral line relay with a copper slug and permanent magnet for biasing.

Similar to QBA1, but with two heavy-duty front contacts capable of handling 30A inductive current.

Repeater for immunized 'Q' series track relays; slow pickup and release.

Magnetically latched DC line relay; remains operated even if power is cut off.

Track relays use a metal to carbon contact type and are usually plug-in for electrified and non-electrified areas.

9 ohm DC non-AC immunized (plug-in) relays are used in non-electrified areas.

9 ohm DC neutral, AC immunized, biased relays are used in electrified areas.

A relay type for AC and DC traction areas, operating at 83.33 Hz and 50 Hz respectively. Vane type relays are acceptable for use until replacement.

Used in signaling circuits to release interlocking after a set time period for safety.

Relays used with coded, pulsed, electronic (audio/high frequency) track circuits; approved type or manufacturer recommendations apply.

Up to 450 meters with choke at both ends, 1000 Amps, and 350 meters without choke (600 Amps).

Up to 750 meters with choke in RE areas.

Relays used in signal control systems for various functions and configurations. Different types offer varying degrees of protection and use in relay interlockings. They have different resistances.

Relays that work in coordination to control signals and points, often in multiple aspects and control groupings.

Relays designed to eliminate interference from AC signals. They are used in specific signal and control circuits.

Relays with two coils, often used in point control circuit of interlocking systems. They are in 5F/3B contact configuration.

A specific relay type used as a lamp proving relay in interlocking systems. It has a particular contact and resistance.

Another relay used for point detection, similar to WKR1 but may have variations.

Relays grouped together to monitor and control signal aspects in interlocking systems.

A relay with a 1 to 5 minute adjustable time range, used for time delay, driven by a synchronous motor that actuates contacts after the preset time.

The current required to activate the ECR relay, which is 108 mA/AC, 50Hz.

The current level below which the ECR relay deactivates, which is 72 mA/AC, 50Hz.

The maximum current that the ECR relay can handle continuously, which is 250 mA/AC, 50Hz.

The ECR relay has 4 sets of contacts (4F-4B) arranged identically in A to D rows.