Chapter III Signals - Vocabulary Flashcards

Glossary of key terms related to Chapter III Signals and their provisions, including fixed, distance, switching, and safety signaling elements.

Signals

Rules for controlling train movement using fixed, hand, detonating, and warning signals.

Colour light signal

Fixed signal using fixed color lights to display aspects; same display by day and night.

Position light signal

Type of colour-light signal where the arrangement of lights indicates the aspect.

Warner signal

Signal to warn the loco pilot of block ahead or approaching a Stop signal; may be a post with a fixed green light.

Distant signal

Semaphore distant signal giving a preliminary indication ahead of the next Stop signal.

Two-Aspect Distant Territory

Distant signal territory with two aspects for signalling.

Multiple-Aspect Distant Territory

Distant signal territory capable of displaying more than two aspects.

Double distant signal

Arrangement of an outer and an inner distant signal, each displaying different aspects.

Stop signal

Signal requiring a train to stop; can be semaphore or colour-light, with various quadrants.

Outer signal

First Stop signal at a station, located outside the obstructing area after Line Clear.

Home signal

First Stop signal of a station when Outer signal is not provided.

Routing signal

Signal indicating which diverging route is set for the loco pilot.

Starter

Last Stop signal of a station guiding departures when only one starter is provided.

Advanced Starter

Outermost Starter when more than one is provided, protecting first facing points.

Intermediate Block Signal (IBS)

Home signal provided at an Intermediate Block Post.

Semi-Automatic Stop signal

Colour-light stop signal that can operate as Automatic or Manual depending on block status.

Automatic Stop signal

Stop signal automatically controlled by train movement in Automatic Block territory.

Calling-on signal

Subsidiary signal below a Stop signal with no independent ON aspect; signals to draw ahead with caution.

Shunt signals

Subsidiary signals for shunting movements; may be disc, miniature semaphore, or other types.

Repeating signal

Signal placed behind a fixed signal to repeat its aspects to the approaching train; marked with R.

Co-acting signals

Duplicate signals fixed below main signals so main arm/light remains visible.

Distinguishing markers

Markers on signals (A, IB, C, R, G, P, etc.) to identify type and purpose.

A marker

'A' on a black on white disc marks an Automatic/Automatic Stop indication.

P marker

'P' on a white disc marks a distant or related signal indication.

IB marker

'IB' on a white disc marks an Intermediate Block Stop signal.

C marker

'C' on a white disc marks a Calling-on signal.

R marker

'R' on a white disc marks a Repeater signal.

G marker

'G' on a yellow disc marks a Gate Stop signal.

AG marker

AG marker is lit when a gate is open or has failed in semi-automatic/automatic territory.

Visibility Test Object (VTO)

Marker or object used to test signal visibility in fog for detonator placement.

Detonators (fog signals)

Explosive devices placed on rails to warn approaching trains in poor visibility; replaced after passage of trains.

Detonator stock and testing

Stock, storage, testing, and destruction rules for detonators; standard life and extension rules.

Fog signalmen

Staff placed to place detonators and manage fog signal duties at stations.

Back-lights

Back-light on signals to indicate whether the signal lamp is burning.

Line Admission Book

Book used to allocate lines for train reception and ensure line clearance before arrival.

Line Clearance

Authority that the line ahead is clear for a train to proceed.

Interlocking

A system that prevents conflicting movements by coordinating signals and points; has failure procedures.

Sighting Committee

Group that inspects fixed signals for visibility before commissioning.

Sighting

Process of verifying signal visibility and effectiveness; part of the commissioning procedure.

Body of rules type

Rules governing the placement and operation of signals, stops, and related devices across stations and lines.