Glossary of Terms


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Danger (aspect)
An indication given by a signal to stop.

Non-preferred
Disciplines: Train Control, Operations
Danger Zone
Everywhere within 3m horizontally from the nearest rail and any distance above or below this 3m, unless a safe place exists or has been created.

Preferred
Disciplines: ALL Disciplines, Operations
Dangerous Goods
Materials defined under the Australian Code for the Transport of Dangerous Goods by Road and Rail ADG code.

Preferred
Disciplines: ALL Disciplines
Dangerous Goods Licence
Required by State or Territory legislation for the storage of dangerous goods above minor thresholds.

Preferred
Disciplines: ALL Disciplines
Dark Territory
Track where the system of Safeworking does not indicate the real-time position of rail traffic.

Regional
Disciplines: Train Control, Operations
Data (signalling)
Site specific geographical and control information in an electronic form, which may be of safety-critical nature or otherwise.

Regional
Disciplines: Train Control
Data Event Logger, Data Logger Or Data Recorder
Train safety recording device.

Alternative
Disciplines: Rolling Stock
Refer to Event Recorder.
Preferred
Disciplines: Rolling Stock
Related Term: Event Recorder
DC Track Circuit
A track circuit with a direct current track feed.

Regional
Disciplines: Train Control, Electrical
DDA
Abbreviated term for the 'Australian Disability Discrimination Act' 1992.

Preferred
Disciplines: ALL Disciplines
De-energised Overhead Wiring
Disconnected from any live electrical equipment, usually by the opening of a circuit breaker.

Preferred
Disciplines: Electrical
De-energised Position
The position assumed by the moving member of an electromagnetic device when the device is deprived of its operating current. Mostly the moving member opens and closes electrical contacts which are used in control and/or indication circuits.

Preferred
Disciplines: Electrical
Dead End Signal
Shunting signals applying to short movements from the running line to a dead end siding or yard.

Regional
Disciplines: Train Control
Dead Locking
Locking which is not conditional on any other control.

Regional
Disciplines: Train Control
Dead Section
A section of track, either within a track circuit or between two track circuits, the rails of which are not part of a track circuit for detecting trains.

Regional
Disciplines: Train Control, Electrical
Deadman System
A vigilance system which reacts by making a penalty brake application, if a continuous control input required of the driver is interrupted or not detected.

Legacy
Disciplines: Rolling Stock
Also known as an 'operator enable system' or 'driver safety control'.
Preferred
Disciplines: Rolling Stock
Defect Card - Green Card
A card placed in the waybill clip of a vehicle to notify all concerned that repairs are required on that vehicle, however the vehicle may remain in traffic until it is operationally practicable to effect those repairs.

Preferred
Disciplines: Rolling Stock
Defect Card - Red Card
A card placed in the waybill clip of a wagon to notify all concerned that that particular vehicle is NOT fit for traffic and must be repaired prior to returning to traffic.

Preferred
Disciplines: Rolling Stock
Degraded Mode Conditions
The state of the part of the railway system when it continues to operate in a restricted manner due to the failure of one or more components.

Preferred
Disciplines: Train Control
Degraded Mode Operations With Train Protection & Control (TPC)
This is operations with Train Protection And Control (TPC) System but when some part of the TPC system has failed.
E.g.: Failure of signal equipment, train-track communication, driver display, services or some operating parameter of the System is not yet validated.

Preferred
Disciplines: Train Control, Operations
Delayed Action Electro-mechanical Treadle
Electro-mechanical treadle the contacts of which being actuated return to the original, position after a certain delay.

Preferred
Disciplines: Electrical
Delayed Yellow (aspect)
A signal to which approach control has been applied where speed must be reduced before the next signal, for example warning (route class).

Regional
Disciplines: Train Control, Operations
Delegate
A Competent Worker authorised and designated to act in place of another.

Preferred
Disciplines: ALL Disciplines
Demarcation Fencing
Easily-seen, continuous worksite safety boundary markers approved by the Rail Infrastructure Manager.

Preferred
Disciplines: Infrastructure
Departure Train Examination (DX)
DX (roll by) examinations are to be conducted where possible on departure from a train's originating location en route. Depending upon the location and the availability of staff, these examinations may be performed by examining staff, train crews, yard or station staff.

Regional
Disciplines: Operations
Dependability
A collective term used to describe the availability performance and its influencing factors: reliability performance, maintainability performance and maintenance support performance. It is non-quantitative.

Preferred
Disciplines: Rolling Stock
Dependent Contact
A changeover contact of a relay where the contact armature connects to either a front contact point or a back contact point, depending on whether the relay is energised or de-energised.

Regional
Disciplines: Electrical, Train Control
Depression Bar
A bar fixed along side the rail at rail level and when depressed by the flanges of a wheel prevents the movement of points.

Regional
Disciplines: Infrastructure, Rolling Stock
Derail Device
A device intended to guide the wheels of rail traffic off rails.

Preferred
Disciplines: Infrastructure, Operations
Derailer
A specially shaped block placed over one rail of a siding to protect main line traffic from any runaway vehicles or unauthorised moves. This protection is achieved by derailing any locomotive or wagon that comes in contact with the derail. In some terminals derails are also used to prevent unauthorised entry into sidings. Alternative device to protect vehicles rolling away onto the main line: catch point.

Preferred
Disciplines: Infrastructure, Operations
Derailment
An incident in which one or more wheelsets run off the track.

Preferred
Disciplines: Rolling Stock, Operations
Design Certification
Certification that the design complies with the defined standards and requirements.

Preferred
Disciplines: ALL Disciplines
Design Details
Any plans, control tables, engineering details and data that are required to sufficiently define the signalling system.

Regional
Disciplines: Train Control
Design Integrity Test
This is a system interlocking and control function test similar to the function test to the control tables, but working from the operational requirements and signalling principles, not directly from Interlocking and control tables or aspect sequence charts.

Regional
Disciplines: Train Control
Design Neutral Temperature
Design temperature at which there are no temperature induced stresses in the rail. Used in relation to continuously welded rail or rail with mechanical joints where a rail joint gap is also specified.

Preferred
Disciplines: Infrastructure
Design Verification
A design check made by an independent competent professional engineer.

Preferred
Disciplines: ALL Disciplines
Destress
The procedure used to ensure that there is no longitudinal stress in a rail when it is at a nominated stress free temperature.

Preferred
Disciplines: Infrastructure
Detectable
Rolling stock able to reliably activate track circuits.

Preferred
Disciplines: Rolling Stock, Train Control
Detection (of Points)
The proof of the position of the points (normal or reverse) to the interlocking equipment.

Preferred
Disciplines: Train Control
Detonating Signals
Impact explosive devices secured on top of the rail of the track to be protected, to attract the attention of train crews.

Obsolete
Disciplines: ALL Disciplines
Detonator
Refer to Railway Track Signal

Obsolete
Disciplines: ALL Disciplines
Related Term: Railway Track Signal
Detonator Placer
An appliance for placing one or more detonators on the running line.

Obsolete
Disciplines: ALL Disciplines
Diamond Crossing
An arrangement of 2 'V' and 2 'K' crossings together with two pairs of guard rails whereby one track crosses another.

Preferred
Disciplines: Infrastructure
Diesel Locomotive
A locomotive in which electric current from a diesel motor driving generators or alternators is delivered to traction motors on the axles for propulsion.

Preferred
Disciplines: Rolling Stock
Differential (speed Restriction)
A speed restriction having up to three values, each of which is applicable to different types of train.

Regional
Disciplines: Train Control, Operations
Dimming Switch
A switch, located in a signal box, used to decrease the brightness of colour light signals at night and increase it during daylight.

Regional
Disciplines: Train Control
Dip
A downward variation in the running surface of a rail as may occur at welds or rail ends.

Legacy
Disciplines:
Direct Fixation
The system of fixation of track directly to a structure or continuous concrete base.

Preferred
Disciplines: Infrastructure
Direct Interlocking
Interlocking produced by direct action of the interlocking apparatus (or groups of apparatus) on the fittings interlocked and which is independent of all other apparatus.

Preferred
Disciplines: Train Control
Direct Opposing Locking
Interlocking between two routes in opposite directions for which the lie of all points is the same.

Regional
Disciplines: Train Control
Direct Track Locking
Locking of movable components, for example, points when a train is present. This is not conditional on the points being set or locked.

Regional
Disciplines: Train Control
Refer to Dead Locking.
Alternative
Disciplines: Train Control
Related Term: Dead Locking
Direct Traffic Control (DTC) Territory
The portions of line where the Direct Traffic Control system of Safeworking is used.

Regional
Disciplines: Train Control, Operations
Direction Lever
A non-token system of single line working usually requiring continuous train detection through the section. A form of track circuit block.

Regional
Disciplines: Train Control
Directional Travel Station
A station at which the points are normally set to allow simultaneous entry and exit of trains through the up and down lines.

Preferred
Disciplines: Train Control, Operations
DIRN
Defined Interstate Rail Network


Disciplines:
Abbreviation for 'Defined Interstate Rail Network'.
Preferred
Disciplines: ALL Disciplines, Rolling Stock
Disabled
In realtion to rail traffic, Unable to travel without assistance due to a defect.

Preferred
Disciplines: ALL Disciplines, Operations
Disc Signal
Display a red signal during daylight or coloured lights at night or where visibility is reduced.
Or
A shunting signal or subsidiary signal consisting of a small disc which rotates to indicate a change of aspect.

Regional
Disciplines: Operations, Train Control
Disconnected Signal
A signal that has been adjusted to ensure that it shows only the most restrictive aspect for one or more of its routes.

Regional
Disciplines: Train Control
Disconnection Box
The disconnection or restriction of use of signalling equipment agreed between maintenance and operations staff to enable work to be carried out on the equipment.
Also see 'possession'.

Overseas
Disciplines: Train Control, Operations
A small housing containing cable terminations to enable cable size changes or disconnections to be made.
Regional
Disciplines: Electrical
Discreet Channel
A system in which only the intended participants in a radio or telephone conversation can take part in the conversation.

Preferred
Disciplines: ALL Disciplines
Distant Board
A reflectorised sign that is equivalent to a fixed distant signal.

Regional
Disciplines: Train Control
Refer to Landmark.
Regional
Disciplines: Train Control
Related Term: Landmark
Distant Lookout
A qualified and competent worker who provides advance warning to the site lookout.

Preferred
Disciplines: ALL Disciplines
Distant Signal
A signal (not itself a stop signal) capable of displaying a cautionary aspect that informs the driver of the state of the signals or level crossing ahead.

Regional
Disciplines: Train Control
Disturbed Or Abnormal Operations With TPC
This is when all TPC systems are operating but an external operational constraint is imposed to mitigate risk to operations.
(E.g.: Application of a temporary speed restriction or re-routing of normal services.)

Preferred
Disciplines: ALL Disciplines, Operations
Diverging Line
Dividing into two lines.

Preferred
Disciplines: ALL Disciplines
Diverging Route
In the signalling of junctions, any route that diverges from the fastest/equal or straight route.

Regional
Disciplines: Train Control
DLB
Double line Block


Disciplines:
DMU
Diesel Multiple Unit


Disciplines:
Abbreviated term for 'diesel multiple unit', a multiple-unit passenger train in which the propulsion power is supplied by a diesel engine.
Alternative
Disciplines: Rolling Stock
Dog Chart
A pictorial representation of the interlocking elements required to make-up mechanical locking.
An alternative term for locking chart.

Regional
Disciplines: Train Control
Dogspike
A steel fastener used on timber sleepers for holding down rail at the foot and to maintain gauge.

Preferred
Disciplines: Infrastructure
DOI
Department of Infrastructure (Vic)


Disciplines:
Abbreviated term for 'Department of Infrastructure' (Victoria).
Alternative
Disciplines: ALL Disciplines
Doll
A short post on a cantilever or gantry, on which is mounted one or more semaphore signals.

Regional
Disciplines: Train Control
DOO
Driver Only Operation


Disciplines:
DOTARS
Department of Transport and Regional Services


Disciplines:
Abbreviated term for 'Department of Transport and Regional Services'.
Alternative
Disciplines: ALL Disciplines
Double Check Gauge
The distance between the guard edges of double check rails.

Preferred
Disciplines: Infrastructure
Double Junction
The point of junction of two double track routes. It comprises two turn outs and a diamond crossing.

Regional
Disciplines: Infrastructure
Double Light Signalling
A system of colour light signalling where a running signal indication is given by two colour lights.

Regional
Disciplines: Train Control
Double Line
Two adjacent, parallel, running lines. In double line areas, trains are generally permitted to travel in one direction only on each line (except during bi-directional or single line working).

Preferred
Disciplines: ALL Disciplines
Double Line Block (DLB) Territory
The portions of line where the Double Line Block system of Safeworking is used.

Preferred
Disciplines: Train Control, Operations
Double Line Working
The operation of two parallel main lines carrying traffic in each direction on a separate track.

Preferred
Disciplines: ALL Disciplines
Double Or Delta Crossover
Crossingwork assembly comprising two crossovers intersecting in the form of a diamond between the centrelines of the outside tracks.

Preferred
Disciplines: Infrastructure
Double Rail Track Circuit
A track circuit which uses both rails for signalling purposes. In electrified areas both rails are also used as traction return rails.

Preferred
Disciplines: Electrical, Train Control
Double Shoulder Plate
A rail support plate designed with a shoulder on each side of the rail foot which is normally used with dogspikes.

Preferred
Disciplines: Infrastructure
Double Slip
A combination of a diamond crossing with four point ends without the need of separate crossings (points).

Regional
Disciplines: Infrastructure
Double Stack
This refers to the practice of stacking one container on top of another on a wagon. This allows more containers to be carried for the given train length, making the trains more efficient. It is currently only possible to double stack within the area bounded by Adelaide, Parkes in western NSW, Perth and Alice Springs primarily due to tunnels and lower bridges in the eastern states.

Regional
Disciplines: Rolling Stock, Operations
Double Switched Circuits
Circuits which are switched on both the active and common (or positive and negative) sides of the controlled function by each of the controlling functions.

Regional
Disciplines: Train Control, Electrical
Double Track
Consists of two parallel tracks, typically for trains travelling in opposite directions at the one time without the need for passing loops.

Preferred
Disciplines: ALL Disciplines
Double Yellow (aspect)
A preliminary caution displayed by a colour light signal in four aspect signalling informing the driver to expect the next main signal to be at single yellow.

Regional
Disciplines: Train Control
Down Line
In a double line area, the lines are generally referred to as the Down Line and Up Line. Usually, the down line is used by trains travelling away from the State Capital. However, local notices should be referenced to check this at any location.

Regional
Disciplines: Train Control, Operations
DPI
Department of Primary Industries (WA)


Disciplines:
Department of Planning and Infrastructure (NT)

Disciplines:
Abbreviation for 'Department of Primary Industries'
(WA)
Alternative
Disciplines: ALL Disciplines
DPI (NT)
Abbreviation for 'Department of Planning and Infrastructure' (NT).

Alternative
Disciplines: ALL Disciplines
DPTI
Department of Planning Transport and Infrastructure (SA)


Disciplines:
DPTI (SA)
Abbreviated term for 'Department of Planning, Transport and Infrastructure' (SA).

Preferred
Disciplines: ALL Disciplines
DRA
Drivers Reminder Appliance


Disciplines:
Draftgear
Components which provide resilience in the connection of the coupling system to the structure of the rolling stock.

Preferred
Disciplines: Rolling Stock
Draftgear Yoke
The component of the drawgear connected to the coupler within which the draftgear resides.

Preferred
Disciplines: Rolling Stock
Draw Ahead (aspect)
A position light subsidiary signal that instructs the driver to 'draw ahead', for example, sufficiently to enable a set back move over a trailing connection to take place.
An alternative term for 'calling-on' or 'shunt-ahead signal'.

Regional
Disciplines: Train Control
Draw Hook And Screw Coupling
A coupling system between rolling stock which can only accept draft loads and relies on headstock buffers to accept buffing loads.

Legacy
Disciplines: Rolling Stock
Drawbar
A rigid connection between two items of rolling stock which is only intended to be separated in a shop, rather than in normal operation.

Preferred
Disciplines: Rolling Stock
Drawgear
A set of fittings used to connect railway vehicles for the purpose of transmitting longitudinal forces between adjacent vehicles; connection can be made manually or automatically.

Preferred
Disciplines: Rolling Stock
Drive Rod
The rod between the drive mechanism and the front rod.

Regional
Disciplines: Train Control
Driver
A Competent Worker controlling the movement of rail traffic.

Non-preferred
Disciplines: ALL Disciplines
Refer Rail Traffic Crew
Alternative
Disciplines: ALL Disciplines
Driver Only Operation (DOO)
A method of working which permits trains to operate without the need of a guard.

Preferred
Disciplines: ALL Disciplines, Operations
Driver Supervisory System
A system fitted to a vehicle that can monitor the driver (or train) condition or performance and apply the train brakes when a measured condition or performance parameter violates a required state or limit.

Preferred
Disciplines: Rolling Stock, Operations
Driver-alone Operation
Operations in which one sole rail safety worker has the responsibility for the control, operations and procedures of a train.

Regional
Disciplines: Operations
Drivers Reminder Appliance (DRA)
A device in a driving cab to enable the driver to set a reminder. Whilst set it prevents the driver from taking power.

Regional
Disciplines: Operations, Train Control
DSFAPT
Abbreviation for the 'Disability Standards for Accessible Public Transport' 2002 and Amendments which states requirements for transport providers and operators to meet the Disability Discrimination Act.

Alternative
Disciplines: ALL Disciplines, Rolling Stock
DSFAT
Disability Standards for Accessible Public Transport 2002


Disciplines:
DTC
Direct Traffic Control


Disciplines:
DTEI
Department of Transport, Environment and Infrastructure (SA)


Disciplines:
Abbreviated term for 'Department of Transport, Environment and Infrastructure' (SA).
Obsolete
Disciplines: ALL Disciplines
DTMR
Department of Transport and Main Roads (QLD)


Disciplines:
Department of Transport and Main Roads. (QLD)
Preferred
Disciplines: ALL Disciplines
Dual Control Points
A power operated point machine also equipped for hand operation.

Regional
Disciplines: Train Control, Infrastructure
Dual Gauge Crossingwork Assembly
An assembly of crossingwork arranged to permit both broad gauge and standard gauge traffic on the through and turnout moves.

Preferred
Disciplines: Infrastructure
Dual Gauge Track
Track that is constructed with a mixture of both standard gauge (1435 mm) and broad gauge (1600 mm) widths, or standard and narrow gauge (1067 mm) widths utilising a common rail.

Preferred
Disciplines: Infrastructure, Operations
Dual Gauge Turnout
A turnout incorporating dual gauge crossingwork units.

Preferred
Disciplines: Infrastructure
Dummy Hose Coupling
A casting, the same shape as a hose coupling, into which the coupling may be hooked. It is used to prevent dirt from getting into the brake pipe as well as preventing the hose coupling from being damaged when not in use.

Preferred
Disciplines: Rolling Stock, Operations
Dummy Point Slide Chair
The short point slide chair ahead of the toe of the switch.

Preferred
Disciplines: Infrastructure
Dunnage
Loose material such as timber, steel or synthetic beams or wedges laid beneath or wedged between loads carried by rail to support, separate or restrain loads and prevent damage.

Legacy
Disciplines: ALL Disciplines
Duplex
A communication system that can transmit and receive at the same time, similar to a telephone system.

Preferred
Disciplines: Train Control, Operations
Duplex Lock
A lock operated by an annett key to release another annett key which is then used to unlock signalling equipment. One key is always held captive in the duplex lock when the other is out.

Regional
Disciplines: Train Control
Dwarf Signal
Small size semaphore or colour light signals which can be either mechanically or power worked. These signals are usually used where they can be easily seen from short distance and the speed of approaching trains is low, such as in a shunting yard.

Regional
Disciplines: Train Control, Operations
DX
Departure Train Examination


Disciplines:
Dynamic Behaviour
The performance of the vehicle when moving along the track.

Preferred
Disciplines: Rolling Stock
Dynamic Braking
Braking that uses the momentum of the locomotive and train to cause a braking effect. The traction motors are in effect turned into generators and the power is dissipated as heat through fan blown grids on the locomotive.

Preferred
Disciplines: Rolling Stock, Operations