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Questions and Answers
What is the primary function of a Calling-on signal?
What is the primary function of a Calling-on signal?
Under what conditions can a colour light Distant signal be combined with a Stop signal?
Under what conditions can a colour light Distant signal be combined with a Stop signal?
What type of Route Indicator is required for speeds in excess of 15 kmph?
What type of Route Indicator is required for speeds in excess of 15 kmph?
When two or more lines converge, where should the signals be fixed?
When two or more lines converge, where should the signals be fixed?
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What type of signals are recommended for shunt signals according to signalling principles?
What type of signals are recommended for shunt signals according to signalling principles?
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What is the primary consideration for determining the number and height of signals?
What is the primary consideration for determining the number and height of signals?
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What is the purpose of a Route Indicator?
What is the purpose of a Route Indicator?
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What is the significance of a Stop signal being 'ON'?
What is the significance of a Stop signal being 'ON'?
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What is the purpose of the arrow on a signal erected on the right-hand side?
What is the purpose of the arrow on a signal erected on the right-hand side?
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Under what conditions can two or more signals be combined?
Under what conditions can two or more signals be combined?
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Why should signals be located and aligned in a specific way?
Why should signals be located and aligned in a specific way?
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What is the primary purpose of a Stop signal?
What is the primary purpose of a Stop signal?
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What is the primary consideration for the uniformity of signalling at a station?
What is the primary consideration for the uniformity of signalling at a station?
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What is the purpose of limiting the size of lamps/LEDs of Subsidiary Signals?
What is the purpose of limiting the size of lamps/LEDs of Subsidiary Signals?
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What is the reason for avoiding the possibility of the aspect of one signal being mistaken for the aspect of another?
What is the reason for avoiding the possibility of the aspect of one signal being mistaken for the aspect of another?
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Why should Main signals be of the colour light multi-unit type?
Why should Main signals be of the colour light multi-unit type?
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Where should the Home Signal be placed in relation to the points?
Where should the Home Signal be placed in relation to the points?
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What is the purpose of a Routing Signal?
What is the purpose of a Routing Signal?
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When is a Starter Indicator provided?
When is a Starter Indicator provided?
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What is the minimum distance the Home Signal should be placed from the points in certain cases?
What is the minimum distance the Home Signal should be placed from the points in certain cases?
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What is the purpose of an Intermediate Starter Signal?
What is the purpose of an Intermediate Starter Signal?
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In what type of territory is the Home Signal placed at a distance of 180 meters from the points?
In what type of territory is the Home Signal placed at a distance of 180 meters from the points?
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What is the condition for placing the Home Signal at a distance of 300 meters from the points?
What is the condition for placing the Home Signal at a distance of 300 meters from the points?
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What is the aspect of the Starter Indicator when the concerned Starter is 'ON'?
What is the aspect of the Starter Indicator when the concerned Starter is 'ON'?
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What is the minimum distance required for the placement of an Advanced Starter Signal from the outermost points in a Single Line section?
What is the minimum distance required for the placement of an Advanced Starter Signal from the outermost points in a Single Line section?
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What is the primary purpose of an Intermediate Block Stop (IBS) signal?
What is the primary purpose of an Intermediate Block Stop (IBS) signal?
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At what distance from the gate should a Gate Stop Signal be located in a MACLS territory?
At what distance from the gate should a Gate Stop Signal be located in a MACLS territory?
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What is the recommended spacing between Automatic Block Signals?
What is the recommended spacing between Automatic Block Signals?
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When a Signal is displaying the 'Stop' aspect, what is the minimum aspect that the signal next in rear should display?
When a Signal is displaying the 'Stop' aspect, what is the minimum aspect that the signal next in rear should display?
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What is the purpose of a marker consisting of a yellow coloured disc with letter 'G' in black on a Gate Stop Signal?
What is the purpose of a marker consisting of a yellow coloured disc with letter 'G' in black on a Gate Stop Signal?
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What is the minimum distance required for placing a Multiple Aspect Signal that is required to display a 'Caution' aspect to a train?
What is the minimum distance required for placing a Multiple Aspect Signal that is required to display a 'Caution' aspect to a train?
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What is the colour of the disc used as a marker on an Intermediate Block Stop (IBS) signal?
What is the colour of the disc used as a marker on an Intermediate Block Stop (IBS) signal?
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What is the primary design consideration for signal and interlocking circuits in terms of failure?
What is the primary design consideration for signal and interlocking circuits in terms of failure?
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What type of interlocking installation is based on the Entry/Exit principle?
What type of interlocking installation is based on the Entry/Exit principle?
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What is the purpose of providing different colours for each track circuit on the Control Panel?
What is the purpose of providing different colours for each track circuit on the Control Panel?
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What is the primary consideration for providing multiple Control Panels/Control Terminals?
What is the primary consideration for providing multiple Control Panels/Control Terminals?
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What is the purpose of providing inter-slotting controls in installations with multiple Control Panels/Control Terminals?
What is the purpose of providing inter-slotting controls in installations with multiple Control Panels/Control Terminals?
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What type of installation is required to have a Dual VDU in lieu of a Control Panel and VDU?
What type of installation is required to have a Dual VDU in lieu of a Control Panel and VDU?
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What is the primary consideration for the design of the Control Cum Indication Panel (CCIP)?
What is the primary consideration for the design of the Control Cum Indication Panel (CCIP)?
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What is the primary purpose of providing a Control Cum Indication Panel (CCIP)?
What is the primary purpose of providing a Control Cum Indication Panel (CCIP)?
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Where should the Home Signal be placed in relation to the points in a single distant territory?
Where should the Home Signal be placed in relation to the points in a single distant territory?
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Under what condition can the Home signal be placed at a distance of 300 meters from the points?
Under what condition can the Home signal be placed at a distance of 300 meters from the points?
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What is the purpose of a Routing Signal?
What is the purpose of a Routing Signal?
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When is a Starter Indicator provided?
When is a Starter Indicator provided?
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Where should an Intermediate Starter Signal be placed?
Where should an Intermediate Starter Signal be placed?
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What is the aspect of the Starter Indicator when the concerned Starter is 'ON'?
What is the aspect of the Starter Indicator when the concerned Starter is 'ON'?
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What is the purpose of a Starter Signal?
What is the purpose of a Starter Signal?
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What is the minimum distance the Home Signal should be placed from the points in certain cases?
What is the minimum distance the Home Signal should be placed from the points in certain cases?
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What is the primary consideration for the uniformity of signalling at a station?
What is the primary consideration for the uniformity of signalling at a station?
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Why should signals be free from the possibility of phantom indication?
Why should signals be free from the possibility of phantom indication?
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What is the purpose of providing an arrow on a signal erected on the right-hand side?
What is the purpose of providing an arrow on a signal erected on the right-hand side?
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What is the primary consideration for determining the location and alignment of signals?
What is the primary consideration for determining the location and alignment of signals?
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Why should the size of lamps/LEDs of Subsidiary Signals be smaller than that of Main signals?
Why should the size of lamps/LEDs of Subsidiary Signals be smaller than that of Main signals?
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What is the primary consideration for the type of signals used at a station?
What is the primary consideration for the type of signals used at a station?
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Why should signals be electrically lit?
Why should signals be electrically lit?
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What is the primary consideration for the number of signals and their height?
What is the primary consideration for the number of signals and their height?
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What is the primary purpose of slot controls on signals?
What is the primary purpose of slot controls on signals?
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What is the condition under which the Station Master's control over Home Signals can be dispensed with?
What is the condition under which the Station Master's control over Home Signals can be dispensed with?
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What is the primary purpose of providing slot control to the Station Master?
What is the primary purpose of providing slot control to the Station Master?
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What happens when a controlling agency withdraws its control from a slot?
What happens when a controlling agency withdraws its control from a slot?
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What is the purpose of designing slot circuits to be effective for only one train?
What is the purpose of designing slot circuits to be effective for only one train?
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What is the significance of a slot once given?
What is the significance of a slot once given?
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Under what condition is the Station Master provided slot control over the Home and Last Stop Signals?
Under what condition is the Station Master provided slot control over the Home and Last Stop Signals?
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What is the primary purpose of slot controls in the signaling system?
What is the primary purpose of slot controls in the signaling system?
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What is the prerequisite for commissioning of Electronic Interlocking?
What is the prerequisite for commissioning of Electronic Interlocking?
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What is the purpose of Annexure 7-A1 in IRSEM?
What is the purpose of Annexure 7-A1 in IRSEM?
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What is the minimum permissible speed for STD IV interlocking?
What is the minimum permissible speed for STD IV interlocking?
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What type of point operation is required for STD III interlocking?
What type of point operation is required for STD III interlocking?
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What is the requirement for train detection in STD I interlocking?
What is the requirement for train detection in STD I interlocking?
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What is the requirement for block working in STD IV interlocking?
What is the requirement for block working in STD IV interlocking?
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What is the requirement for double distant/automatic signalling in STD II interlocking?
What is the requirement for double distant/automatic signalling in STD II interlocking?
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What is the requirement for mobile train radio communication in STD IV interlocking?
What is the requirement for mobile train radio communication in STD IV interlocking?
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When is a short dead end siding not long enough to permit of vehicles being stabled thereon?
When is a short dead end siding not long enough to permit of vehicles being stabled thereon?
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What is the minimum distance required for a trap to be placed on a dead end siding from the starter signal?
What is the minimum distance required for a trap to be placed on a dead end siding from the starter signal?
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When can a train be admitted on to the running line?
When can a train be admitted on to the running line?
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What is the purpose of a sand hump of approved design?
What is the purpose of a sand hump of approved design?
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What is the minimum length of a siding required when a sand hump is used?
What is the minimum length of a siding required when a sand hump is used?
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When is Method C used?
When is Method C used?
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What is the condition for setting the points of the dead end siding for the across over and against the siding?
What is the condition for setting the points of the dead end siding for the across over and against the siding?
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What is the primary consideration when using Method B or Method C?
What is the primary consideration when using Method B or Method C?
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Study Notes
Signals in General
- Multiple Aspect Colour Light Signalling (MACLS) is covered in this chapter.
- All signals shall be electrically lit and free from the possibility of phantom indication.
Types of Signals
- Main signals: colour light multi-unit type
- Shunt signals: Position Light type
- Calling on signals: may be provided as per operational needs
Uniformity of Signalling
- It is desirable that signalling at all stations and interlocked level crossing gates in a section conforms to the same type and standard as per maximum permissible speed of the section.
- Signalling at a station at either end shall also be uniform as far as possible.
Signals Location
- Signals shall normally be on the left of, or above the line to which they apply, unless authorized by special instructions to the contrary.
- Where signals are erected on the right-hand side, they shall be provided with an arrow, pointing towards the applicable line.
- Signals shall be located and aligned to display the best possible view of their aspects to the Loco Pilot of approaching trains.
- Signals shall avoid confusion between the lights of Main signals and the lights of Subsidiary signals or any other lights.
Combined Signals
- When owing to their location, it is necessary to combine any two signals, one Stop Signal only may be provided under approved special instructions, capable of displaying any or all the following aspects:
- Stop
- Caution
- Attention
- Proceed
Distinction between Signals
- Diverging lines: a route indicator of approved design shall be provided, unless otherwise permitted by approved special instructions.
- Converging lines: unless otherwise permitted by approved special instructions, the signals shall be fixed on separate posts.
Subsidiary Signals
- Calling-on signal: when taken 'OFF' calls on the Loco Pilot of a train to draw ahead with caution, after the train has been brought to a stop even though the Stop Signal above it is at 'ON'.
- Advanced Starter Signal: shall be placed outside all connections on the line to which it applies, at a distance of not less than 120 meters from the outermost points in the case of Single Line section.
- Gate Stop Signal: shall be located at not less than 180 meters in rear of the gate, which it is protecting.
- Intermediate Block Stop (IBS) signal: is the Home signal provided at an Intermediate Block post on a Double Line or Single Line.
- Automatic Block Signals: shall be normally located with a spacing of one km from each other, subject to other criteria and headway required.
Aspects-Sequence
- When a Signal is displaying the 'Stop' aspect, the signal next in rear shall not display a less restrictive aspect than 'Caution'.
- Every Multiple Aspect Signal, which is required to display 'caution' aspect to a train, shall normally be placed at an adequate distance from the next signal in advance.
Operation of Signals & Points - Control Panel
- The Interlocking installations are of two types: Route Setting Type i.e.on the basis of Entry/Exit principle, Non-route Setting Type i.e.Route is set with individual operation of points.
- The points and Signals shall be operated from a Control panel for Relay Interlocking or Control panel and/or Control Terminal (Video Display Unit (VDU)) for Electronic Interlocking.
Essentials of Signalling
Signals in General
- Multiple Aspect Colour Light Signalling (MACLS) is covered in this chapter.
- All signals must be electrically lit and free from phantom indications.
- Main signals shall be colour light multi-unit type, and shunt signals shall be of the Position Light type.
- Calling on signals may be provided as per operational needs.
- It is desirable to have uniformity of signalling at all stations and interlocked level crossing gates in a section.
Signals - Location
- The number of signals and their height shall be limited to what is necessary for safety and operational requirements.
- Signals shall normally be on the left of, or above the line to which they apply, unless authorized by special instructions to the contrary.
- Where signals are erected on the right-hand side, they shall be provided with an arrow pointing towards the applicable line.
- Signals shall be located and aligned to:
- Display the best possible view of their aspects to the loco pilot of approaching trains.
- Avoid the possibility of the aspect of one signal being mistaken for the aspect of another.
- Avoid confusion between the lights of Main signals and the lights of Subsidiary signals or any other lights.
- The size of lamps/LEDs of Subsidiary Signals shall be smaller than that of Main signals.
Home Signal
- The Home Signal shall be placed at not less than 180 meters in rear of the points up to which the line may be obstructed, after line clear has been granted to the station in rear.
- Exceptions:
- Where there is a continuous down gradient towards the station steeper than 1 in 260 between Distant and Home signal in single distant territory and between Inner Distant and Home Signal in Double Distant territories.
- The Home signal may be placed at a distance of sum of Block Overlap and Signal Overlap from BSLB (Block Section Limit Board) or the outermost Facing Point.
Other Signals
- Routing Signal: A Routing Signal shall be placed in rear of the Points, which it protects.
- Starter Signal: When one Starter Signal is provided for each converging line, it shall be so placed as to protect the adjacent running line or lines.
- Intermediate Starter Signal: An Intermediate Starter Signal shall be placed clear of fouling marks in rear of the points, if any, which it protects.
Slot Controls on Signals
- Where a signal is controlled through slots, it shall not be possible to take 'off' a signal unless all the controls have been exercised by the controlling agencies.
- Slot circuits shall be so designed that a slot once given is effective for only one train and a fresh slot has to be given for a subsequent train.
- Station Master's Slot Control on Reception & Dispatch signals.
Commissioning of Electronic Interlocking
- On completion of Outdoor signalling works and Electronic Interlocking works, System Integrity Tests (SIT) shall be done before commissioning.
- Drawings for Guidance on Installation are given at Appendix II.
- Maintenance Schedules are given at Appendix I for various signalling equipments.
Important Minimum Signalling Features
- Minimum signalling features shall be provided at various stations based on the standard of interlocking.
- The features include:
- Maximum permissible speed
- Isolation
- Point Operation, Locking, and Detection
- Train Detection
- MACLS Signalling, Movement authority
- Block Working
- Double Distant/Automatic Signalling
- Last Vehicle verification
- Relay/Electronic Interlocking
- Mobile Train Radio Communication (MTRC) or LTE or any other Technology
- ATP (ETCS/TCAS/TPWS) with Cab Signalling for SPAD mitigation
- Centralised Traffic Control (CTC)
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Description
This quiz covers the rules and aspects of combined railway signals, including stop, caution, attention, and proceed signals.