MACLS Signaling System Overview
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Questions and Answers

What type of signals shall be used for Main signals?

  • Colour Light multi-unit type (correct)
  • Single unit type
  • Position Light type
  • LED type only
  • In terms of signal location, where should signals normally be positioned?

  • Only above the applicable line
  • On the right side of the line
  • At any convenient location
  • On the left side or above the line (correct)
  • What is the minimum block overlap distance for multiple-aspect signalling?

  • 120 metres
  • 200 metres
  • 180 metres (correct)
  • 150 metres
  • Which of the following best describes the condition for non-operational signals?

    <p>They shall have two crossed bars and should not be lit</p> Signup and view all the answers

    What is a requirement for the visibility of signals to the loco pilot?

    <p>Signals should be well aligned for optimal visibility</p> Signup and view all the answers

    What must be avoided between lights of main signals and subsidiary signals?

    <p>Confusion between their aspects</p> Signup and view all the answers

    How must signalling uniformity be maintained at a station?

    <p>By conforming to the same type and standard for signals</p> Signup and view all the answers

    What should be considered when designing signal equipment?

    <p>The potential for outside interference</p> Signup and view all the answers

    What is the minimum adequate distance for two-aspect lower quadrant signalling?

    <p>400 metres</p> Signup and view all the answers

    What is the adequate distance required at stations equipped with multiple aspect signals?

    <p>180 metres</p> Signup and view all the answers

    How much signal overlap is required beyond an IB signal at a Class C station?

    <p>400 metres</p> Signup and view all the answers

    What is the minimum visibility distance for a Distant Signal?

    <p>400 metres</p> Signup and view all the answers

    What must occur before a Home signal can be taken ‘off’ on a double line?

    <p>The train must be at a stand at the Home signal.</p> Signup and view all the answers

    Which aspect does a Distant signal display to indicate 'Caution' in Single Distant Territory?

    <p>Two yellow lights in a vertical line</p> Signup and view all the answers

    What is required when the visibility of a Stop Signal cannot be obtained for 200 metres?

    <p>A speed restriction may be imposed.</p> Signup and view all the answers

    What is the minimum visibility distance for Inner Distant Signals?

    <p>200 metres</p> Signup and view all the answers

    What does a 'Proceed' aspect indicate on a Home signal?

    <p>One green light</p> Signup and view all the answers

    What is the adequate distance required when a train is to be received at a station with a sand hump or derailing switch?

    <p>120 metres</p> Signup and view all the answers

    Which of the following signals has a visibility requirement of 200 metres

    <p>All Stop Signals</p> Signup and view all the answers

    What must be true for a line to be considered clear on a single line scenario?

    <p>The last preceding train must have passed at least 400 metres.</p> Signup and view all the answers

    In double distant territory, what is the indication for the 'Attention' aspect?

    <p>Two yellow lights in a vertical line</p> Signup and view all the answers

    What must be done to display a less restrictive aspect in combined signals?

    <p>Line Clear must be obtained from the station ahead.</p> Signup and view all the answers

    What is the minimum distance a Distant Signal should be placed in Single Distant Territory from the first Stop Signal?

    <p>1 kilometer</p> Signup and view all the answers

    In Double Distant territories where Emergency Braking Distance is greater than 1.0 km, what should be the minimum distance for the second Distant Signal from the first Stop Signal?

    <p>2 kilometers</p> Signup and view all the answers

    When can the Home Signal be placed closer than 180 meters to the points it protects?

    <p>When there is a continuous down gradient steeper than 1 in 260</p> Signup and view all the answers

    What is the required distance for an Advanced Starter Signal from the outermost points in a Single Line section?

    <p>120 meters</p> Signup and view all the answers

    Which type of signal must be located at not less than 180 meters in rear of the gate it is protecting?

    <p>Gate Stop Signal</p> Signup and view all the answers

    What color and letter disc marker is provided for Distant and Inner Distant Signals?

    <p>White with 'P'</p> Signup and view all the answers

    What should the signal next in rear display if a Signal is displaying the 'Stop' aspect?

    <p>Caution</p> Signup and view all the answers

    If the caution aspect is being displayed and the adequate distance cannot be obtained, what must the next signal in rear display?

    <p>Attention</p> Signup and view all the answers

    For Metro Services, how is the placement of signals concerning the maximum emergency braking distance determined?

    <p>At the maximum permissible speed on the ruling gradient</p> Signup and view all the answers

    Which signal must be provided with a white colored disc with the letter 'IB' in black?

    <p>Intermediate Block Stop (IB) Signal</p> Signup and view all the answers

    What is the minimum spacing required for Automatic Block Signals from each other?

    <p>1 kilometer</p> Signup and view all the answers

    What aspect must a signal protecting diverging lines display when the points are set for a lower speed line?

    <p>Attention</p> Signup and view all the answers

    What does the home signal need to protect according to its placement criteria?

    <p>Connections on the line</p> Signup and view all the answers

    What is the purpose of the 'attention' aspect in signals?

    <p>To suggest that the train should reduce speed and prepare to stop.</p> Signup and view all the answers

    Under what conditions can combined signals be used?

    <p>Only under approved special instructions.</p> Signup and view all the answers

    How does a Calling-on signal function?

    <p>It signals the driver to stop short of obstruction.</p> Signup and view all the answers

    What is the color and position of the lights on a Shunt Signal when 'ON'?

    <p>White lights shown horizontally.</p> Signup and view all the answers

    What is required for a Calling-on signal to be taken 'OFF'?

    <p>Track circuits and a time delay must be activated.</p> Signup and view all the answers

    What type of route indicator is used for speeds exceeding 15 kmph?

    <p>Direction type with LED Matrix.</p> Signup and view all the answers

    Which of the following statements about Shunt Signals is incorrect?

    <p>They are always combined with Stop Signals.</p> Signup and view all the answers

    Which aspect is NOT provided by a combined Stop Signal under special instructions?

    <p>Approach.</p> Signup and view all the answers

    In which position does a Colour Light Calling-on signal display no light?

    <p>In the ‘OFF’ position.</p> Signup and view all the answers

    What factor determines whether a route indicator is required at diverging lines?

    <p>The number of diverging routes.</p> Signup and view all the answers

    How should Calling-on signals be placed relative to Stop Signals?

    <p>Below a Stop Signal.</p> Signup and view all the answers

    Which of the following is a requirement for Shunt Signals?

    <p>They must ensure level crossing gates are locked.</p> Signup and view all the answers

    What is the function of a Route Indicator when lines converge?

    <p>To indicate direction for clearing signals.</p> Signup and view all the answers

    What does a Shunt Signal indicate when it has no light displayed?

    <p>The signal is in the 'OFF' position.</p> Signup and view all the answers

    In the context of signals, which action is NOT permitted for a Calling-on signal?

    <p>Working simultaneously with a Stop signal.</p> Signup and view all the answers

    What is the primary requirement for Main signals in terms of type?

    <p>They shall be colour light multi-unit type.</p> Signup and view all the answers

    Which of the following statements correctly describes the positioning of signals?

    <p>Signals normally should be on the left or above the line.</p> Signup and view all the answers

    What is a requirement for equipment used in signalling?

    <p>They should be immune to outside interference.</p> Signup and view all the answers

    Which of the following describes the layer of functions supported by non-operational signals?

    <p>They must be turned away from the track.</p> Signup and view all the answers

    What should be avoided to prevent confusion between different signal types?

    <p>The aspect of one signal being similar to another.</p> Signup and view all the answers

    How should signalling uniformity be maintained across stations?

    <p>The type and standard should conform to maximum permissible speeds.</p> Signup and view all the answers

    What is a requirement concerning the visibility of subsidiary signals relative to main signals?

    <p>They should be less bright than main signals.</p> Signup and view all the answers

    What is the minimum block overlap distance required for Multiple Aspect Signalling?

    <p>180 meters.</p> Signup and view all the answers

    What is the minimum distance required for signal overlap?

    <p>120 metres</p> Signup and view all the answers

    What aspect does a Distant signal display for the 'Proceed' condition in Single Distant Territory?

    <p>Green light</p> Signup and view all the answers

    What must occur before the Home signal can be taken 'off' on a single line?

    <p>The line must be clear beyond the trailing points.</p> Signup and view all the answers

    Under approved special instructions, what may be deemed an efficient substitute for adequate distance?

    <p>A sand hump of approved design</p> Signup and view all the answers

    In case the visibility of a Stop Signal is below 200 meters, what action must be taken?

    <p>A speed restriction should be imposed.</p> Signup and view all the answers

    What is the minimum visibility distance for Distant Signals?

    <p>400 metres</p> Signup and view all the answers

    Which aspect indicates 'Caution' on a Distant signal in Double Distant Territory?

    <p>Two yellow lights in a vertical line</p> Signup and view all the answers

    What is the minimum required distance when a train is to be received at a Class C station on a single line?

    <p>400 metres</p> Signup and view all the answers

    What color and formation is displayed by Stop Signals for the 'Attention' aspect?

    <p>Two yellow lights in a vertical line</p> Signup and view all the answers

    What is the adequate distance referred to in signal regulations for a station equipped with multiple aspect signals?

    <p>180 metres</p> Signup and view all the answers

    What is the minimum distance for a second Distant Signal in Double Distant territories?

    <p>2 km from the first Stop Signal</p> Signup and view all the answers

    Under what condition can the Home Signal be placed closer than 180 meters to the points it protects?

    <p>If there is a continuous down gradient steeper than 1 in 260</p> Signup and view all the answers

    Which statement is true regarding the signal before a Home signal displays the 'Stop' aspect?

    <p>It must display a red light.</p> Signup and view all the answers

    What is indicated by a red light on a Stop signal?

    <p>Stop</p> Signup and view all the answers

    What is the primary purpose of a Routing Signal?

    <p>To protect the points it refers to</p> Signup and view all the answers

    What type of signal must be located at least 180 meters in rear of a gate it protects?

    <p>Gate Stop Signal</p> Signup and view all the answers

    What must be confirmed for line clear in two-aspect signalling?

    <p>The line is clear 400 metres beyond the home signal.</p> Signup and view all the answers

    Which signal indicates the 'Proceed' aspect?

    <p>Home signal</p> Signup and view all the answers

    What signal aspect is required if a signal protecting diverging lines is set for a lower speed?

    <p>Attention</p> Signup and view all the answers

    What color disc marker is used for Distant and Inner Distant Signals?

    <p>White with 'P'</p> Signup and view all the answers

    What is the minimum distance required for an Advanced Starter Signal from the outermost points in a Single Line section?

    <p>120 meters</p> Signup and view all the answers

    Which aspect must a signal display when the Distant Signal indicates 'Caution'?

    <p>Attention aspect</p> Signup and view all the answers

    What is the required spacing for Automatic Block Signals from each other under normal circumstances?

    <p>1 kilometer</p> Signup and view all the answers

    What does an Intermediate Block Stop (IBS) signal indicate?

    <p>A stop signal provided at an Intermediate Block post</p> Signup and view all the answers

    What marker is provided for the Gate Stop Signal?

    <p>Yellow disc with 'G'</p> Signup and view all the answers

    What shall the Distance Signal display to alert an approaching train to Stop?

    <p>Stop</p> Signup and view all the answers

    How are multiple aspect signals positioned concerning the next signal in advance when displaying 'Caution'?

    <p>Minimum of 1 kilometer</p> Signup and view all the answers

    When can a Calling-on signal be placed below any Stop Signal?

    <p>Under approved special instructions</p> Signup and view all the answers

    What does the 'C' marker on a Calling-on signal indicate?

    <p>Calling-on indication</p> Signup and view all the answers

    What are the light positions for the Position Light Shunt Signal when it is 'OFF'?

    <p>Two lights horizontal</p> Signup and view all the answers

    What aspect must a Stop Signal display when a Calling-on signal is taken 'OFF'?

    <p>Stop</p> Signup and view all the answers

    For which speed is a Direction type Route Indicator required for diverging lines?

    <p>For speeds in excess of 15 kmph</p> Signup and view all the answers

    What do all Shunt Signals lock and detect in their route?

    <p>All points, including isolation points</p> Signup and view all the answers

    What happens when a Shunt Signal is placed below a Stop Signal?

    <p>It cannot be worked at the same time</p> Signup and view all the answers

    Which of the following statements regarding the placement of Calling-on Signals is true?

    <p>They must be placed below a Stop Signal</p> Signup and view all the answers

    What aspect is NOT displayed by a Colour Light Calling-on signal when it is 'ON'?

    <p>No light</p> Signup and view all the answers

    Which signal should display 'Attention' when there is no adequate distance?

    <p>The immediate next signal in rear</p> Signup and view all the answers

    What must be ensured for a Calling-on signal to be taken 'OFF' for reception signals?

    <p>The train must have stopped after the Stop Signal</p> Signup and view all the answers

    What is required to be provided for controlling Shunt movements?

    <p>Shunt Signals exclusively</p> Signup and view all the answers

    What is the consideration for Route Indicators when lines converge?

    <p>Separate signals on separate posts are mandatory</p> Signup and view all the answers

    How should a Shunt Signal be positioned in relation to a Calling-on signal?

    <p>It must be below the Calling-on signal if both exist</p> Signup and view all the answers

    Study Notes

    Multiple Aspect Colour Light Signalling (MACLS)

    • All signals must be electrically lit and free from phantom indications.
    • Main signals are colour light multi-unit type, shunt signals are position light type. Calling-on signals may be included as needed.
    • Signalling should be uniform across stations & level crossings within a section, matching the maximum permissible speed. End-of-section signalling should also be uniform.
    • Signal number and height are limited to what's necessary for safety and operation.
    • Signals are normally placed on the left or above the line they control, unless specified otherwise. Right-side signals must have arrows pointing towards the applicable line.
    • Signals should be positioned for optimal view by train drivers and avoid confusion between signals or other lights. Subsidiary light sizes are smaller than main signals, and subsidiary signals should not be brighter.
    • All equipment should be designed, positioned, and secured to prevent outside interference.
    • Non-operational signals should be turned away from the track. Un-used signals are marked with two crossed bars (at least one meter long and 10cm wide). Un-used signals should not be lit.
    • Block overlap for multiple-aspect signalling shall be at least 180 meters.

    Signal Overlap & Distance

    • The minimum distance a train must be from a home signal (other than terminal stations) is calculated based on the type of signaling (double or single line) and the clear zone beyond the starter/trailing points.
    • Acceptable instances to remove the 'home' signal block include a train having come to a stop outside the signal, and confirmation the line is clear in the vicinity of the starter/trailing points.
    • Minimum distance required to remove the home signal depends on the type of signaling (minimum of 120m in MACLS).
    • A home signal cannot be moved until the line is clear for a designated minimum buffer, a sand hump or a derailing switch can be deemed a valid substitute.
    • Overlap beyond IB (Intermediate Block) signals (Class C station) is at least 400 meters beyond the IB home signal.

    Signal Visibility

    • Distant signals minimum visibility is 400 meters; adjustments for site constraints can be implemented (speed restrictions). Inner distant signals have a minimum visibility of 200 meters.
    • Stop signals have a minimum visibility of 200 meters; adjustments for site constraints can be implemented (speed restrictions).

    Signal Aspects

    • Signal aspects include Stop (red), Caution (yellow), Attention (double yellow), and Proceed (green) for various signals (Distant, Stop).
    • Specific aspects of Distant signals vary depending on whether the signal is in single or double distant territory, including aspects like double yellow and green and how Inner Distant signals will react.
    • Specific signal aspects illustrated in a table.

    Signal Placement

    • Distant signals are placed behind the first stop signal, with a minimum distance of one kilometer in single distant territory.
    • Double Distant territory may include a second distant signal at least 2 km from the first stop signal and an inner distant signal at least 1 km from the first stop signal, both with marker discs.
    • Home signals require a buffer of at least 180 meters from obstructions beyond the line of sight, with special considerations for gradients.
    • Intermediate Block (IB) signals have specific buffer distance requirements with a marker disc.

    Other Signal Types

    • Routing signals are placed behind the points they protect.
    • Starter signals, intermediate starter signals, advanced starter signals, and gate stop signals have specific placement, overlap and aspects criteria.
    • Automatic block signals require specific spacing and marker discs; they are spaced roughly 1 km apart (subject to other constraints).
    • Calling-on signals indicate caution to the driver and are placed below the stop signal. They operate with a delay to allow the train to stop.
    • Shunt signals control shunt movements and have specific aspect requirements & placement rules..
    • Combined signals can be used under specific conditions to show more than one signal aspect.
    • Diverging or converging lines have specific route indication requirements.

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    Description

    Explore the critical aspects of the Multiple Aspect Colour Light Signalling (MACLS) system used in railway operations. This quiz covers signal types, placement protocols, and safety measures to ensure effective communication for train drivers. Test your knowledge on the standards that govern railway signaling and its importance for operational uniformity.

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