Signal Sighting Guidelines Quiz
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Questions and Answers

What is the preferred minimum distance between a neutral section and a stop signal on a gradient of up to 1 in 300?

  • 200 meters
  • 400 meters
  • 1600 meters (correct)
  • 2500 meters

In what situation can the distance between a neutral section and a stop signal be reduced to 400 meters after the signal?

  • If it is unavoidable
  • If the gradient is 1 in 100
  • If the signal is not functioning
  • If PTFE type short neutral section is used (correct)

What is the minimum distance before a stop signal, according to the stipulations about PTFE type short neutral sections?

  • 400 meters
  • 1600 meters
  • 2500 meters
  • 200 meters (correct)

What additional guidelines must also be adhered to apart from the preferred distances mentioned?

<p>Stipulations from Railway Board &amp; RDSO (C)</p> Signup and view all the answers

What is the minimum horizontal distance from the center of the track to any structure as per the schedule of dimensions (SOD)?

<p>It is variable based on structure type (C)</p> Signup and view all the answers

What is the minimum distance for visibility of a Distant signal in MACLS territory?

<p>400 meters (B)</p> Signup and view all the answers

Which of the following locations should be avoided for placing a Stop signal?

<p>Steep gradients (A)</p> Signup and view all the answers

What is the required height for the normal aspect of a Colour Light signal?

<p>3.65 meters (D)</p> Signup and view all the answers

When should a Right Hand signal be provided with a retro reflective type of arrow?

<p>When proposed on Right Hand side (D)</p> Signup and view all the answers

In what situation should an Automatic signal not be placed according to the guidelines?

<p>In a Block section with heavy gradients (C)</p> Signup and view all the answers

What action should be taken if a signal is not in use?

<p>It should be distinguished by two crossed bars (D)</p> Signup and view all the answers

What distance should Intermediate block signals ideally split a block section into?

<p>Near halves (D)</p> Signup and view all the answers

What should be done to improve contrast if external light dominates a signal aspect?

<p>Provide a proper screen behind the signal unit (B)</p> Signup and view all the answers

What should be done if any signal post infringes with the schedule of dimensions?

<p>Paint the post with alternate Red &amp; white stripes. (D)</p> Signup and view all the answers

What is the minimum height at which a caution board should be provided if a signal post is within 2 meters of a live conductor?

<p>3 meters above rail level. (B)</p> Signup and view all the answers

In case color light Distant signals are used, which signals can they be combined with?

<p>With the last Stop signal in rear or an Intermediate Block signal. (B)</p> Signup and view all the answers

What color should each signal post be marked with for Normal Implantation?

<p>Black with white background. (C)</p> Signup and view all the answers

What is the purpose of locating the Intermediate Block (IB) signal away from the mid-section gate?

<p>To protect the level crossing gate. (B)</p> Signup and view all the answers

What should be done if a neutral section is provided after a stop signal?

<p>Ensure a sufficient distance from the signal to avoid stalling. (C)</p> Signup and view all the answers

What color marking indicates reduced implantation on a signal post?

<p>Red with white background. (A)</p> Signup and view all the answers

What material should be used to protect portions of a signal post that are near a live conductor?

<p>Iron screening. (C)</p> Signup and view all the answers

What is the height range for alterations from rail level to 305 mm above rail level?

<p>1675 mm to 1905 mm (C)</p> Signup and view all the answers

What is the maximum level for alterations from 305 mm above to 3355 mm?

<p>2135 mm (A)</p> Signup and view all the answers

Which height indicates a decrease in levels from 3355 mm above rail level?

<p>1980 mm (B)</p> Signup and view all the answers

What alteration height is indicated for the range from 3735 mm above rail level to 4420 mm?

<p>2135 mm (A)</p> Signup and view all the answers

For alterations below rail level up to formation level, what is the height indicated for curves with a radius less than 875 m?

<p>2725 mm (B)</p> Signup and view all the answers

What is the alteration amount when moving from 4420 mm to 4610 mm above rail level?

<p>250 mm (A)</p> Signup and view all the answers

Which option represents the total alteration height from 4115 mm above rail level to 6250 mm?

<p>1600 mm (C)</p> Signup and view all the answers

What is the alteration height range for works below rail level up to formation level for straight tracks?

<p>2725 mm to 2575 mm (B)</p> Signup and view all the answers

What is the purpose of the Current probe C2 in the fall of potential method?

<p>To be placed away from the electrodes under test (A)</p> Signup and view all the answers

How far should the first potential probe, P1, be from the earth electrode(s) under test?

<p>30 to 60 meters (B)</p> Signup and view all the answers

What must be the depth of the probes C2 and P2 when driven into the earth?

<p>15 to 30 cm (A)</p> Signup and view all the answers

What should be done if the three readings of earth resistance show significant variation?

<p>Shift the location of probe C2 farther away (A)</p> Signup and view all the answers

What is the significance of comparing the three readings in this method?

<p>To confirm consistent resistance measurements (C)</p> Signup and view all the answers

In the fall of potential method, what happens if all three readings are significantly different?

<p>The test is deemed invalid (B)</p> Signup and view all the answers

What is the first measurement taken in the fall of potential method referred to as?

<p>Reading 1 (C)</p> Signup and view all the answers

Which action is performed after measuring Reading 1?

<p>Move probe P2 3 meters farther away (A)</p> Signup and view all the answers

Flashcards

Signal Location Factors

Considerations for positioning signals, including avoiding risky locations and ensuring proper visibility.

Signal Visibility

Minimum distances for visibility of distant and stop signals, particularly in the MACLS territory.

Signal Height

Normal height of color light signals is approximately 3.65 meters.

Signal Contrast

External lights should not obscure signals. Screens may be necessary for better contrast.

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Intermediate Block Signal Placement

Splitting the block section almost equally and avoiding heavy/steep gradients, unless adequate braking is possible

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Automatic Signal Spacing

Automatic signals should generally be placed 1 km apart, but spacing can vary based on conditions.

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Right-Hand Signals

Signals on the right side of the track require approval and use retro-reflective arrows.

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Signal Inactivity Marking

Signals out of service should be marked with crossed bars to avoid confusion.

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Neutral Section Stop Signal Distance

The distance between a neutral section and a stop signal must be enough to prevent a train from crossing the signal while coasting through the neutral section.

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Preferred Distance (Gradient ≤ 1 in 300)

For gradients up to 1 in 300, the recommended distance between a neutral section and a stop signal is 1600 meters.

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Preferred Distance (Gradient > 1 in 300)

For gradients steeper than 1 in 300 and up to 1 in 200, the recommended distance between a neutral section and a stop signal is 2500 meters.

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Short Neutral Section Distance Reduction

If a PTFE type short neutral section is used, the distance between the stop signal and the neutral section can be reduced to at least 400 meters after the signal and 200 meters before the signal.

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Track to Structure Minimum Distance

The minimum distance from the center of the track to any structure must adhere to a predefined schedule, often considering safety and maintenance.

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Signal Proximity

Signals located close together can be combined for efficiency, following approved guidelines.

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IB Signal Placement

Intermediate Block signals should be placed near mid-section gates to protect level crossings in train operation systems.

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Signal Post Dimensions

Signal posts must maintain minimum horizontal distances from tracks, marked appropriately for normal/reduced implantation.

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Signal Post Marking

Signal posts are marked with their center-to-center distance to the track(s) using either black/white or red/white, depending on the installation requirements.

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Infringing Signal Posts

Signal posts that infringe on prescribed dimensions should be marked with red/white stripes and clear markings to indicate the infringing track(s).

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Signal Post Protection (High Voltage)

Signal posts near high voltage lines (25 KV) must be appropriately protected by screening or caution notice.

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Signal Post and Neutral Section Distance

Neutral sections should be away from stop signals and level crossings. Enough distance from a stop signal must exist to allow the train to safely pick up speed after stopping to pass the neutral section without risk of stalling.

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Caution Board Height

If a signal post portion falls within 2 meters of a 25KV live conductor, a caution board should be placed on the signal post at 3 meters above the rail level.

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Earth Resistance Measurement

The process of determining the resistance of an earth electrode using a four-terminal earth tester and the 'Fall of Potential' method.

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Four-terminal Earth Tester

A device used to measure earth resistance, consisting of four terminals for connecting probes to the earth electrode, current source, and potential points.

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Fall of Potential Method

A technique used to measure earth resistance by measuring the potential difference between two points along a current flow path through the earth.

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Probe Placement

Strategic positioning of probes for accurate earth resistance measurement. Current probes are placed near the electrodes and at a distance, while potential probes are placed between them.

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Multiple Earth Electrodes

Measurements involving multiple earth electrodes, such as a ring earth system, require adjusting probe placement to ensure accurate readings.

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Consistent Readings

Reliability of earth resistance measurements depends on obtaining similar readings when moving the potential probe. If readings vary significantly, adjust probe placement.

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Average Calculation

Calculating the average of multiple earth resistance readings obtained with different potential probe positions to achieve a more accurate estimate.

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Significant Variation

If the earth resistance measurements vary significantly, it indicates an issue with probe placement or the earth connection. Reposition probes and repeat the test.

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Signal Height (Existing Works)

The standard height of signal lights in existing works is 3.65 meters above rail level.

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Signal Height (New Works)

For new works, the standard height of signal lights is 1.905 meters (1905 mm) above rail level.

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Signal Height Alterations

Signal height adjustments are made based on the height above rail level specified in each case.

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Signal Placement (Below Rail Level)

For straight tracks and curves with a radius greater than 875 meters, signals are placed 2575 mm below rail level.

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Signal Placement (Tight Curves)

For curves with a radius less than 875 meters, signals are placed 2725 mm below rail level.

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Signal Placement: Straight Tracks

On straight tracks, signals are generally placed below rail level up to formation level, depending on the radius of the track.

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Signal Spacing (New Works)

The spacing between signals in new works depends on the height above rail level. For example, a 1905 mm signal might have a spacing of 1600mm.

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Signal Spacing (Existing Works)

In existing works, the spacing between signals depends on the height above rail level. For example, a signal 1.675 meters above rail level might have a spacing of 1905 mm.

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Study Notes

Signal Sighting Guidelines

  • Factors to consider for signal placement:
    • Refer to SEM paragraphs 7.1.13 and 7.1.14
    • Avoid signals in risky areas (steep grades, bridges, culverts, obstructions, theft-prone areas, chemical factories)
    • Maintain minimum visibility: 400 meters for distant signals, 200 meters for stop signals. Refer to paragraph 7.1.11
    • Normal signal height should be approximately 3.65 meters
    • Avoid external lights dominating signal aspect; use screens if needed for contrast improvement
    • Intermediate block signals should split block sections roughly in half
    • Don't install intermediate block signals in sections with steep gradients of more than 1 in 80 unless train brake power is adequate for stopping at the signal.
    • Automatic signals should be spaced approximately 1 km apart, except in sections with steep gradients of more than 1 in 80 where adequate brake power for stopping at each automatic signal is needed.
    • Right-hand signals require prior approval and should have a reflective arrow indicating the pertinent track.
    • Signals should be turned away from traffic during testing and placement before initial use, but not blocked.
    • Crossed bars should be visible on signals not in use to clearly indicate this.
    • Signals not in use shouldn't be illuminated
    • Signals in close proximity can be combined according to paragraph 7.1.16
    • A distant signal can be combined with the station's last stop signal, an intermediate block signal, or a level crossing stop signal (refer to GR 3.07(7), G.S.R. 157(E), dated 05-03-21)
    • If an intermediate block signal and a gate are nearby, the block signal should protect the gate as well

Schedule of Dimensions (SOD)

  • Minimum horizontal distance between a structure and a track center should follow SOD guidelines. See Annexure 19-A2 for details.
  • Every signal post should have its center-to-center distance to the track clearly marked. Signal posts and components not aligned with the specified dimensions should be marked with alternating red and white stripes at the eye level of a locomotive driver, pointing towards the affected track
  • Signal post locations and fitting locations should be at least 2 meters away from 25 kV live conductors, with appropriate screening or cautionary boards mounted to the signal post if they are within this range.
  • Provisions for neutral zones, separating signals from level crossings, and adequate distances for train coasting through neutral zones without stalling are necessary.

Measurement of Earth Resistance

  • The method for measuring earth resistance uses a "fall of potential" method with four terminals.
  • Steps include connecting current and potential probes to the earth electrode(s) under test and driving probes into the ground at various distances and depths.
  • Measurements are taken at different positions, and the average of these readings are used to determine earth resistance.
  • If variations are large, the test location of probes should be adjusted and the testing repeated.

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Signal Sighting Guidelines PDF

Description

Test your knowledge on the guidelines for signal placement in railway systems. This quiz covers essential factors like visibility, height, and spacing of signals based on specific conditions. Refer to the SEM for technical details as you answer each question.

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