Essentials of Signalling

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Questions and Answers

What does the Distant signal display for the 'Attention' aspect in Double Distant Territory?

Three yellow lights in a horizontal line

One yellow light and one green light

A single red light

Two yellow lights in a vertical line (correct)

In Double Distant Territory, what color light indicates 'Proceed' in the Distant signal?

Red light

Yellow light

Green light (correct)

Blue light

What additional requirement is there when combining a colour light Distant signal with a last Stop signal of a station in rear?

It can display a less restrictive aspect

It should flash red before clearing

It must display a yellow light with Caution

It must display the stop aspect until Line Clear is obtained (correct)

Which of the following aspects does the Inner Distant signal display in Double Distant Territory?

A yellow light (bottom) for caution, two yellow lights for attention, and a green light for proceed Signup and view all the answers

What is the aspect for 'Stop' in signal display?

A red light Signup and view all the answers

What is the requirement for a colour light Distant signal combined with an Intermediate Block signal?

It shall not display a less restrictive aspect than the stop aspect until Line Clear is obtained Signup and view all the answers

How are the yellow lights in the Distant signal configured for the 'Attention' aspect in Single Distant Territory?

Two yellow lights vertically aligned Signup and view all the answers

In a typical station within Double Distant Territory, which signal aspect indicates a train should 'Stop dead at Home'?

A red light Signup and view all the answers

What should be done if the inter-signal distance is less than the distance required for a warning board?

The signals in rear shall be controlled by the signal in advance or combined. Signup and view all the answers

Where is the warning board normally positioned according to standard procedures?

On the left of the line to which it applies, unless exceptions are made. Signup and view all the answers

What legend should be displayed on the indication board when approaching an unwarned stop signal?

Approaching unwarned Stop Signal Signup and view all the answers

When is an indication board with the legend 'Entering Token Territory' provided?

When approaching from a double line or tokenless block working section. Signup and view all the answers

In which scenario should a Shunting Limit Board be installed?

At Class 'B' stations over single lines without an Advanced Starter where shunting is allowed. Signup and view all the answers

What type of signalling change does an indication board inform Loco Pilots about?

Changes in type of signalling or block working. Signup and view all the answers

What is the purpose of the self-reflecting sheets or reflectors on a warning board?

To increase visibility in low light conditions. Signup and view all the answers

Which of the following scenarios requires the installation of an indication board at the First Stop Signal?

When approaching a station with automatic and absolute block working at opposite ends. Signup and view all the answers

What is the minimum distance for the First Stop Signal on Single Line sections from the outermost facing point?

The total of distances prescribed in GR. 8.01 and GR. 3.40 Signup and view all the answers

Under which circumstances do the provisions of Para no. 7.4.9 (a) apply?

Only at junctions equipped with signals Signup and view all the answers

Which of the following is a requirement for goods lines and sidings at their junctions with passenger lines?

Sand humps or trap points must be provided Signup and view all the answers

What is required at interlocked layouts regarding means of isolation?

They must be interlocked with relevant signals Signup and view all the answers

What is a distinguishing feature of block stations regarding non-isolated lines?

Track circuits or other appliances confirm line occupancy Signup and view all the answers

In the context of signalling, what is specified about the means of isolation on main or through lines?

Points for trap sidings must not be installed in the main line Signup and view all the answers

What aspect is given to the Loco Pilot of a run through train when a connected line is occupied at block stations?

A distinctive aspect restricting speed to 50 km/h Signup and view all the answers

What is NOT a condition for junctions where two block section lines meet?

The signalling system can be unapproved Signup and view all the answers

What is the initial setting of points leading to the Catch Siding once Line Clear is granted?

They are set for the main line. Signup and view all the answers

How should the interlocking of Catch/Slip Siding points with Block Instruments function?

The key is released once the siding points are set. Signup and view all the answers

Which condition must be met for setting the Points towards the Block section at a Double Line Station?

The block instrument must be set to 'Line Clear'. Signup and view all the answers

What is the purpose of the audible indication provided at the operation area of Points?

To indicate train receipt or despatch and when to normalize points. Signup and view all the answers

What should happen to shunting on non-isolated lines once Line Clear has been granted?

Shunting shall cease. Signup and view all the answers

What happens to the block instrument once the key is removed?

It gets locked in the last position. Signup and view all the answers

How are the take-off points of a Catch/Slip Siding set under normal conditions?

They are normally set and locked for the siding. Signup and view all the answers

What is required for a run-through train once Line Clear is granted?

All associated points must be set for the main line. Signup and view all the answers

What is the requirement for trains running through stations where isolation has not been provided?

Trains must comply with conditions outlined in the General Rules. Signup and view all the answers

How should speed restrictions for through running trains at a station be communicated?

By placing a speed restriction board at the first approach signal. Signup and view all the answers

In automatic territory with an emergency braking distance over 1.0 km, which signaling is mandated?

Four aspect automatic signaling. Signup and view all the answers

Which of the following actions is not permitted regarding trap sidings on through lines?

Inserting points for trap sidings without approval. Signup and view all the answers

What should be done if there is a differing speed restriction for through running trains at a station compared to neighboring stations?

Erect a speed restriction board at the first approach signal. Signup and view all the answers

What is a method of achieving isolation as mentioned in the regulations?

Providing a trap or short dead-end siding. Signup and view all the answers

What is the primary function of the devices and methods mentioned in mitigating a Train Passing Signal at Danger?

To prevent adverse effects after a train passes a danger signal Signup and view all the answers

Which statement regarding the isolation of goods receiving lines is true?

Goods receiving lines do not need to be isolated from one another. Signup and view all the answers

What is the general principle governing the speed of trains at junctions?

Speed is governed by general rules and the signals present. Signup and view all the answers

How should facing points be managed after the arrival of a previous train according to the guidelines?

Set to unoccupied line through Station Working Rules Signup and view all the answers

What should happen to signals and points in the event of a failure of connections and circuits?

They must remain at their most restrictive aspect and locked in position Signup and view all the answers

What are the two types of interlocking installations mentioned in the guidelines?

Route Setting and Non-route Setting Signup and view all the answers

Which control mechanisms are used for operating points and signals?

Relay and Electronic Interlocking Control Panels Signup and view all the answers

How should the display layout on the Control Panel be formatted?

Proportioned with distinct colors for each track circuit Signup and view all the answers

What may be provided based on the size and complexity of the yard?

Multiple Control Panels or Control Terminals Signup and view all the answers

What is true regarding the Control Cum Indication Panel (CCIP)?

It must display route switches and point switches in geographical order Signup and view all the answers

What indication is given by a disc type Shunting Permitted Indicator when shunting is not permitted during the day?

No light Signup and view all the answers

In which scenario should spring points be utilized according to the guidelines?

Only in exceptional cases Signup and view all the answers

What mechanism is required for operating a Shunting Permitted Indicator that works in conjunction with a Stop Signal?

Ground lever/EKT Signup and view all the answers

What is a necessary installation when spring points are operated in the facing direction?

Facing point locks Signup and view all the answers

What is the requirement for isolation at block stations allowing speeds greater than 50 kmph?

Total isolation from all connected lines required Signup and view all the answers

What type of light indication is used during the day when shunting is permitted according to the light type Shunting Permitted Indicator?

Yellow cross light Signup and view all the answers

What is required at block stations where trains run at speeds of 50 kmph or below concerning isolation?

Isolation not necessary Signup and view all the answers

Which of the following does NOT indicate that shunting is permitted?

Green light signal Signup and view all the answers

What is the minimum spacing required for Automatic Block Signals?

1 kilometer Signup and view all the answers

When a signal is displaying the 'Stop' aspect, what should the next signal in rear display?

'Caution' aspect Signup and view all the answers

What is the required adequate distance for placing a 'Caution' aspect signal from the next signal in advance?

1 kilometer Signup and view all the answers

If a signal protecting diverging lines cannot display the required aspect, what should be done?

Display 'Attention'/'Caution' aspect in the 'OFF' position Signup and view all the answers

What happens if the adequate distance for a 'Caution' aspect cannot be achieved?

Repeat the 'Attention'/'Caution' aspect back on successive signals Signup and view all the answers

Which aspect should be displayed by a signal next in rear when the points are set for a line other than the permitted higher speed line?

'Caution' aspect Signup and view all the answers

What color and letter are used on the marker for the IB Signal?

White 'IB' Signup and view all the answers

For every Multiple Aspect Signal required to display a 'Caution' aspect, what should be the normal placement distance?

At least 1 kilometer Signup and view all the answers

Under what circumstances may through running be permitted at stations?

When operationally required to receive trains from different directions simultaneously. Signup and view all the answers

What indication is displayed when non-interlocked points are set for the diverging line?

Edge of the disc by day and green light by night Signup and view all the answers

What minimum equipment is required for facing points that take off a running line?

A gauge tie plate and a facing point lock. Signup and view all the answers

Which of the following describes the indicators for Trap Points when they are closed?

Edge of the disc by day and green light by night Signup and view all the answers

What is the speed limitation requirement for trains passing over siding points with only minimum equipment?

A speed limit must be imposed, indicated with an 'S' marker and an indicator 30 metres away. Signup and view all the answers

What should be done to prevent trains from being stopped at a Stop Signal on a rising grade?

Implement approved special instructions under exceptional circumstances. Signup and view all the answers

Under special instructions, what indicator may be displayed at trap points where a misleading indication could occur?

White light Signup and view all the answers

What is the color of the Shunting Permitted Indicator when it allows uninterrupted movements?

Green Signup and view all the answers

What is required to ensure conflicts do not arise when using siding points on passenger running lines?

Interlocking with the block system in force. Signup and view all the answers

What indicates that siding points are set and locked for the running line?

Use of a key or suitable device to secure the bolting mechanism. Signup and view all the answers

Which type of indicator must be provided at all Trap Points on running lines that are not interlocked with signals?

Target type Signup and view all the answers

What color does the indicator show at non-interlocked points during the day when set for the straight line?

White Signup and view all the answers

Which condition applies to the insertion of points for trap sidings at main lines?

They shall be treated as derailing switches. Signup and view all the answers

What is the purpose of the Trap Indicators according to the provided specifications?

To show the status of Trap Points or derailing switches Signup and view all the answers

What necessity is imposed if the minimum equipment is provided for siding points?

A caution and termination indicator must be installed. Signup and view all the answers

At night, what does the Trap Indicator display when the trap points are open?

Red light Signup and view all the answers

Under what conditions can the Station Master's control over Home Signals be dispensed with?

Only if all reception lines are fully track-circuited. Signup and view all the answers

What is required before the Last Stop Signal can be taken 'OFF' while using Absolute block working?

Line Clear must be obtained from the block station ahead. Signup and view all the answers

How is a stop signal in the 'OFF' position automatically replaced to 'ON'?

By the passage of a train. Signup and view all the answers

What must be shown before a line can be closed and 'Line Clear' granted in relation to the First Stop Signal?

The 'ON' aspect of the relevant First Stop Signal must be proved. Signup and view all the answers

What additional condition affects the automatic replacement of a Starter Signal to 'ON' by the passage of a train?

If replacement glue and insulation joint is near the signal. Signup and view all the answers

What is one condition that must be met for the Assistant Station Master to operate the Points and Block instruments?

The line cannot be allotted by the Station Master. Signup and view all the answers

Which of the following is NOT a requirement for manually controlled signals to replace from 'OFF' to 'ON'?

Shall be replaced manually at all times. Signup and view all the answers

What is the function of the Last Stop Signal in relation to Block Working?

To restrict the movement until 'Line Clear' is received. Signup and view all the answers

What is the primary function of Train Protection Devices in the context of signal passing at danger?

To mitigate the adverse effects of a train passing a signal at danger. Signup and view all the answers

In the event of a failure of signal and interlocking circuits, what is the expected behavior of the related signals and points?

Signals remain at or return to their most restrictive aspect while points remain locked. Signup and view all the answers

Which type of interlocking installation operates based on the entry/exit principle?

Route Setting Type Signup and view all the answers

What is required for a Control Cum Indication Panel (CCIP) in signal operation?

Track circuits must be differentiated by color. Signup and view all the answers

How should facing points be positioned after the arrival of a previous train?

To an unoccupied line as stipulated in Station Working Rules. Signup and view all the answers

What should be implemented in installations based on size and complexity of operations?

Multiple Control panels or terminals with inter-slotting controls. Signup and view all the answers

What type of control panel is expected to replace a Control Panel in future installations?

Dual VDU in lieu of Control Panel and VDU. Signup and view all the answers

Which component is crucial for ensuring the fail-safe features of signals and interlocking circuits?

Regular maintenance and proper installation of connections. Signup and view all the answers

Study Notes

Essentials of Signalling

Multiple Aspect Colour Light Signalling (MACLS) is covered in this chapter. All signals must be electrically lit, free from phantom indications.
Main signals are colour light multi-unit type; shunt signals are position light type. Signal type may vary based on operational needs.
Signalling at all stations and interlocked level crossings in a section should have the same type and standard as per maximum permissible speed of the section. Signalling at both ends of a station should be uniform, as far as possible.
The number of signals and height should be limited to what is necessary for safety and operational requirements. Signals are normally placed on the left or above the line.
Signals should be positioned for the best possible view of their aspects by the loco pilot. Signals should be positioned to avoid confusion between aspects of different signals, and between subsidiary and main signals.
Electrical equipment should be designed to avoid external interference.
Non-operational signals should be clearly distinguished by two crossed bars across the signal. Signals not in use should not be lit.

Block Overlap

Block overlap should be at least 180 meters for multiple aspect signalling. The relevant extract of GR is provided.
Specific distance requirements are given for two-aspect lower quadrant signalling, two-aspect colour light signalling, multiple-aspect signalling, or modified lower quadrant signalling.

Signal Overlap

Signal overlap must be at least 120 meters.
The method of calculating 120-meter signal overlap is detailed and explained with GR text. This is related to taking the home signal "off."
Specific conditions relating to double-line and single-line circumstances are examined for operating the home signal.

Overlap Beyond IB Signal

The overlap beyond the IB signal (Class C station) should be at least 400 meters. The conditions for line being clear are detailed with GR text.

Visibility of Signals

Minimum visibility of distant signals is 400 meters; site constraints may allow for speed restrictions.
Minimum visibility of all stop signals is 200 meters; site constraints may allow for speed restrictions.

Aspects of Signals

Single Distant Territory signals display: a yellow light (bottom) for caution, two yellow lights vertically for attention, and one green light for proceed.
Double Distant Territory signals display: two yellow lights vertically for attention, and one green light for proceed for the distant signal display.

Placement of Distant Signal

Distant signals should be placed a suitable distance behind the first stop signal. This distance is at least 1 kilometer in single-territory, but can be longer in double-territory in certain circumstances

Placement of Stop Signals

Home Signals should be placed behind any train connections, given location restrictions for line obstruction after line clearance.
General guidelines on locating signals are included for double-line and single-line segments.

Subsidiary Signals – Calling-On Signal

A calling-on signal, when 'OFF,' instructs the loco pilot to cautiously approach an obstruction when the stop signal is 'ON.'
Calling-on signals do not have independent aspects in the "ON" position.
The 'OFF' position will display a yellow light.
Calling-on signals should be placed below the governing stop signal; this can be altered by approved instructions.

Subsidiary Signals – Shunt Signals

Shunt movements should be controlled by shunt signals.
Shunt signals should be position light type, white in the 'ON' position. Lights in the 'ON' position are horizontal, and in the 'OFF' position, they are tilted 45 degrees.
Shunt signals can be separate from, close to, or below other signals.

Warning Boards

A warning board to warn the loco pilot of an approaching stop signal should be at least 1.4 km behind the first stop signal.
Increased distance is permitted for gradient conditions.

Indication Boards

Indication boards provide warning signs about changes in type or location of block/signalling
When approaching an unwarned stop signal, a specific indication board should be present.
Approaching a block station or an absolute territory mandates a specific indication board.

Points, Operation, Indicators, and Isolation

Points are operated via point machines (approved types). Hand-operated points are allowed with electrical controls in some cases.
An obstruction test is used to ensure that points can be locked appropriately.
Point indicators (for non-interlocked points) must display a white target (by day) and white light (by night), directed straight forward for the positions given for those points.
Different indicators are used when points are for diverting rather than straight/forward lines.

Spring Points

Spring points primarily are for use under exceptional circumstances, where other provisions do not suffice.
Spring points, if facing a direction, must have facing point locks.

Means of Isolation

Isolation methods like sand humps, trap points are used for safety when setting up areas where trains and pedestrians or other objects are likely to intersect
Interlocked layouts' isolation provisions must work with the signals.

Interlocking of Signals with Points and Other Equipment

Signals, points, and other equipment must be interlocked to comply with certain essential conditions.
It must not be possible to turn off a main or subsidiary signal without all points and crossings in the route being properly locked.
Release of the route and unlocking of crossings should not occur until the signal is turned back on.

Control Panel

Control panel operation depends on the interlocking type. Types include route setting (based on entry/exit) and non-route setting (with individual point controls).
Operation of signals and points is from a control panel, or a control terminal (VDU) in electronic interlocking scenarios.
Multiple control panels (or VDUs) are permitted based on the complexity of related activities.
The layout (diagram) of the yard should be clearly displayed, and each track should have distinctive identification.

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Description

This quiz delves into the principles of Multiple Aspect Colour Light Signalling (MACLS) and the importance of standardization in railway signalling systems. It covers the operational needs regarding signal types, positioning, and the safety measures required for efficient locomotive operation. Test your knowledge on the essential aspects of railway signalling in this concise quiz.