Mechanical Signalling Equipment Maintenance

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Questions and Answers

What is the primary reason for periodically moving and shifting the worn-out portion of signal wire over pulley wheels?

To improve the alignment of the wire

To prevent excessive wear at one point (correct)

To reduce the risk of electrical shock

To prevent corrosion of the wire

What should be done to kinked signal wires?

Replace them immediately

Leave them as they are

Straighten them (correct)

Remove them and dispose of them

Who is responsible for cleaning signal glasses, roundels, and lenses of kerosene lit signals?

Traffic staff (correct)

Railway Engineers

Signal staff

Station Master

Who is responsible for cleaning signal lamps?

The operating staff Signup and view all the answers

How often should interlocking frames, interlocking key boxes, and Station Master's Slide Control frames be overhauled?

Once in three years Signup and view all the answers

What should be done to bent pulley stakes?

Straighten them Signup and view all the answers

What is the purpose of periodically examining and replacing signal and indicator lamps?

To ensure proper functioning of signals Signup and view all the answers

At which frequency should Relay interlocking and Electronic interlocking installations be tested?

As indicated in SEM Chapter 21 Signup and view all the answers

In stations with dense traffic and high speeds, what can the Railways prescribe?

More frequent inspections Signup and view all the answers

Who is responsible for testing the working of signals fitted with electric repeaters?

The SSE/JE (Signal) Signup and view all the answers

Where can the type, provision, placing, and indication of Point, Trap and Shunting Permitted Indicators be found?

Chapter 7 of SEM Signup and view all the answers

What should be done to damaged or corroded signal wires?

Renew them Signup and view all the answers

Who is responsible for cleaning roundels of electrically lit signals?

Signal staff Signup and view all the answers

What should be ensured for signal wires running under the track?

They do not drag on the ground or rub against the ballast Signup and view all the answers

What is the recommended maintenance schedule for mechanical signaling equipment?

As prescribed in Annexure: 12-MS1 Signup and view all the answers

How often should records of interlocking frame overhauls and tests be maintained?

Periodically once a year Signup and view all the answers

What is the condition for showing at least one back light in the 'ON' position in Distant Signals in Multiple aspect area?

The arrangement is such that the bottom light is lit only when the arm is displaying the 'attention' aspect Signup and view all the answers

Who is responsible for arranging the trimming of tree branches or cutting of trees within the Railway boundary if they interfere with the Loco Pilot's or cabin man's sighting of signals?

SSE/JE (Signal) Signup and view all the answers

What is the purpose of providing an artificial background to signals?

To improve the sighting of signals Signup and view all the answers

What is the minimum distance that an arm provided with an artificial background should project beyond?

150 mm Signup and view all the answers

What should be kept plumb and in good repair?

Signal posts Signup and view all the answers

What should be inspected to detect decayed or loose boards?

Deck boards Signup and view all the answers

Who is responsible for providing signal dubbers and kerosene whenever kerosene lit signals are provided?

Traffic staff Signup and view all the answers

What should be replaced if found to be decayed or loose?

Deck boards Signup and view all the answers

What is the primary concern when it comes to counterweights in signaling systems?

They should be firmly secured and in their correct position Signup and view all the answers

What is the purpose of co-acting signals in a signaling system?

To provide a duplicate signal where the main arm or light is not in view Signup and view all the answers

What is the minimum distance requirement for a Distant Signal from the First Stop Signal?

1 kilometre Signup and view all the answers

What is the minimum distance required between a Shunt Signal and a main line signal when they are placed on the same post?

2.5 meters Signup and view all the answers

What is the shape of the Semaphore arm of a Stop Signal?

Square ended Signup and view all the answers

What is the purpose of a slot lever in a signaling system?

To prevent the Warner arm from being taken 'OFF' unless the Stop Signal is at 'OFF' Signup and view all the answers

What is the requirement for back lights on Distant Signals in a multiple aspect area?

Two back lights in the 'ON' position and no light in any other position Signup and view all the answers

What is the color of the front of the arm of a Distant Signal?

Yellow Signup and view all the answers

What is the indication of a Distant Signal by night when displaying the 'Attention' aspect?

Two yellow lights in a vertical line Signup and view all the answers

What is the correct position for balance levers in signaling systems?

Parallel to the line and out of reach from the ground Signup and view all the answers

What is the purpose of a Distant Signal?

To provide a warning to the driver of an approaching signal Signup and view all the answers

What is the requirement for the fixed green light of a Warner Signal?

It should show a back light only when the arm is in the 'ON' position Signup and view all the answers

What is the angle of the Semaphore arm of a Distant Signal when displaying the 'Caution' aspect by day?

Horizontal Signup and view all the answers

What is the primary concern when it comes to spectacle roundels or glasses in signaling systems?

They should be attended to and replaced promptly if found loose, cracked or broken Signup and view all the answers

What is the color of the back of the arm of a Distant Signal?

White Signup and view all the answers

What is the requirement for the lock nuts on adjustable joints in signaling systems?

They should be tight to ensure the signal remains in place Signup and view all the answers

How often should assembled interlocking bars be checked and tested?

In accordance with approved Locking Diagram Signup and view all the answers

What is the purpose of marking plungers, interlocking bars, and locks in a mechanical signalling system?

For ease of identification Signup and view all the answers

What is the maximum allowed movement of a lever block in a locking system?

12 mm Signup and view all the answers

What is the primary concern when designing a locking system in mechanical signalling?

Durability and accuracy Signup and view all the answers

When should the release locking be effected in an interlocking system?

After the completion of the movement of the lever Signup and view all the answers

What is the purpose of providing a carrier lock or dummy pieces in certain interlocking bars?

To accommodate over 10 levers in SA 1101 Lever Frame Signup and view all the answers

What is the recommended method of attaching a top piece to a plunger in a mechanical signalling system?

Riveting Signup and view all the answers

What is the purpose of locking strips in a mechanical signalling system?

To comply with approved plans Signup and view all the answers

According to the approved drawings and specifications, what should be marked with identifying letters or figures?

Standards, quadrants, quadrant supports, levers shoes, locking boxes, and covers Signup and view all the answers

What is the correct procedure for assembling mechanical locking?

In accordance with approved Locking Diagram Signup and view all the answers

What should be done to ensure proper alignment of locking boxes?

They should be correctly aligned Signup and view all the answers

What should be checked for proper fit with no slackness?

Only pin joints Signup and view all the answers

What should be marked on plungers?

The relevant lever number and the number of the 'locking' box Signup and view all the answers

What should be done to ensure that interlocking frames conform to specifications?

They should be constructed according to approved drawings Signup and view all the answers

What should be obtained before making any alterations to the locking system?

Approval from the relevant authorities Signup and view all the answers

How should mechanical interlocking locks be marked?

With their respective lever number and the number of the channel of the locking box Signup and view all the answers

When testing a locked lever, what should be applied to ensure it is not free before the releasing lever has completed its travel?

A steady pressure Signup and view all the answers

What should be prepared to facilitate testing of large interlocking frames?

Test charts Signup and view all the answers

What is considered to have too much lost motion when a lever or catch handle can be moved more than the allowance stipulated?

A lever with excessive movement Signup and view all the answers

What should be tested on the same principle as before when a lever is released by a special combination?

Each part of the combination Signup and view all the answers

What should be ticked off on the interlocking table as each lock is tested?

The figures of the lock Signup and view all the answers

What should be tested whenever possible, along with each lock?

The reciprocal lock Signup and view all the answers

What should be applied to a locked lever to ensure it is not free before the releasing lever has completed its travel?

A steady pressure Signup and view all the answers

What is the purpose of testing each lock and its reciprocal?

To ensure that all locks are properly tested Signup and view all the answers

Who is responsible for checking the components of a new interlocking frame on receipt?

SSE/JE (Signal) Signup and view all the answers

How should interlocking frames be erected?

According to the approved plans and locking fitted in accordance with the approved Locking Diagram Signup and view all the answers

What should be done after carrying out additions and alterations to interlocking frames?

Locking should be checked completely Signup and view all the answers

What should be quoted when requisitioning new plungers?

Correct drawing number and if that is not available, state the type of frame and length of plunger required Signup and view all the answers

What should be specified when requisitioning new mechanical interlocking locks (dogs)?

Type number shown against each lock on the standard drawings Signup and view all the answers

How should locking be checked after assembling?

Completely against the approved Locking Diagram Signup and view all the answers

What should be done to the covers after assembling locking?

They should be padlocked and sealed Signup and view all the answers

What is the purpose of checking locking after assembling?

To ensure it is in accordance with the approved Locking Diagram Signup and view all the answers

What should be examined to ensure there is no lost motion in Lockbars?

Driving pieces Signup and view all the answers

Under what condition can Lockbars be installed over a check rail portion?

Only if other electrical means cannot be provided Signup and view all the answers

How often should Lockbar clips be fixed to the rails?

At the end of the Lockbar Signup and view all the answers

What should be kept in good order to ensure Lockbars fit close to the rail?

Arms and pins of clips Signup and view all the answers

What should be done to ensure Lockbars are kept straight and true?

Examining the driving pieces Signup and view all the answers

How should Lockbars be installed in relation to the top of the rail?

Practically level with the top of the rail Signup and view all the answers

What should be done to ensure the end of the Lockbar is properly positioned?

Keeping the Lockbar 25 mm clear of the toe of the switch Signup and view all the answers

What should be provided to ensure the Lockbar fits close to the rail?

At least 12 clips and 3 stops Signup and view all the answers

Study Notes

Maintenance of Signal Wire Run (Single Wire)

All wire runs shall be maintained in proper level and alignment
Damaged wire or wire rope showing signs of corrosion or rusting shall be renewed
Kinked wire shall be straightened and bad joints removed
Wire shall be periodically moved and worn out portion shifted off the pulley wheel to prevent excessive wear over pulley wheels at one point
Wires running under the track shall neither drag on the ground nor rub against ballast, base of rails or side of sleepers

Maintenance of Pulley Stakes and Pulleys

Brackets of pulley wheels shall be examined to see that they are securely fixed and that the wheels revolve freely
All damaged, broken and missing pulley wheels or brackets shall be renewed promptly
Bent pulley stakes shall be straightened and worn-out ones replaced

Maintenance of Electrical Repeaters and Signal Lamps/LEDs

The SSE/JE (Signal) shall test the working of the signals fitted with electric repeaters when making their periodical inspection and see that they are in proper adjustment
All Signals (oil lit and electrically lit) and Point and Trap Indicator lamps shall be examined regularly and any lamps or founts found defective shall be replaced promptly

Cleaning of Signal Glasses and Lamp Lenses

The Traffic staff are responsible for wiping and cleaning of signal glasses, roundels, and lenses of kerosene lit signals
Roundels of electrically lit signals shall be cleaned by signal staff

Maintenance of Point, Trap and Shunting Permitted Indicators

Point, Trap and Shunting Permitted Indicators shall be provided in accordance with the approved plans
Type, Provision, Placing and Indication of these indicators are covered in detail in Chapter 7 of SEM

Maintenance Schedule

The maintenance schedule for various items of 'Mechanical signalling equipment shall be as in Annexure: 12-MS1
At stations having dense traffic and high speeds, the Railways may prescribe more frequent inspections, if considered necessary

Overhauling and Testing of Interlocking Mechanical/Electromechanical

All interlocking frames, interlocking key boxes and Station Master's Slide Control frames shall be overhauled once in three years and tested periodically once in a year
Relay interlocking and Electronic interlocking installations shall be tested as indicated in SEM Chapter 21

Trimming of Trees Obstructing Visibility

Where trees interfere with the Loco Pilot's or cabin man's sighting of signals, the SSE/JE (Signal) shall arrange with the SSE/JE (Works) for Trimming of tree branches or cutting of trees within the Railway boundary

Artificial Backgrounds and Posts

Signals may be provided with an artificial background painted white, if found necessary to improve the sighting or when the background is a bridge or structure
Arms provided with an artificial background shall project 150 mm beyond or be provided with a tell tale arm so that it can be seen by the Station Master
Signal posts shall be kept plumb
Signal post guys, where provided shall be kept tight and in good repair

Deck Boards and Signal Dubbers

Deck boards on bracket posts and gantries shall be inspected to detect decayed or loose boards
Missing or defective boards shall be replaced
Signal dubbers and kerosene shall be provided by Traffic staff
Counterweights are in their correct position and firmly secured and that the lock nuts on adjustable joints are tight

Slotting

Where signals are slotted, any of the controlling agencies shall be independently capable of returning the signal to 'ON'

Shunt Signals and Balance Levers

Where a Shunt Signal is placed on the same post as a main line signal, it shall be placed not less than 2.5 meters below the main arm
Balance levers shall be placed out of reach from the ground and parallel to the line
Counterweights shall be securely fastened to the levers and safety bolts provided at the end of the levers

Interlocking Frames and Components

Interlocking frames shall conform to approved drawings and specifications.
Plungers, interlocking bars, and mechanical interlocking locks (dogs) shall be marked with identifying letters or figures.
Locking boxes shall be correctly aligned, and all pin joints shall be made a proper fit with no slackness.

Assembling Mechanical Locking

Mechanical locking shall be assembled in accordance with approved Locking Diagram.
Approval shall be obtained for any alteration, constructional or technical, found essential during the course of assembling locking.
Locking boxes shall be correctly aligned, and all pin joints shall be made a proper fit with no slackness.

Testing and Checking

Each assembled interlocking bar shall be checked and tested to ensure it is in accordance with approved Locking Diagram.
The locking provided through each bar shall be in accordance with approved interlocking table.
The lost motion of a lever, which is locked, shall be such that the lever block cannot be moved more than 12 mm over the lever quadrant.
The locking shall be strong, durable, and accurate, and it shall not be possible to force the locking.

Installation, Testing, and Maintenance

Interlocking frames shall be erected in accordance with approved plans and locking fitted in accordance with the approved Locking Diagram.
The locking shall then be carefully checked and compared with the approved Locking Diagram and tested by pulling of individual levers against the approved Interlocking Table.
Any additions and alterations to interlocking frames shall be carried out only in accordance with the approved revised plans and interlocking tables.

Lockbars

Lockbars shall be so installed that with the operating lever normal, an outside Lockbar lies practically level with the top of the rail, and an inside Lockbar lies 38 mm below the top of the rail.
Each Lockbar shall be provided with not less than twelve clips and three stops located in such a manner that the maximum inter clip distance is 1220 mm.
Lockbars shall not be installed over a check rail portion as a matter of course, except under special circumstances and only if other electrical means cannot be provided.

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Description

Learn about the maintenance of signal wire runs, including alignment, wire condition, and joint repair. This chapter covers the essential procedures for ensuring mechanical signalling equipment operates safely and efficiently.