77 Questions
What is the purpose of Audible Indicators in Non-Co-operative type Instruments?
To warn the receiving station when the train has passed the Home Signal
What is the function of 'Train On Line' in Non-Co-operative type Instruments?
To ensure the instruments are set to 'Train On Line' position automatically
What is the purpose of Shunting Keys in Non-Co-operative type Instruments?
To provide authority for shunting in the block section
What is the purpose of Track Circuits or Axle Counters in proving Block Section to be Clear?
To prove the block section to be clear
What is the purpose of the indicator in each block station?
To show whether the block section is occupied or not
When is the instrument set to 'Line Closed' condition?
When the train has passed the Home Signal at the receiving station
What is the purpose of the Audible Indicator in instruments?
To warn the receiving station when the train enters the block section
What is the purpose of the 'Train On Line' and Audible Indicator in Non-Co-operative type Instruments?
To warn the receiving station when the train enters the block section and indicate when the block section is occupied
What is the maximum induced voltage allowed due to power line parallelism?
150 V
What is the purpose of block filters in block instruments?
To ensure PR relay immunity
Under what condition is the use of single line push button token less block instruments permitted?
In sections with parallelism not exceeding 1.5 km
What is the minimum depth required for burying an earth?
1.5 meters
What is the maximum resistance allowed for an earth?
10 ohms
Why is a separate earth not required for block instruments working on metallic return?
Because they are exempt from earthing requirements
What is the minimum distance required between two earths?
2.5 meters
Where should the protective earth for SPDs of block instruments be connected?
To a common ring earth of Indoor Signalling system
What should the loco pilot do till he reaches the advance station?
Proceed at restricted speed
What is a condition for taking off IBS in double line?
Line clear has been obtained from Block Station in advance
What should be done before establishing the direction of traffic in single line?
Line clear should be obtained from Block Station in advance
What is a consideration for locating IB Signals?
Split the block section into near halves
What should be done before taking off IBS in single line?
Line clear should be obtained from Block Station in advance
What is an example of a method of providing IB signals?
Using Optical Fiber Cable (OFC) and Multi Section Digital Axle Counter (MSDAC)
What is a condition for IBS in double line?
IBS should be interlocked with any means of block working
What should be avoided when providing IB signals?
Providing IB signals in block sections with steep falling gradients
What is the title of the layout plan mentioned in 18-D1?
IB Hut Layout Plan (Double line/Single line)
What is the component mentioned in 18-D4?
Filter Unit
What is the color of the metal casing in Double Line Block Instruments?
Green Enamel
What is the type of Block Instruments mentioned in the painting scheme?
Double Line Block
What is the color of the body in Single Line Tokenless Block Instrument of Push Button Type?
Grey Enamel
What is the primary purpose of the Level-1 automatic reset arrangement?
To reset the failed track section using the clear track section information
What is the condition for automatic resetting with supervisory track sections?
When the supervisory track section is clear and the track section is in failure state
What is the purpose of keeping the reset track section in preparatory mode in Level-2 reset?
To allow the train to enter the track section with low speed
What is the purpose of DN-SPT supervisory track section?
To reset all track sections in the DOWN direction
What happens when a train with low speed enters and exits the track section with equal count at the boundaries of track section?
The signal turns 'ON'
What is the purpose of Level-3 reset arrangement?
To manually reset all failed track sections in the section
What is the condition for manual resetting with Level-3 reset?
When the Level-1 and Level-2 reset arrangements fail
What is the primary purpose of the track section in Level-1 reset arrangement?
To provide clear track section information
What is the responsibility of the Senior Section Engineer (Signal) regarding the register of Block Instruments?
To maintain a register containing the type of instrument, its serial number, location, and name of manufacturer.
What should be done to tokens that are cracked or deformed or have worn to a size smaller than the normal size?
They should be removed and broken up and returned to Stores.
What should the Sectional JE/SSE (Signal) do at least once in six months?
Take a census of the tokens working in various block sections.
What should be done to a token so removed from service?
It should be replaced with another token of the same number.
When a token is lost and cannot be found after a thorough search, who issues a joint circular to cancel the lost token?
Senior Divisional/Divisional Signal and Telecommunication Engineer
Where should the record of token census be kept?
In the Signal History Book at every station.
What is the purpose of the 'Token Balance Book' maintained by Technicians in charge of single line token instruments?
To keep track of token accumulation and balancing
What should be done to advice regarding tokens that have been removed?
It should be given to all concerned.
What happens to a lost token if it is found after six months?
It is broken and returned to stores
Who endorses the 'Token Balance Book' before it is issued to Technicians?
Senior Section Engineer (Signal)
What should be checked when the train enters the block section?
That the Last Stop Signal is automatically replaced to 'ON'.
Why is a token replaced with a token of next higher number in continuation of the series in use on the section?
Because the token is not found for six months
What should be checked when the commutator is turned from 'Line Closed' position to 'Train On Line' position?
That the commutator is free for return to 'Line Closed' position.
Where are the particulars of lost tokens exhibited?
Near the relevant instrument
What is the purpose of transferring tokens from one instrument to another?
To balance tokens in the section
What is the duration after which a lost token is replaced with a token of next higher number in continuation of the series in use on the section?
Six months
What is the primary advantage of using Multi Section Digital Axle Counters (MSDACs) in track detection and exchange of signaling information?
Minimizing signaling and quad cables with no RE cut sections
What is the main drawback of conventional IB signaling without duplication?
It is prone to intermittent failures, making the system less available
What is the purpose of providing axle counters for track vacancy detection in rear and advance sections?
To detect track vacancy in rear and advance sections
How does the scheme with dual MSDAC for detection of track vacancy achieve reliable working?
By minimizing signaling and quad cables with no RE cut sections
What is the primary advantage of using Multiplexing facilities of MSDAC for exchange of signaling information?
It enables the exchange of signaling information between two locations
Why are location boxes in inaccessible locations a problem in conventional IB signaling?
They are difficult to maintain and attend to failures
What is the primary purpose of using dual detection with redundancy at each level in the scheme?
To achieve higher availability
What is the main advantage of using Multi Section Digital Axle Counters (MSDACs) over conventional SSDACs?
They provide dual detection with redundancy at each level
What is the primary function of the L-I automatic reset arrangement?
To automatically reset a track section in failure state using a redundant track section
What happens when a train with low speed enters and exits the track section with equal count at the boundaries of track section?
The signal continues to be in 'ON' aspect
What is the purpose of keeping the reset track section in preparatory mode in Level-2 reset?
To ensure the track section is clear before taking off the signal
What is the condition for automatic resetting with supervisory track sections?
When a track section fails and the corresponding supervisory track section is clear
What is the primary purpose of the DN-SPT supervisory track section?
To cover all the track sections of IB in DOWN direction
What is the primary purpose of the Level-3 reset arrangement?
To manually reset all failed track sections
What happens when a track section fails and the corresponding supervisory track section is clear?
The track section is automatically reset
What is the condition for manual resetting with Level-3 reset?
When all automatic reset attempts have failed
What is the primary purpose of the reset box at a train sending station along with its corresponding Line verification (LV) box at another station?
To manually reset all track sections between both stations in a particular direction of movement
What is the voltage range that MSDAC works on?
19-72 V DC
What is the purpose of the 12x1.5 Sq.mm signaling cable used in IB Signals?
To feed the IB Signals at IB location directly from the Relay Hut
What is the purpose of the 6 quad cable used in MSDAC?
To connect the MSDAC evaluator to each DP
What is the condition for manually resetting all track sections between both stations in a particular direction of movement?
When the Station Masters of both stations have ascertained that all track sections between the stations are clear of trains in that particular direction
What is the purpose of the aspect repeating relays at signal locations?
To repeat the signal aspect at the signal location
What is the purpose of the Mini IPS in the IB location?
To derive the necessary power supplies for MSDAC
What is the purpose of duplicating the media between the Station to IB location?
To provide a backup in case of cable failure
Study Notes
Audible Indicators
- Audible indicators are used to warn the receiving station when the train has passed the Home Signal, and to warn the sending station when the train has passed the Last Stop Signal.
Non-Co-operative Type Instruments
- These instruments have an automatic "Train On Line" feature that sets the instruments to "Train On Line" position when a train enters the block section and remains in that position until the train passes the Home Signal at the receiving station.
- They also have an audible indicator to warn the receiving station when the train enters the block section at the sending station.
- Two shunting keys, one for each line, are provided, suitably interlocked with the block instruments for use as an authority for shunting in the block section.
Train Detection for Proving Block Section to be Clear
- Track circuits or Axle Counters are used to detect the presence of trains in the block section.
- An indicator is provided in each block station to show whether the block section is occupied or not.
Protective Measures against Power Line Parallelism
- Lightning Dischargers are installed separately and are the demarcating point for test purposes.
- Induced voltage due to power line parallelism should not exceed 150 V, and short circuit fault current should not exceed 430 V.
- Block filters are used in block instruments using PR relay where induced voltage exceeds 10 V.
- Block filters are used with Handle type Block instruments using frequency-coded signals.
Earthing
- A separate earth is provided for each instrument, buried at a depth of at least 1.5 meters and at a distance of at least 2.5 meters from any other earth.
- The resistance of the earth should not be more than 10 ohms.
IBS in Double Line and Single Line
- IBS is interlocked with any approved means of block working for Double Line and Single Line.
- IBS is not taken off unless line clear has been obtained from the Block Station in advance, and direction of traffic is established in Single Line.
- IB Signal is located in such a way as to split the block section into near halves, subject to other criteria.
General Note
- IB Signal is not provided in a block section with steep falling gradients, unless brake power is adequate to enable trains to be stopped at IB signal.
Annexure: 18-A1 Painting Scheme – Block Signalling Equipment
- Different colors are specified for various components of Block Signalling Equipment, such as body, operating handle, bell, and station master's control lock.
Block Instruments: Maintenance and Working
- The Last Stop Signal is automatically replaced to 'ON' when the train enters the block section and remains in the 'ON' position until the train arrives at the receiving station and a fresh “Line Clear” is obtained.
Register of Block Instruments
- The Senior Section Engineer (Signal) maintains a register containing the type of instrument, its serial number, location, and name of manufacturer, date of installation, and date of last overhaul.
- The register also contains particulars of all tokens working in each block section, those removed or lost irrecoverably, and those introduced as replacement.
Census of Tokens
- Each Sectional JE/SSE (Signal) takes a census of the tokens working in various block sections at least once in six months and keeps a record in the register of Block Instruments.
- The census information is also recorded in the Signal History Book at every station.
Damaged Tokens
- Tokens that are cracked, deformed, or worn to a smaller size than normal, or are damaged in any way, are removed, broken up, and returned to Stores.
- Advice of removed tokens is given to all concerned, and replaced with another token of the same number.
Lost Tokens
- When a token is lost and cannot be found, a joint certificate is given to the Senior Divisional/ Divisional Signal and Telecommunication Engineer and the Operating Department.
- A joint circular is issued with full particulars, cancelling the lost token for the information of the staff.
- Particulars of lost tokens are published in the Railway's Gazette and exhibited near the relevant instrument for the information of the Operating Staff.
Balancing of Tokens
- Technicians transfer tokens from one instrument to another to balance the tokens.
- Each Technician is provided with a "Token Balance Book" to record the transfer of tokens.
Intermediate Block Signalling
- The scheme consists of two major components: axle counters for track vacancy detection and exchange of signalling information between IB and stations.
- The scheme uses dual detection with redundancy at each level, including communication media, to achieve higher availability.
Description of the Scheme
- The scheme uses Multi Section Digital Axle Counters (MSDACs) for track vacancy detection and exchange of signalling information.
- MSDACs are provided with dual detection in distributed architecture.
Reset Features of MSDAC
- There are three levels of reset: automatic reset with redundant track section, automatic reset with supervisory track section, and manual reset with line verification.
Power Supply Arrangement
- The IB location is provided with a Mini IPS, which supplies 230 V AC from UP AT and DN AT.
- The necessary power supplies for MSDAC are derived from the Mini IPS, with a 24 V DC supply from the Mini IPS.
Cable Requirement
- Signaling Cable: Home & Advance starter signals are directly fed from the EI/Relay room with standard signaling cable.
- Quad Cable: MSDAC evaluator to each DP requires 1 quad of 4 conductors, with a separate 6 quad cable used for each DP of dual detection.
This quiz covers the basics of railway signaling systems, including audible indicators and block instruments. Topics include cooperative and non-cooperative type instruments and their requirements.
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