80 Questions
What should the maintenance terminal of an Electronic Interlocking system provide for the Signal Technician?
Diagnostic tools for fault detection
What is the purpose of Block Working built into EI?
To take a line clear when the block section is clear
What is the primary principle of fail-safe circuit design?
To cause a signal to display a most restrictive aspect
What should be considered when designing fail-safe electronic equipment?
The effects of faults, component ageing, and variations in component values
What is the purpose of separating terminals in fail-safe equipment?
To eliminate the possibility of external objects causing short circuits
What is the purpose of a shroud in fail-safe equipment?
To prevent external objects from causing short circuits
What should be provided in accordance with drawing no.RDSO/S/32019?
Indication of TCF, TGT, TOL, Bell, Block clear, SNK, SNOEK
What should be a consideration in the design of circuits using electronic devices?
Due consideration to the effects of faults in fail-safe electronic equipment
What is the primary purpose of the physical 'SM Key' in the Control Terminal?
To protect against unauthorized operation of the Control Terminal
How many separate 'SM Key' relays are used in the relay room for redundancy purpose?
Two
What is the purpose of taking the relay contacts through two different input cards in different OC's?
To provide redundancy in the system
What type of counters should be provided while working with Control Panel or Control Terminal?
Non-resettable counters
What is the minimum time delay required for unblocking all signals, points, and lines after startup?
120 seconds
What is the purpose of the 'All Un Block' option provided during startup?
To unblock all signals, points, and lines after a time delay
How should the blocking of a function be indicated on the Control Terminal?
By a different mark or colour over the concerned function
What is the purpose of providing a switchover facility between Control Panel and Control Terminal?
To allow switching between Control Panel and Control Terminal or between two Control Terminals
What is the primary consideration for the size of the Control Terminal?
To display the layout of the Yard in well-proportioned dimensions
What is the purpose of the 'SM Key' in the Control Terminal?
To protect against unauthorized operation
How are the relay contacts of the 'SM Key' taken in the relay room?
Through two separate input cards in different OC's
What is the requirement for the 'Block' and 'Un-Block' feature in the Control Terminal?
It should remain effective even during changeover from one Control Terminal to another
What is the stipulation for Control Panels in future Electronic Interlocking installations?
They should not be used in future E.I installations
What is the requirement for the operation of Signals, Points, and other Controls in the Control Terminal?
They should be carried out through appropriate dropdown menus or other approved means
What is the consideration for the redundancy of the Control Terminal?
It should be provided through two separate input cards in different OC's
What is the requirement for Video Display indications on the Control Terminal?
They should conform to Control Panel indications and UFSBI Block panel as Block working built into Electronic Interlocking (EI)
What type of electronic interlocking system installation is required?
Route setting type using Dropdown menu or Entry/Exit control
What is the redundancy requirement for Electronic Interlocking systems?
Adequate built-in redundancy as per approved specification
What is the display requirement for Control Terminal?
Display of Yard layout in well-proportioned dimensions
How shall the operation of Signals, Points and other Controls be carried out?
Through appropriate dropdown menus or other approved means
What is the requirement for Control Panels in future Electronic Interlocking installations?
Control Panels shall not be used
What is the requirement for Video Display indications on Control Terminal?
Conform to Control Panel indications as covered in Para 21.1.4
What is the requirement for Control Terminal/multiple Control Terminals?
Appropriate size to display layout of the Yard in well-proportioned dimensions
What type of control shall be provided for Control Terminal/multiple Control Terminals?
Redundant mode
What is the primary purpose of the 'All Un Block' option in Electronic Interlocking system?
To unblock all signals, points, and lines after a time delay
What is required for unblocking of a function in Electronic Interlocking system?
SM's key
How should the blocking of a function be indicated on Control Terminal?
By a different mark or colour
What is the condition for operating points in Electronic Interlocking system?
When the interlocking is free and the point track circuit is clear
What is the purpose of the latch relay in point control circuits?
To make the last controlled position of points available
What is the purpose of the mid stroke point reversal preventing feature?
To prevent point operation when the point is under operation
What is the requirement for controlling each 'Normal' or 'Reverse' operation of point?
Two output relays derived from two output bits
What is the requirement for operating a point when the point zone track circuit fails?
Inserting an emergency key in a separate box
What is not required for clearing Calling On signals?
Stop signal ahead is not blank
When is approach locking or dead approach locking provided?
For all manual stop signals
What is provided on the control panel where section ahead is worked on Absolute Block System?
A white indication for block control on the last stop signal
What is the purpose of interlocking between conflicting routes?
To achieve route interlocking electric circuits at route initiation stage
What is not required for clearing shunt signals?
Stop signal ahead is not blank
What type of interlocking system installation is allowed?
Route setting type
What is the condition for operating points in Electronic Interlocking system?
Points are operated by individual operation of switches or push buttons
What is the purpose of controls on level crossings, ground frames, cabins, sidings etc.?
To suitably interlock with other controls
What is the condition for operating points in Electronic Interlocking system?
Points are correctly set and locked in the route
What is required in Signal Clearance to allow gate closing?
All interlocked level crossing gates are closed and locked against road traffic
What is the requirement for route setting and clearance of signal?
SM's key is In and interlocking is free
What is the limitation on the number of relay contacts in series?
Not more than 45
What is the requirement for new installations?
Route setting type interlocking
What is the requirement for track circuits in the route?
Track circuits are clear
What is the requirement for crank handle keys in the route?
Crank handle keys are locked and control is not released
What is the requirement for slot from other agency?
Slot is received and proved
What is the condition for emergency cancellation of a calling route without providing any back lock track?
On physical verification of the full route by SM
What is the timer delay for signal overlap (release) in big yards?
60 seconds
What is the primary condition for calling on signal below Home Signal to be initiated?
Train has come to a stop, as ensured by SM
What is the delay in seconds for opening of LC gate (Gate signal at 180 m from LC) with sequential proving of two track circuits?
0 seconds
What is the purpose of signal overlap (release) timer in relay interlocking systems?
To start automatically on clearance of last back track circuit of Home Signal route
What is the condition for calling on signal below Home Signal to be initiated in terms of train movement?
Train has passed beyond signal overlap track circuits
What is the primary purpose of providing sequential proving of two track circuits in relay interlocking systems?
To prove that train has passed beyond LC gate
What is the timer delay for signal overlap (release) in normal yards?
120 seconds
What is the primary consideration for the design of circuits of interlocking?
Industry's best practices and principles of Reliability, Availability, Maintenance, and Safety
What is the purpose of using dual OFC in Distributed type of Electronic Interlocking?
To reduce the extent of copper cables and provide an alternate path in case of failures
What is the requirement for the display of the layout on the front of the Control Panel?
It should be well-proportioned
What is the primary purpose of separating the areas covered by each track circuit on the Control Panel?
To distinguish the areas covered by each track circuit
What is the requirement for the design of circuits using electronic devices?
The design should consider industry's best practices and principles of Reliability, Availability, Maintenance, and Safety
What is the primary purpose of using a domino type panel in Control Panels?
To provide additional facilities, such as Block Working
What is the requirement for the design of circuits of interlocking in existing installations or alterations?
The design should be Non-route Setting Type, i.e., Route is set with individual operation of points
What is the primary purpose of providing a clear indication of the route setting on the Control Panel?
To enable the signal technician to operate the signals and points efficiently
What indication should be given on the control panel for a shunt signal located on the same post as a running signal?
A white light strip below the running signal indication
What should be lit up on the control panel when set for automatic working?
A white light for 'A'/'AG' marker indication
What indication should be given on the control panel for the 'OFF' aspect of a shunt signal?
A slanting white light strip
What should be indicated on the control panel when a 'Calling on' signal is 'OFF'?
A white light below the running signal indication
What should be indicated on the control panel for the 'ON' aspect of a shunt signal on an independent post?
A white light strip or two miniature white lights
What should be indicated on the control panel for the failure of green aspect?
Green flashes red, blank
What should be indicated on the control panel for the failure of double yellow aspect?
Both green and red flash
What should be indicated on the control panel for the failure of red aspect?
Green not lit, red flashing
Study Notes
Control Panel/Control Terminal
- Control Panels shall not be used in future Electronic Interlocking (E.I) installations.
- Control Terminal/multiple Control Terminals shall be of appropriate size to display the layout of the Yard in well-proportioned dimensions and shall display all functions clearly distinguishable.
- Normally Control Terminal/multiple Control Terminals shall be provided in redundant mode.
Video Display Indications
- Video Display indications on Control Terminal shall conform to Control Panel indications and UFSBI Block panel as Block working built into Electronic Interlocking (EI).
Operation and Control
- Operation of Signals, Points, and other Controls such as Gate, Crank handle, Siding, Slot, etc. shall be carried out through appropriate dropdown menus or other approved means.
- Control Terminal shall have suitable protection facility against unauthorized operation which may be provided by physical "SM Key" in a separate box.
Emergency Operations
- All Emergency operations shall be two-step process protected against unintended operations.
- Emergency operations provided when point zone track circuit fails and after line verification from site by traffic personnel.
Block Working and Controls
- Control Terminal shall have provision for Signal, Point, and Line Block Collars equivalent of Control Panel in the form of individual "Block" & "Un-Block" feature which shall remain effective even during changeover from one Control Terminal to other Control Terminal.
- Only non-resettable counters shall be provided while working with Control Panel or Control Terminal.
Maintenance and Interlocking
- Maintenance Terminal of Electronic Interlocking system shall be provided for the Signal Technician.
- Block Working built into EI shall be provided for line clear purpose.
Design Principles
- Fail-safe principles shall be incorporated in the design of the equipment.
- Component failure shall be self-detecting by way of causing a signal to display a most restrictive aspect as far as practicable.
- All fail-safe circuits shall work on continuous energisation principle such that open circuits in wiring, relay contacts, etc. or loss of power supplies shall not cause unsafe conditions.
Electronic Interlocking System
- Electronic Interlocking System shall be suitable for working on Electrified and Non-Electrified sections.
- Electronic Interlocking System Installation shall be of Route setting type using Dropdown menu Or Entry/Exit control with a facility for individual operation of points.
- Signalling and interlocking arrangements for the Yard shall be in accordance with the approved Signal Interlocking plan (SIP) and Control Table.
Interlocking Circuits
- Interlocking between conflicting routes is achieved through route interlocking electric circuits at the route initiation stage.
- Approach locking or dead approach locking is provided for all manual stop signals, effective from a predetermined point on approach of the signal.
- Controls on level crossings, ground frames, cabins, sidings, etc., are suitably interlocked.
Route Setting Type
- Route setting and clearance of signal are done with the following conditions:
- SM's key is in
- Interlocking is free
- Points are correctly set and locked in the route, including overlap and isolation (if any), to the desired position
- Crank handle keys for all motor-operated points in the route, overlap, and isolation are locked and their control is not released
- All interlocked level crossing gates are closed and locked against road traffic in the route and overlap (if any)
- Slot from other agency has been received
- Track circuits in the route up to the next signal/dead end, overlap, and isolation, and fouling (if any), are clear
Non-Route Setting Type
- For existing installations and alterations only; no new installations of non-route setting type to be provided
- Route setting and clearance of signal are done with individual operation of points and push buttons
Controls and Indications
- A white indication for block control on the last stop signal should be provided on the control panel, where:
- Section ahead is worked on Absolute Block System and control panel and block instrument are placed at different locations
- Block working is by means of axle counter or track circuit
- Control panels should have a well-proportioned display of the layout on the front, with areas covered by each track circuit clearly distinguished by different colors
- Signal indication for 'ON' aspect of a shunt signal on the same post as the running signal is not required
- Signal indication for 'OFF' aspect of a shunt signal shall be given by a slanting white light strip or two miniature slanting white lights
Timers in Various Circuits
- Timers are provided for various circuits, including:
- Calling On signal below Home signal
- Opening of LC gate
- Signal Overlap (release)
- Emergency cancellation of calling route
- Timers have specified delays in seconds for each circuit
Quiz on Control Panel and Control Terminal requirements in Electronic Interlocking Installations, including display and functionality specifications.
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