Railway Signalling Concepts https://www.railwaysignallingconcepts.in Railway Signalling Concepts Sun, 12 Jul 2020 16:45:16 +0000 en hourly 1 https://wordpress.org/?v=5.4.2 Railways Signalling Cables | Indoor cables | Outdoor cables | Power cables https://www.railwaysignallingconcepts.in/railways-signalling-cables-indoor-cables-outdoor-cables-power-cables/ https://www.railwaysignallingconcepts.in/railways-signalling-cables-indoor-cables-outdoor-cables-power-cables/#comments Sun, 12 Jul 2020 21:54:17 +0000 http://www.railwaysignallingconcepts.in/?p=111 Railways Signalling Cables Indoor cables Outdoor cables Power cables What Is Cables ?  Cable is a unit which contains more than one insulated conductor bunched in to a compact form by providing mechanical protection and electrical insulation. PVC insulated, PVC sheathed and armoured signalling cables are used for carrying signalling circuits. Conductors are of copper […]

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Railways Signalling Cables Indoor cables Outdoor cables Power cables

What Is Cables
Cable is a unit which contains more than one insulated conductor bunched in to a compact form by providing mechanical protection and electrical insulation. PVC insulated, PVC sheathed and armoured signalling cables are used for carrying signalling circuits. Conductors are of copper and of approved size. Cables are classified as „INDOOR‟ cables and „OUTDOOR‟ cables.

What is the use Indoor cables:
Used for internal wiring of signalling circuits with copper conductor, PVC insulated without armour. Indoor cables are normally in size 60 core, 40 core, 24 core, 20 core with conductor size 0.6 mm dia. or 60 core , 40 core , 24 core & 16 core of 1.0 mm conductor dia. size.

Outdoor cable:
These are classified as Main cable, Tail cable, Power cable and Quad cable as per circuit connection requirement. Main and Tail cables are available in 4 core , 6 core , 8 core , 12 core , 20 core , 24 core and 30 core, with conductor size 1.5 sq. mm area. 1.5 sq mm (Copper conductor) 2 core size cable are used for track circuits (Feed end & Relay end) Numbering is generally started from outer most layer i.e., Starting from Blue and ends with Yellow.

Power cable:
Used as BUS BAR for power supply from relay room to location boxes. Sizes are 10 sq mm Aluminum single strand 2 core cable. 25 sq mm Aluminum single strand / multi- strand 2 core.

Quad cable:
Used for Axle counter circuits, Block line circuits. There are of 6 or 4 quad cable (1 quad = 4 conductors arranged in 2 pairs)

Testing of signalling cables:
Periodicity of Main cable Once in year, Tail cable Once in six months, Life of signalling cable 30 years, 500 volts DC Megger to be used for testing of cable. The insulation resistance should not be less than 5 Meg ohms / Km in dry weather. (For 500 Mts. 10 Meg ohms, 250 Mts. 20 Meg ohms)

Electrical Key Transmitter
Electrical key transmitter is used for the purpose of controlling a signal apparatus such as points, LC gates & signals etc by SM by retaining key of the controlled apparatus (which is normally locked) and issuing the same key for releasing the apparatus when required.

Under this system, the working of fixed equipment is locked by means of mechanical key which is electrically locked in the EKT. For extracting the key from the EKT, a pair of EKTS is required to be connected in series, one at the function end and other at controlling end and requires physical co-operation from both end operators.

The EKT keys are so designed that they enter only the instrument meant for the specific key and can not enter any other instrument of its kind. The EKTs keys are provided with provision of sealing.

Keys out : All contacts open
Key in & pressed to right side : Contacts 5 & 4; 3 & 1 make
Key in : Contacts 5 & 4; 3& 2 make

Electrical parameters:
Resistance of coil – 12.5 ohms to 15 ohms
Rated voltage – 12 V DC
Working current 150 mA to 200 Ma
Minimum Voltage 6V DC

Railways Signalling Cables Indoor cables Outdoor cables Power cables Visit Here :- http://rdso.indianrailways.gov.in 

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Railway Signalling Electrical Point Machine https://www.railwaysignallingconcepts.in/railway-signalling-electrical-point-machine/ https://www.railwaysignallingconcepts.in/railway-signalling-electrical-point-machine/#comments Sun, 12 Jul 2020 21:30:48 +0000 http://www.railwaysignallingconcepts.in/?p=162 Railway Signalling Electrical Point Machine Railway Signalling Electrical Point Machine :– An electrical point machine is an electrically driven motor used for operation of points in railway yards. The rotary motion of the motor is transmitted through the reduction gears and transmission assembly and converted through linear movement of a toothed rack through a pinion. […]

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Railway Signalling Electrical Point Machine

Railway Signalling Electrical Point Machine :An electrical point machine is an electrically driven motor used for operation of points in railway yards. The rotary motion of the motor is transmitted through the reduction gears and transmission assembly and converted through linear movement of a toothed rack through a pinion. The gear rack drives switch rails to unlock, change the position from N to R or R to N and lock the switch at the end of the stroke.

Sequence of point machine operation.

1. Opening of the detection contacts.
2. Unlock the points.

3. Move the points to the desired position
4. Lock the points.
5. Close the detection contacts.

Railway Signalling Electrical Point Machine 1

Depending up on the operating voltages
1. Low voltage .DC supplies – 24 volt DC.
2. High voltage DC supplies -110V DC.
3. High voltage AC – 380 AC.

The point machines have split series field windings.

 

Electrical parameters of point machine

1. Rated voltage – 110V DC.
2. Working current – 4-6 Amps.
3. Obstruction (slipping current) – 6-7 Amps.

4. Operating Time – 3 sec.
5. Type of machine – Combined type. (Operation, locking and detection)
6. Field winding – Split field

7. Field connection – Series
8. Movement of locking – Rotary type
9. Friction clutch – Self adjustable

Railway Signalling Electrical Point Machine 2

Main parts of point machine
1. DC series split field motor within built in reduction gear unit
2. Transmission assembly
3. Throw rod, lock slides and detection slides

4. Detection and control contact switch assembly
5. Hand crank.
6. Spring loaded friction clutch.

 

Need for remote control of point machine:
1. To avoid voltage drop in cable cross section.
2. Contact of lever /knob/push button do not have the heavy duty current carrying capacity.

3. Track locking is to be provided to prevent point operation under wheels.
4. Point machine should be protected from over load.
5. Facility for sequential operation should be provided.

 

Two types of relay control units are standardized.
1. Siemens point contactor unit.
2. Point contactor unit with QBCA relays.

 

Visit here for more information :–  https://en.wikipedia.org/wiki/Point_machine

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Railway Migration Thales https://www.railwaysignallingconcepts.in/railway-migration-thales/ https://www.railwaysignallingconcepts.in/railway-migration-thales/#respond Sun, 12 Jul 2020 21:23:57 +0000 http://www.railwaysignallingconcepts.in/?p=1126 Railway Migration Thales * Migration is the staged process of changing from existing signalling system to the new TBTC system for the Jubilee and Northern Lines. * As each phase of migration is introduced, a new boundary with the existing system is created and the boundary from the previous phase is removed. * Trains retain […]

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Railway Migration Thales

* Migration is the staged process of changing from existing signalling system to the new TBTC system for the Jubilee and Northern Lines.

* As each phase of migration is introduced, a new boundary with the existing system is created and the boundary from the previous phase is removed.

* Trains retain their existing protection system (TCP mode) during the migration phases, so that they can continue to operate in LU territory.

* Migration Phases – JL
* J2.0 – STR to CAT
* J3.0 – CAT to WES

* J4.0 – WES to DOH
* J5.0 – DOH to STA

MIGRATION BOUNDARIES – JL

 

MIGRATION BOUNDARIES - JL

MIGRATION BOUNDARIES

MIGRATION BOUNDARIES

Existing System 

MIGRATION

 

Passive Installation Data

Passive Installation Data

 

Passive Installation Data 1

 

Passive Installation – Control

 

Passive Installation - Control

 

Passive Installation – Control 1

Passive Installation - Control 1

Commission Change Over Cubicle

Commission Change Over Cubicle

Night / Weekend Testing of TBTC 

Night Weekend Testing of TBTC 

 

TBTC Commissioned 

TBTC Commissioned 

 

TBTC Commissioned 1

TBTC Commissioned 1

Change over cubicle (COC)

* COC are required to facilitate the migration of the SelTracsystem on to the Jubilee and Northern line.

* The purpose of the COC is to facilitate testing and commissioning activities during the migration phase of the JNUP by rapidly switching between the two signalling systems in a safe manner.

* COC will be implemented throughout the JL to migrate all existing wayside equipment like Points control & Detection, Trainstop Control & Detection,PDIU, RGI, COLR’s, Floodgates etc.. that will be controlled via the new TBTC system.

Change over cubicle (COC)

Change over cubicle (COC) 1

Change over cubicle (COC) 1

 

Change over cubicle (COC) 2

Change over cubicle COC 1

Change over cubicle (COC) 3

Change over cubicle (COC)3

Remote COC SER/IMR Indications

Remote COC SER IMR Indications

 

Schematic COC Arrangements

Schematic COC Arrangements

 

Cut in Design

Cut in Design

Cut in Design 1  

Cut in Design 1

 

Cut in Design 2

Cut in Design 3

 

 

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Metro Safety Concept & Practices in Signalling Dubai https://www.railwaysignallingconcepts.in/metro-safety-concept-practices-in-signalling-dubai/ https://www.railwaysignallingconcepts.in/metro-safety-concept-practices-in-signalling-dubai/#respond Sun, 12 Jul 2020 21:10:41 +0000 http://www.railwaysignallingconcepts.in/?p=2553 Metro Safety Concept & Practices in Signalling Dubai Signalling and Safety Systems   Signalling Overview   What is Fail Safety? 1. Failures- whether Equipment or Human 2. can be minimized 3. but can not be eliminated 4. Therefore, steps are required to be taken to ensure that there is no unsafe effect of failure 5. Signalling […]

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Metro Safety Concept & Practices in Signalling Dubai

Signalling and Safety Systems

Signalling and Safety Systems

 

Signalling Overview

Signalling Overview

 

What is Fail Safety?

1. Failures- whether Equipment or Human
2. can be minimized

3. but can not be eliminated
4. Therefore, steps are required to be taken to ensure that there is no unsafe effect of failure

5. Signalling Systems are designed in such a way that every Failure has a safe Reaction
This is called Fail – Safe Principle

Fail – Safe Principle

1. Fundamental principle of design of Signalling system is:
2. safe state corresponds to the lowest energy level

3. to keep the system in a permissive state, constant energy/effort should be applied
4. This ensures that due to any inadvertent situation or failure,the system comes back to the state of lowest energy—ie. Safe Sate

 

Normal system

 

Fail – safety
1. Fail – safe Principle is adopted in the design of all signalling systems- mechanical, relay based as well as software based systems
2. Example- Semaphore Signal

3. Mechaniical design is such that”stop” aspect is the stable state
4. Constant Force required to keep required to keep the signaling “ proceed” aspect.

5. Signal returns to “stop” aspect in case of breakage of transmission wire or any other failure.

 

Fail – Safety-Examples

1. Signalling Relays:
2. Stable state- Dropped (Maintained by gravity/spring action)- safe state

3. Red signal aspect controlled by Relay-” dropped”- which is lowest energy state.
4. permissive aspect controlled by Relay –”picked up”

5. Constant current required to maintain the relay in “picked Up”

 

Software Based Systems

1. Software based Signalling systems require repeated positive action to be taken to be taken by- both,software as well as hardware to keep it in permissive state.

2. Disruption of this positive action due to any failure results into reversion of the system to safe state.

 

Microprocessor and other component

 Disadvantage                               Advantage
 Are not fail safe                           Speed
 Don’t have well                           ability to perform
complex task
defined failure modes
 Are not reliable enough            Miniature size
to meet 10 -9 unsafe
failures/our. They are                   Low price
approx. 10 -5 to 10 -6

Then How is Safety Achieved?

1. Employ more resources than required (redundancy)(both hardware & software)
2. Self check procedures to detect a fault within given time period dt such that prb. of occurance of a fault within dt is < 10 -9
3. watchdog timers

 

What is Redundancy?

1. Redundancy:
2. Is the use of additional resources(whether hardware or software) than required for the normal functioning of the system

3. The additional resources should be configured judiciously to obtain max. advantage in terms of safety and reliability
4. The amount and type of additional resources and its configuration will depend on the safety and reliability requirements.

 Redundancy

Types of redundancy

1. Dual hardware redundancy
2. Dual hardware redundancy with 100% standby

3. Triple modular redundancy(TMR)
4. Software redundancy-single hardware

 

Dual hardware Redundancy (2 oo2)

Dual hardware Redundancy

 

Dual HW red+100% standby (2-2oo2)

Dual HW red

 

Triple Modular Red.(TMR) (2oo3)

Asmpn: 2 units will not fail simultaneously

Triple Modular Red

 

Software redundancy- single hardware

Assmpn: independent Softwares will react differently for a HW fault

Software redundancy

 

Self Check & Watchdog timers

1. Periodical check of microprocessor, buses,memory, peripheral especially input circuits
2. Watchdog timers-within specified time window if command is not received then system goes to safe state.

Essentials of Interlocking (as per indian railway SEM)

1. It shall not be possible to take ‘OFF’ a running signal, unless all points including isolation are correctly set, all facing points are locked and all interlocked level crossing are closed and locked against public road for the line on which the train will travel including overlap.

2. After the signal has been taken ‘OFF’ it shall not be possible to move any points or lock on the route, including overlap and isolation,nor to release any interlocked gates until the signal is replaced the ‘ON’ position.

3. It shall not be Possible to take ‘OFF’ at the same time, any two fixed signals which can lead to any conflicting movements.
4. Where feasible, points shall be so interlocked as to avoid any conflicting movement.

 

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Railway Signalling Control Tables Presentation https://www.railwaysignallingconcepts.in/railway-signalling-control-tables-presentation/ https://www.railwaysignallingconcepts.in/railway-signalling-control-tables-presentation/#respond Sun, 12 Jul 2020 21:04:53 +0000 http://www.railwaysignallingconcepts.in/?p=275 Railway Signalling Control Tables Presentation Control Tables are to be printed in A3 or A4 size. Criteria for the text size is readability and so A4 size is ok under favorable working conditions but A3 under poor working conditions. On A4 size prints, a minimum text size of  2mm is considered acceptable.   Conventions Dollar […]

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Railway Signalling Control Tables Presentation

Control Tables are to be printed in A3 or A4 size.

Criteria for the text size is readability and so A4 size is ok under favorable working conditions but A3 under poor working conditions. On A4 size prints, a minimum text size of  2mm is considered acceptable.

 

Conventions

Dollar $ References

They are a set of standard notes, to identify some of the commonly used phrases.

$ signs shown in the Code of practice only to be used in control tables.

Every set of control table should have a preface of  the list of these references .

RT/E/C/11202 A.7 gives the complete list of  $ references. The current Issue3 provides up to $101.

 

Some of the examples are :

$3    – Provision for replacement from Signal box

$14  –  Red lamp alight or controls off

$27  –  To be set and locked by individual point switch

$33  – Not detected

$35  – Continued on next sheet

$58  – TPWS failure indicated using a TPWS Failure Indication Unit

$101 – Control not effective if track circuit occupied by train proceeding away from crossing.

 

# references 

They are similar to $ references but these are specific to particular tables or set of tables.

Explanation of # reference is to be placed closer to the reference and placed on the table itself as far as possible.

 

Charecters

“*”  Asterisks  are not to be used with tables shown in this Code of Practice.

“( )” Parentheses , used for enclosing a statement  which forms a condition where this is more complicated than a single requirement. E.g.(AB or 718R)

“[ ]” Brackets are to be used in similar way as that of parentheses, for grouping some conditions at the discretion of the user.

{ } “Braces” used for enclosing longer strings of connected segments,

e.g.{RT, RS, or [34 on after (34 on, RT occ RV occ)]}

– – – “Dashes” used to connect related conditions which  extends to more than one box or column, e.g [728- – – – – or- – – – – – 728], where each occurrence of 728 will appear in a different box or column. However, enclosing bracket, braces or parentheses are essential.

“ > “ Greater than sign is used in conjunction with tables this Code of Practice.  “  “ “  “  Quotes Alpha numeric route indicators, when defined  are shown in quotes e.g. ‘M’,  ‘18’ or ‘X’ “+ “ Plus To be used when two aspects (or indications ) alight together, e.g. Y+G The aspects before and after-the plus denote the left and right hand aspects respectively. “Comma” used to separate controls where their relationship is  “and” e.g .”AA and AB”.

Abbreviations            

 “or” used to separate controls where their relationship is “one or other or both”“N” AND “R” These are suffixed point indications to indicate their position where this is not stated in the column or box heading, e.g. 718R, 765N.

“NOR” Where it is to indicate that a route and its route locking and approach locking are normal, this abbreviation follows the route numbers.  E.g. 315A (M) Nor.“Occ” To indicate track occupied conditions  e.g. “AB occ” “set” used to indicate a route is set. E.g. [ 1B (M) after 9A (M) set].

“POS” indicates the position of the junction indicator (1 to 6). E.g. POS 4.“w”  indicates that something is to happen WHEN another condition (shown after the “w”) is true. “ON’ AND “OFF” ON means the signal is displaying its most restrictive aspect and OFF means a less restrictive aspect is displayed.

Title Blocks

Title Blocks of control tables shall include the name of the controlling signal box, or control center and the interlocking identification, where appropriate.

General Notes on Control Tables           

The Control table volume should include  Notes which define rules used for the production of control tables, besides those within Standards. These Notes should find a place  immediately after the list of references.

e.g Approach Lock Release Irregular release due to power failure to be inhibited in all cases.

TORR

All Routes provided with TORR are cancelled by the passage of  the train unless required to work automatically. Facilities for manual cancellation are provided.

 

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LIMITATIONS OF 3 ASP. SIGNALLING | 4 ASP. SIGNALLING HEADWAY https://www.railwaysignallingconcepts.in/limitations-of-3-asp-signalling-4-asp-signalling-headway/ https://www.railwaysignallingconcepts.in/limitations-of-3-asp-signalling-4-asp-signalling-headway/#respond Sun, 12 Jul 2020 21:00:49 +0000 http://www.railwaysignallingconcepts.in/?p=332 LIMITATIONS OF 3 ASP. SIGNALLING * IF S ≤ DGR/2 ≤ 1.5S (OR 2S ≤ DGR ≤ 3S), THE USABLE RANGE IS LIMITED BY: ‘DGR/2’ AT ITS UPPER END & ‘S’ AT ITS LOWER END AS CAN BE SEEN BELOW. IF ‘DGR/2’ < ‘S’ (OR ‘DGR’ < ‘2S’), THERE IS NO OVERLAP OF THE BANDS AS […]

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LIMITATIONS OF 3 ASP. SIGNALLING

* IF S ≤ DGR/2 ≤ 1.5S (OR 2S ≤ DGR ≤ 3S), THE USABLE RANGE IS LIMITED BY: ‘DGR/2’ AT ITS UPPER END & ‘S’ AT ITS LOWER END AS CAN BE SEEN BELOW.

IF ‘DGR/2’ < ‘S’ (OR ‘DGR’ < ‘2S’), THERE IS NO OVERLAP OF THE BANDS AS CAN BE SEEN BELOW

 

* IT MEANS: 3ASP. SIGNALLING IS NOT ABLE TO RUN THE SERVICE.

*  SO 4 ASP. SIGNALLING SHALL BE EXAMINED IF IT CAN RUN THE REQUIRED SERVICE

4 ASP. SIGNALLING HEADWAY

* IN 4 ASP. SIGNALLING ALSO, ALL SIGNALS ARE IDENTICAL STOP SIGNALS.

* EACH SIGNAL DISPLAYS A SINGLE YELLOW ASPECT WHEN NEXT STOP SIGNAL IS AT RED.

* IT DISPLAYS DOUBLE YELLOW (FIRST CAUTION) ASPECT WHEN ITS NEXT TO THE NEXT SIGNAL IS AT RED.

 

* IT MEANS: THE SAFETY REQUIREMENT IS NOW MET BY TWO 4 ASP. SIGNAL SEPARATIONS OF ‘D4’.

* FOR SAFETY, S ≤ 2D4 ≤ 1.5S (OR 0.5S ≤ D4 ≤ 0.75S) &

* FOR SERVICE REQUIREMENTS, THE NEXT 4 ASP. SIGNAL ON APPROCH TO DOUBLE YELLOW CAN SHOW GREEN WHICH MEANS: FOR SERVICE, D4 ≤ DGR/3

 

SAFETY & SERVICE COMPATIBILITY IN 4 ASP. SIGNALLING

* IF DGR/3 > 0.75S, THE SERVICE BAND EXTENDS TO THE RIGHT OF THE SAFETY BAND AND THE ENTIRE SAFETY BAND REPRESENTS THE USABLE RANGE.

SAFETY & SERVICE COMPATIBILITY IN 4 ASP. SIGNALLING

 

 

* IF 0.5S ≤ DGR/3 ≤ 0.75S (OR 1.5S ≤ DGR ≤ 2.25S), THE USABLE RANGE IS LIMITED BY: DGR/3 AT ITS UPPER END & 0.5S AT ITS LOWER END, AS CAN BE SEEN ABOVE.

 

 

 

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Metro Rail Advantages of AFTC https://www.railwaysignallingconcepts.in/metro-rail-advantages-of-aftc/ https://www.railwaysignallingconcepts.in/metro-rail-advantages-of-aftc/#respond Sun, 12 Jul 2020 20:37:51 +0000 http://www.railwaysignallingconcepts.in/?p=2568 Metro Rail Advantages of AFTC   1. Joint less Track Circuits except in point zone. 2. Immune to AC/DC Traction interference. 3. Suitable for Non-RE Section. 4. More Length. 5. Less Depends on R B Integrity (presence) of both rails are ensured in the circuit. 6. Both Rails are available for Traction Return Current. 7. […]

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Metro Rail Advantages of AFTC

Types of A F T C

 

1. Joint less Track Circuits except in point zone.
2. Immune to AC/DC Traction interference.
3. Suitable for Non-RE Section.

4. More Length.
5. Less Depends on R B Integrity (presence) of both rails are ensured in the circuit.
6. Both Rails are available for Traction Return Current.

7. Less maintenance ,less staff more reliable.
8. Sensitive TR with high % of release are not required .

Metro Rail Advantages of AFTC TI-21 A.F.T.C.

TI-21 Can be arranged
1. End Feed arrangement(Continuous)
2. Center Feed Arrangement (Continuous) C
3. A.F.T.C. Ending with other type Track Circuit.
4. A.F.T.C. Ending with Non-Track Circuited

 

TECHNICAL SPECIFICATION OF

TECHNICAL SPECIFICATION

 

COPONENTS FOR END FEED A.F.T.C.

1. POWER SUPPLY UNIT (PSU) 2 Nos.
2. TRANSMITTER UNITS (Tx ) 1 Nos.
3. RECEIVER UNITS ( Rx ) 1 Nos.
4. TUNING UNITS (T U-Tx & TU- Rx ) 2 Nos.
5. LINE RELAY (QN1) (50 V,1350 Ω ) 1 Nos.
6. CABLES 1) Tx ,Rx TO T.U. 2 Set.
2) T.U. TO TRACK 2 Set.

BLOCK DIGRAM OF TI-21 END FEED AFTC

BLOCK DIGRAM OF TI-21 END FEED AFTC.

 

BLOCK DIGRAM OF TI-21 CENTER FEED AFTC

BLOCK DIGRAM OF TI-21 CENTER FEED AFTC 2

 

AFTC END FEED WITH NO TRACK CIRCUIT ZONE

AFTC END FEED WITH NO TRACK CIRCUIT ZONE

 

Transmitter ABB

Transmitter ABB

 

RECEIVER- ABB

RECEIVER- ABB

 

Gain Setting In T1 Type AFTC

Gain Setting In T1 Type AFTC

 

Seimen’s A.F.T.C.

• 6 System Characteristics and Technical Data
• Range of applications Station and open- line tracks, points and crossings
• Joints Electrical separation joints with S. terminal and shunt bonds
• Traction current return Two-rail

• Interference Frequency-modulated transmission provides immunity to interference
• Cable faults Protection by coded transmission and intercore short-circuit supervision
• Component failures Safety measures dual-channel design of receive equipment parallel movement (synchronism) of trac circuit relays: error detection by divergent condition of the two relays
• Shock-hazard voltages Electrical isolation between outdoor and indoor equipment

• Rated operating frequencies
• FTG S 46: 4.75 kHz, 5.25 kHz, 5.75 kHz, 6.25 kHz FTG S 917: 9.5 kHz, 10.5 kHz, 11.5 kHz, 12.5 kHz, 13.5 kHz, 14.5 kHz, 15.5 kHz, 16.5 kHz
• Modulation Frequency modulation (shift keying)
• Bit pattern for coding 15 different bit patterns
• Transmission speed For the transmission of time-multiplex bit patterns: VD = max. 200 bit/s
• Operating reliability MTBF: 5 years
• Pick-up delay of track circuitt : approx. 0.6 s (in special cases 1.3 s)
• relays
• Drop-out delay of track circuit tdr: approx. 0.25 s (in special cases 0.17 s)
• relays
• Power supply Operating voltage:
• U = 230 V AC +10 %/—15 %, 50Hz + 2%

• System Description
• VT 1 P 64
• Siemens code no:
• 43
• FTG S Track Circuit
• A25000-X22-Q41-O1-7629
• of
• without Data Transmission
• (EZS)
• 15-12-97
• Notice no: K75/D62/V

 

FTGS STANDRAD CONFG

 

BLOCK DIGRAM SEIMEN’S AFTC

BLOCK DIGRAM SEIMEN’S AFTC

 

Seimen’s A.F.T.C

Maximum Effective Length Of Track Circuit.

Seimen’s A.F.T.C

 

TRACK VACANCY DETECTION

TRACK VACANCY DETECTION

 

Modulation And Coding

Modulation And Coding

 

AFTC EQUIPMENT

AFTC EQUIPMENT

 

SEPARATION JOINTS

SEPARATION JOINTS

 

TRACK CONNECTIONS

TRACK CONNECTIONS

 

TRACK CONNECTIONS

 

Track side Connection box

Track side Connection box

 

Tx T.U.

Tx TU

Rx T.U.

Rx TU

Modulation Frame FTGS917

Modulation Frame FTGS917

Modulation Frame FOR POINT T.C.

Modulation Frame FOR POINT TC

 

Modulation Frame FOR X- ING T.C.

Modulation Frame FOR X- ING TC

Modulation Frame FTG S 46 T.C.

Modulation Frame FTG S 46 T.C.

 

Modulation Frame FTG S 46 – M T.C.

Modulation Frame FTG S 46 - M TC

Transmitter Board

Transmitter Board

Filter & Amplifier Board

Filter & Amplifier Board

 

Receiver – I Board

Receiver - I Board

 

Demodulator Board

Demodulator Board

 

Receiver – II Board

Receiver – II Board

 

Visit Here :- https://www.irfca.org/faq/faq-signal4.html

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Railway Point Control Circuit & Point Indication Circuit https://www.railwaysignallingconcepts.in/railway-point-control-circuit-point-indication-circuit/ https://www.railwaysignallingconcepts.in/railway-point-control-circuit-point-indication-circuit/#respond Sun, 12 Jul 2020 20:12:35 +0000 http://www.railwaysignallingconcepts.in/?p=1438 Railway Point Control Circuit & Point Indication Circuit Railway Point Control Circuit & Point Indication Circuit :- Fig 3.2 shows the point control circuit for an ‘N’ style frame. The differences here are the RC and NC lever bands which are used for the energisation of the respective Reverse and Normal point auxiliary valves. Note that these lever bands […]

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Railway Point Control Circuit & Point Indication Circuit

Railway Point Control Circuit & Point Indication Circuit :- Fig 3.2 shows the point control circuit for an ‘N’ style frame. The differences here are the RC and NC lever bands which are used for the energisation of the respective Reverse and Normal point auxiliary valves. Note that these lever bands are to the osimilar nes for the WL energisation. Therefore when the lever is placed either Normal or Reverse the point control circuit and the WL circuits are energised at the same time.

To prevent a race between the two circuits the WL is fed from the electro pneumatic valve via a 1/4″ (6.35 mm) bore air hose. This small bore ensures that the WL will retract from its port much quicker and before the point motor has started to move the point escapement and therefore catch on the WL.

 

 The Point Control Circuit

 

The Point Indication Circuit

Fig 3.3 shows the point indication circuit found on ‘N’ style frames. It looks identical to the ‘V’ style circuit. The difference here is that the indication lamps are fed from 100V AC and are located immediately behind the relevant point lever on the frame, labelled N and R.

 

The Point Indication Circuit.

‘N’ Style Four Foot Point Circuits.

‘N’ style circuits are similar in principle to those associated with ‘V’ style frames.

Visit :- https://cse.iitkgp.ac.in/ 

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Metro Rail Basic Components of Telecommunication Department https://www.railwaysignallingconcepts.in/metro-rail-basic-components-of-telecommunication-department/ https://www.railwaysignallingconcepts.in/metro-rail-basic-components-of-telecommunication-department/#respond Sun, 12 Jul 2020 20:03:15 +0000 http://www.railwaysignallingconcepts.in/?p=2610 Metro Rail Basic Components of Telecommunication Department The basic components of telecommunication department can be stated as follows: 1. FOTS ( Fiber Optic Transmission System) 2. PIDS (Public Information Display System) 3. PAS (Public Address System) 4. Master Clock 5. CCTV (Closed Circuit Television) 6. Radio System 7. EPABX (Electronic Private Automatic Branch Exchange) Operational […]

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Metro Rail Basic Components of Telecommunication Department

The basic components of telecommunication department can be stated as follows:

1. FOTS ( Fiber Optic Transmission System)
2. PIDS (Public Information Display System)
3. PAS (Public Address System)

4. Master Clock
5. CCTV (Closed Circuit Television)
6. Radio System
7. EPABX (Electronic Private Automatic Branch Exchange)

Operational Control Center (OCC)

1. Located at Shastri Park and Barakhamba.
2. It controls both Rail & Metro Corridor.
3. Here all the central systems of various systems are located.
4. All the train movements are supervised and system monitoring equipments are installed in OCC.

OCC Theatre

OCC Theatre

CHIEF CONTROLLER AT  OCC – VIEW OF OCC FROM TOP

 

CHIEF CONTROLLER AT OCC VIEW OF OCC FROM TOP

 

EQUIPMENT ROOM IN OCC

EQUIPMENT ROOM IN OCC

 

FOTS 

FOTS

SDH RING DIAGRAM 

 

SDH RIND DIAGRAM

 

Public Information Display System (PIDS):

It is used to display traffic & train scheduling information also data related to arrival & departure time and other information along the station and various platform areas .

Public Information Display System

 

Public address system(PAS):

1. It is used to broadcast voice messages to passengers/staff in all stations , depots ,OCC and DMRC Headquarter.
2. Also used for emergency evacuation broadcast .

Master Clock system:

Clock system is used to provide accurate time to staff, passengers and time reference to systems at DMRC. Accurate and synchronized time information is obtained from Global Positioning System (GPS) by Master Clock at OCC.

Master Clock system

 

Closed Circuit Television System(CCTV):

1. This is used to monitor the station and the platforms along with the metro corridors where it is very difficult to keep a view on the corridors.

2. Mostly it is used for security reasons and help train operators in the curved station platforms.

Electronic Private Automatic Branch Exchange (EPABX) :

For purpose of planting communication link between different stations, DMRC has its self-sustained telephone exchange. This system works on -48 V DC. Data is processed at a rate of 64k bps.

 

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Metro Rail Communication Through Radio Systems  https://www.railwaysignallingconcepts.in/metro-rail-communication-through-radio-systems/ https://www.railwaysignallingconcepts.in/metro-rail-communication-through-radio-systems/#respond Sun, 12 Jul 2020 19:51:49 +0000 http://www.railwaysignallingconcepts.in/?p=2620 Metro Rail Communication Through Radio Systems  Radio Waves A radio uses electromagnetic waves to send information across the air. This is accomplished by producing an electrical signal that moves back and forth, or oscillates, at a rapid rate.   Technology in use: 1. Terrestrial Trunked Radio (TETRA) (formerly known as Trans European Trunked Radio) is […]

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Metro Rail Communication Through Radio Systems 

Radio Waves

A radio uses electromagnetic waves to send information across the air. This is accomplished by producing an electrical signal that moves back and forth, or oscillates, at a rapid rate.

 Frequency Spectrum

 

Technology in use:

1. Terrestrial Trunked Radio (TETRA) (formerly known as Trans European Trunked Radio) is a specialist professional Mobile Radio and two-way transceiver specification.

2. This standard was developed by the ETSI for private mobile radio. Open standard for private mobile radio. It defines radio services and interfaces
3. The TETRA standard defines the air interface between mobile stations and the infrastructure.

Radio system

1. The Radio system is a digital trunked radio system, operating in 380-400 MHz band and confirming to TETRA standards.
2. The Radio system have central control equipment installed in OCC.
3. The Radio system uses EBTS towers for communication in rail corridor & leaky coaxial cable along each track in the tunnels for communication with train borne mobile radio (in metro corridor) .

RADIO CENTRAL EQUIPMENT AT OCC

RADIO CENTRAL EQUIPMENT AT OCC

 

Trunking

The trunking concept allows channels or other resources to be made available to users as they are needed. It allows all the channels to be pooled together. As a channel is needed, the controller grants an available channel from its pool of channels.

TETRA Trunking

TETRA Trunking

 

Talk group
1. In most organizations, radio users work in groups that are based on their functions and responsibilities. These groups of radio users can be assigned to communication talk groups that reflect their function or responsibilities.

Calls are semi-duplex.

TYPES OF MODES OF COMMUNICATION:

1. Trunk Mode Operation: It represents communication between two or more TETRA mobile stations with the use of trunking network infrastructure.

This mode consists of 4 communication modes:
(a) Group mode (b) Private mode
(c) Phone mode (d) Emergency mode

 

Trunk Mode Operation

(a) Group Mode:

It is a half duplex communication mode in which many users can communicate with each other by selecting a common talk group.

(b) Private Mode:
It is a half as well as full duplex communication mode in which many users can communicate with each other privately without interfering the talk group. It uses two frequencies.

(c) Phone Mode:
It is a full duplex mode of communication in which a radio user can talk to any dialed phone number within Metro or external network connected to metro.

(d) Emergency Call:
The emergency key is provided on every radio equipment, an audio visual alarm will appear on every radio unit in that talk group. The party who initiates the call has the highest priority for calling.

 

2. Direct Mode Operation:
It represents direct communication between two or more TETRA mobile stations without the use of trunking network infrastructure.

Simplex mode of communication.

Simplex mode of communication

 

EBTS (Enhanced base Transreceiver System)

• It provides RF interface from the master site to the mobile subscribers in a TETRA system. It can be categorized in two configuration:
(a) Above ground (Rail corridor)
(b) Under ground (Metro corridor)

•Both are of same configuration & characterstics.

EBTS

OCC

OCC

 

Transmitter
1. A transmitter transmit radio signal.
2. A transmitter usually has a power supply, an oscillator, a modulator, and amplifiers.

Transmitter Block Diagram

 

Receiver
1. A receiver is a device that receives a radio signal from an antenna and decodes the signal for use
2. Generally, receiver refers to a demodulator, a preamplifier, and a power amplifier

 

Receiver Block Diagram

Receiver Block Diagram

Types of radio

1. Mobile Vehicle radio\Fixed

(a) RAU (Radio Access Unit) or Zetron radio set or Station radio
(b) Train radio set
(c) RCW (Radio console workstation)

2. Mobile Portable radio

Each radio has its radio identification which register itself in central system for its function. The radio is programmed for its ID, frequency, network code, talk group and allowing types of call. Radio consists of trans and receiver and frequency synthesizer circuit which function along with DSP (Digital Signal Processor) for digital function.

RAU(Radio Access Unit)

1. It is located in the Station control room.
2. It is placed in the best radio coverage and it is fixed & has a functionality just like a telephone radio.

3. It is ideally suited to radio operator dispatchers and where office personnel need access to a radio system without wanting to have a radio placed into the office environment.
4. The M390 is a robust telephone style desktop controller with a large ,easy to read LCD display & handset.

RAU(Radio Access Unit)

Train radio

1. MTM700 Mobile radio is installed at front & rear cab for communication between the train driver & designated station controllers at OCC & Depots.
2. This radio unit is connected to different units e.g. TRIU,TRCP; these units are required to communicate with RCW ,TIMS, ATS and rear cab radio.
3. Dome type omni directional antenna is located at top roof of train. This antenna is connected through RF cable which is connected to radio unit.

Front and rear view of Train radio in cab

Front and rear view of Train radio in cab

 

Trainborne equipment

Trainborne equipment

 

Radio console workstation

• It is for different controllers that is working in OCC such that chief and traffic controllers ,etc.
• On its MMI ,all the radio information is displayed and communication can be set up only by clicking the radio identity.

Hand Portable radio

The hand portables come with 3×4 keypads, rotary switch dial, and LCD for number dialing and maximum flexibility. Each hand portable is equipped with an ultra high capacity batteries (Li ion or Li Mgh.) for longest standby and talk-time of 24 hrs, that is 5% transmit, 5% Receive and 90% standby.

Hand portable is suitable for all kinds of calls used in DMRC.

Advantages of TETRA:

1. The frequency used gives longer range, which permits high levels of geographic coverage with a smaller number of transmitters, thus cutting infrastructure costs.
2.Unlike the cellular technologies, TETRA is built to do one-to-one, one-to-many and many-to-many.

3. Rapid deployment (transportable) network solutions are available for disaster relief and temporary capacity provision.
4. In the absence of a network mobiles/portables can use ‘direct mode’ whereby they share channels directly (walkie-talkie mode).

Disadvantages of TETRA:

1. Requires a linear amplifier to meet the stringent RF specifications that allow it to exist alongside other radio services.
2. Handsets are more expensive than cellular.

3. Handsets can sometimes interfere with badly designed (usually old) or sensitive electronic devices such as broadcast (TV) receivers, hospital equipment, speed cameras.

Conclusion:

1. TETRA communication system has been implemented successfully
2. The signals are clear
3. The voice clarity is excellent
4. The TETRA technology effectively meets DMRC’s operational and functional expectations

For More Information :- https://www.ltmetro.in/hyderabad-metro-rail/project-highlights/telecom-system/

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