communication-based train control (cbtc)
DESCRIPTION
Communication-based train control (CBTC) is an automated control system for railways that ensures the safe operation of rail vehicles using RF data communication between various control entities that make up the system.TRANSCRIPT
Introduction
Train control
Train control block diagram
Existing system
CBTC block diagram
Trainborne equipments
Message formats
Communication systems
Advantages & disadvantages
Reference
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TABLE OF CONTENTS
• Communication-based train control (CBTC) is an automated control system for railways that ensures the safe operation of rail vehicles using RF data communication between various control entities that make up the system.
• CBTC is a modern successor of the traditional railway signaling systems which provide a limited control using track circuits , interlocking , and signals.
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INTRODUCTION
TRAIN CONTROL
1.Train Protection
2.Train Operation
3.Train Supervision
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1.TRAIN PROTECTION
•Train detection
•Train separation
•Route interlocking
•Overspeed protection
•Train and track surveillance
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2.TRAIN OPERATION
•Train starting
•Train speed regulation
•Train stopping
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3.TRAIN SUPERVISION
•Schedule design and implementation
•Route assignment
•Performance monitoring
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TRAIN CONTROL BLOCK DIAGRAM
Fig 1
Train supervision Train protection Train operation
Passenger demands
Operational requirements etcBraking control
Acceleration control etc
EXISTING SYSTEMS
• Automated train protection
• Manual train operation
• Maual train supervision
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SIGNALING SYSTEMS
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• Give visual display of track conditions
• Operate devices according to these signals
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BLOCK
•Fixed block : block have fixed length.
•Moving block: computers calculate block distance (CBTC), Can increase track capacity Only one train at a block
Fig 2
Low speed
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TRAIN DETECTION
1. Track circuits
2. Axle counters
In CBTC function of both are doing by trasponders called TAGS
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1.TRACK UNOCCUPIED
Fig 3
insulated
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1.TRACK OCCUPIED
Fig 4
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2.AXLE COUNTERS
Fig 5
Axile couters have many advantages over track ciruit.......
counter1
counter2
comparator
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1.WAYSIDE SIGNALLING
Fig 6
For giving visual identification of ahead track
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Modified cab signaling is Used in CBTC.
Fig 8
2.CAB SIGNALLING
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CAB SIGNALLING
Fig 9
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2.CAB SIGNALLING
Fig 7
1. Clear display of track conditions
2. Can used with CBTC
3. Can used for high speed raiway
4. Free from fog, rain, and snow
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An interlocking is an arrangement of signals and signal
appliances so interconnected that functions must succeed
each other in a predetermined sequence, thus permitting safe
train movements along a selected route without collision.
INTERLOCKING
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INTERLOCKING
Train 1 Train 2
Fig 10
•Mechanical interlocking
•Electro-mechanical interlocking
•Electronic interlocking (used in CBTC)
Interlockingdevice
CBTC PROVIDES
1.Fully automated remote Train Protection
2. Automatic Train Operation
3. Automatic Train Supervision
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CBTC BASIC FUNCTIONAL ARCHITECTURE
Fig 11
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CBTC BASIC FUNCTIONAL ARCHITECTURE
1.Mobile unit
Interrogator antenna (AI)
Antenna (A)
Trainborne equipments
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CBTC BASIC FUNCTIONAL ARCHITECTURE
2. Wayside units
RF trasmitting cables
Optical fiber cables
Inter locking and other control equipments
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CBTC BASIC FUNCTIONAL ARCHITECTURE
2. Control centers
Base data radio (BDR)
User terminal (UT)
System controller (SC)
communication controller (CC)
communication equipments (CE)
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CBTC BLOCK DIAGRAM
Fig 12
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TRAINBORNE EQUIPMENTS
On board computers (OBC)
Mobile data radio (MDR)
Control unit(CU)
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TRAINBORNE EQUIPMENTS
Fig 13
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TRAIN – TRAIN COMMUNICATION
Train 1 Train 2
Train 3
Fig 14
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WAYSIDE TO TRAIN MESSAGE FORMAT
Fig 15
N :train number
Nc :cab number
Xe :tocken number
Nr :BDR identification number
L :train length
Vob :obstacle speed
Dp :direction of motion
ES :emergency stop
N :train number
Nc :cab number
Xi :tag number
Xj :distance from tag
Lt :train length
Vt :train speed
M :mode of operation
BR :brake state32
TRAIN TO WAYSIDE MESSAGE FORMAT
Fig 17
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COMMUNICATIONS CHANNEL ARCHITETURE
Fig 18
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COMMUNICATIONS STANDARDS
Protocol using : high data link connection (HDLC)
Fig 19
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COMMUNICATIONS STANDARDS
Type of link : fullduplex type
Digital modulation Methods : BFSK
Channel access method : CDMA
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1. Increased rail capacity through closer train operation
2. Improved efficiency and flexibility ofthe rail network
3. Improved service reliability
4. Increased safety
5. Reduced operation and maintenance cost for the trackside infrastructure
ADVANTAGES
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1. Complex system
2. Intial cost high
3. Need experienced workers
DISADVANTAGES
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REFERENCES
What is communication-based train control?, Rober d pascoe and Thomas, IEEE 2009
Development of the communications-based train control system for Moscow Metro ,
Minin, V.A.; Shishliakov, V.A.; Holyoak, IEEE 2007
Towards modeling and evaluation of availability of communication based train control
(CBTC) system, Hongli Zhao, Tianhua Xu. IEEE 2009
Evolution of Communication Based Train Control worldwide , Morar s, IEEE 2010
Automatic restart for communication based train control systems, Mirtchev, IEEE 2005
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