communication-based train control (cbtc)

COMMUNICATION BASED TRAIN CONTROL

PRESENTED BY,VIPIN V

vipinquilon@gmail.com 1

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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