A

Seminar On

ANTI COLLISION DEVICE

Submitted In Partial Fulfillment for the Award of Degree

Of

Bachelor of Technology

In

Mechanical Engineering

2012-2013

Submitted By: - Guided By: - Submitted To:-ABHINAV BARTHWAL Mr. HAMID ALI Mr.RANJEET S. RATHOREIV B.Tech. VIII SEM HOD, EI&C DEPT. ASST. PROFESSOR

GOVERNMENT ENGINEERING COLLEGE, BIKANER

March, 2012-13

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ACKNOWLEDGEMENT

First of all I thank Mr. RANJEET SINGH RATHORE for giving me the opportunity to prepare aseminar on ANTI COLLISION DEVICES.

I would also like to thank Mr. J.P. Bhamu and all the staff of Mechanical department for theirhelp and support.

It is my pleasure to acknowledge the invaluable assistance received from Indian railways whichprovided information regarding ACDs on internet. I am also thankful to the rail journalspublished on the topic.

My sincere thanks to Patent Design and Trademark department of India for providinginformation regarding patent of ACDs. There are some newspapers and other sources fromwhere I have taken help, So, I would also like to thank them.

Thank is also due to Mr. Rajaram Bojji, Inventor of this path-breaking technology for design anddeveloping of such a system.

Last but not the least I want to thank my guide Mr. HAMID ALI for his great help andcontinuous support.

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CANDIDATE’S DECLARATION

I, ABHINAV BARTHWAL, a student of B.Tech. of Mechanical Engineering Department ofGovernment Engineering College Bikaner, hereby declare that I own full responsibility for theinformation, results, conclusions, etc provided in Seminar report titled “ANTI COLLISIONDEVICE” submitted to RTU, Kota, Rajasthan, INDIA for the award of B.Tech. (MechanicalEngineering) degree.

I have completely taken care in acknowledging the contribution of others in this academic work.I further declare that in case of any violation of intellectual property rights or copyrights found atany stage, I, as the candidate will be solely responsible for the same.

Place: BIKANER ABHINAV BARTHWAL

Date:

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CERTIFICATE

This is to certify that Seminar report entitled “ANTI COLLISION DEVICE” submitted byABHINAV BARTHWAL in partial fulfilment of the requirement for the award of the degree ofBachelor of Technology in Mechanical Engineering of RTU Kota, Rajasthan, INDIA is arecord of student’s own work carried out under our supervision and guidance.

It is understood that by this certificate the undersigned do not endorse or approve anystatement made, opinion expressed or conclusion drawn therein but approve the report only forthe purpose for which it is submitted.

Mr. HAMID ALI

(HOD)

EI&C DEPARTMENT

GEC, Bikaner

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PREFACE

This seminar report deals with the design and development of Anti Collision Devices. Thisdevice is developed by Konkan railways for the prevention of train collisions in India.

ACDs are being developed and tested for the last ten years. An advanced version i.e. ACDversion II also known as Train Collision Avoidance System has been developed which is alsoconsidered and explained in this report.

This device is a path-breaking system and one of its kind all over the globe. The installation ofthis system in railways will decrease the accidents to a considerable level. Also with fewadjustments and advancements, this system can be used on other transportation modes forsafety.

This device seems to have a vast area of application in the future from being a tracking systemall the way to unmanned transportation.

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TABLE OF CONTENTS

S.No. TOPIC Page No.

ACKNOWLEDGEMENT ii

CANDIDATE’S DECLERATION iii

CERTIFICATE iv

PREFACE v

1 INTRODUCTION 1

2 NEED OF ACDs 2

3 TECHNOLOGY USED 4

4 CONSTRUCTIONAL DETAILS 6

5 WORKING OF ACDs IN INDIAN RAILWAYS 9

6 FEATURES OF ACD 12

7 FUNCTIONS OF ACD 13

8 NON -PREVENTABLE ACCIDENTS EVEN WITH ACDs 14

9 DEFICIENCIES IN ACDs 15

10 TECHNICAL ADVANCEMENT IN ACD 16

11 FEATURES OF ACD 19

12 APPLICATIONS 19

SUMMARY 20

REFERENCES 21

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TABLE OF FIGURES

FIG.No. TITLE PAGE No.

1 TRAIN ACCIDENTS IN INDIA 03

2 WORKING OF ON – BOARD ACDs 05

3 FLOW DIAGRAM OF LOCO ACD 07

4 FLOW DIAGRAM OF STATION ACD 09

5 UNIT FOR LOCOMOTIVE 10

6 ACD NETWORK 11

7 WORKING OF TCAS 17

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ANTI COLLISION DEVICES (ACDs)

1. INTRODUCTION:

The ACD Network is a Train Collision prevention system designed, developed and patented byKonkan Railway Corporation Limited (A Public Sector Undertaking of Ministry of Railways,Government of India).Its concept was first proposed by the former chairman of Konkan railways Mr. B raja ram in the90s.Its patent was filed in the sept 1999 and the patent was granted in the year 2005.It is a self-acting microprocessor-based data communication device which when installed onlocomotives (along with an auto-braking unit - ABU), guard vans, stations and level-crossinggates (both manned and unmanned), prevents high-speed collisions in mid-sections, station areasand at level-crossing gates.The ACD uses both radio frequency and Global Positioning System (GPS) through satellites,whereby a train is automatically brought to a halt if the track ahead is not clear. The train startsbraking 3 kms ahead of a blockade.The Anti-Collision Device (ACD), also called `Raksha Kavach,' envisages setting up a networkof "self-acting" micro-processor based communication devices which automatically apply brakeson trains that are unknowingly getting into a "collision-like situation," including before stationsand at mid-sections. "At the mid-sections, where neither the protection of signals nor guidance isavailable to the driver, the ACD makes the loco intelligent and extends its capability to detectany collision-like situations in a range of 3 km, which the driver cannot detect on his own.Situations like collision between two approaching trains or between a derailed train on one trackand an approaching train on the adjacent tract can thus be prevented, according to the KRCLofficial.The "silent" network of ACD systems can be installed on the locomotives, guard vans and atstations, which could ensure that trains do not collide at while travelling at high speeds. Further,if the ACD systems are provided at the level crossing gates (both manned as well as un-manned),the project could provide protection to the lives of road users also. "We have tested thecommercial prototypes of ACD system, which has been developed indigenously for the first timein the world. It has been technically proven during joint field trials with Research Design andStandards Organization, nominated by the Railways," the official said.The ACDs are capable of multi functions. For example, while approaching a station, the LocoACD gives the "station approach" warning to the driver about 2 km in rear of the first STOPsignal of the station and in case the driver ignores the warning it will automatically regulate thetrain speed.The pilot project implementation of ACD was successfully commissioned on the North-EastFrontier Railway this year. Survey for expanding the system to another 10,000 km falling on thecritical and busy sections of the network is almost complete.

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The installation of this device will go a long way in preventing collision accidents. Theapplication of this device has been refined to not only prevent mid-section collisions but also topre-empt their occurrence in station yards.

The newly engineered solution is integrated with the signaling systems and interlocking to reactappropriately in case collision-like conditions are perceived at the time of reception and dispatchof trains from a station. The design of crash-worthy coaches and tight lock couplers with anticlimbing features has been finalized and all future coaches are being made as per the new design.

2. NEED OF ACDs

Indian railways are the world's second-largest railway, with 6,853 stations, 63,028 kilometres oftrack, 37,840 passenger coaches and 222,147 freight cars. Annually it carries some 4.83 billionpassengers and 492 million tons of freight. Of the 11 million passengers who climb aboard oneof 8,520 trains each day, about 550,000 have reserved accommodations. Railways is an Eco-Friendly and Popular mode of Transport in almost all cities of the INDIA. It provides vitalconnectivity between major commercial system at low cost. It is also the most used method oflong distance transportation in India. But with the increase in number of passengers and trafficduring the last 10-15 years the frequency of train accidents has also increased rapidly.Out of total accidents around the world approximately 15% occur in India. These accidents takehundreds of lives, disable many people and causes high financial losses to the Indian Railways.The number of accidents in the recent years are as follows

YEAR No. Of Accidents2007-08 1932008-09 1772009-10 1652010-11 1392011-12 131

As the number of passengers is increasing day by day, the rail routes are getting busier. Thisincrease in the traffic also increases the chances of accidents. In Mumbai during the peak hourstrains reach at stations with an average time interval of 3-5 min. With this much close intervalbetween the arrival of trains there are high chances of collisions between the trains. As thesetrains carry 6.94 million passengers per day, even small accidents will have catastrophic effecton the people of Mumbai. Although an Auxiliary Warning System (AWS), has been operationalin Mumbai’s Central and Western Railways for the past 15 years and there have been very fewmajor accidents. But a more advance and efficient systems was always needed.These factors encouraged Raja ram Bojji to invent ACD in the year 1999. Since then this devicehas been developed and tested in different traffic and environmental conditions by installing 552

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ACDs along a 1736 Km long section of Northeast Frontier Railway and 785 mobile ACDs arealso installed in the locomotives and guard vans costing total of Rs 158.67 crore.Reacting on the kasara train collision occurred on July 19,2012 resulting one death and 13injured people, Former Konkan Railway (KR) chairman and inventor of ACDs B Raja ram said“No other country in this world has the ACD and it is our own patent. Had our railways fitted thedevice in all trains, the mishap could have been averted,”The sensors on the device would have alerted the speeding Vidarbha Express train driver andbrought the train to a halt before it collided with the derailed local train. “There is no othertechnology that could have saved the accident,” he added.

Fig-1. TRAIN ACCIDENTS IN INDIA

The device developed by Indian railways can be of divergent use and has great potential to beused in other form of transportation. It not only prevents the collision between trains but alsohelps to maintain their speed and provide information about the location of trains.ACDs also tellsthe driver about other trains on same and nearby tracks, any blockade on the track and also thesituation at unmanned railway crossings.So it can be used as a security system as well as tracking device. With few advancements thissame technology can also be used in road transportation reducing the chances of accidents to agreat extent and also provide the location via GPS reducing the chances of theft.

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3. TECHNOLOGY USED

The heart of the ACD is an Intel 80386 processor that uses the DM&P M617 Intel chipset. It[ACD] has an integrated digital radio modem and works on the VxWorks Real Time OperatingSystem (RTOS). Raja ram adds, “VxWorks, as a platform, is most suitable for real-timeapplications. The main modules of the ACD includes a GPS (Global Positioning System), whichpicks up signals from the constellation of GPS satellites that are being exclusively used for thispurpose. The GPS submits the data to the Command and Control Unit (CCU) to extract theparameters related to the movement of locomotive like latitude, longitude, speed, angle, date andtime. The antenna of the GPS receiver is fitted outside on the roof of the locomotive.

The user-friendly device helps the driver to know the various positions in the form of audio-visual indications, like Station Approach, SOS (for head-on, rear-end and side collisionsituations) and Gate Open. Another module is the radio trans-receiver, which transmits theinformation and commands generated by the CCU and receives the information being sent byother ACDs when the two systems are within the radio-range of 3 km.

The final module in the system is the braking mechanism, which envisages the CCU to take adecision for applying either the normal brake or the emergency brake on the locomotive as thesituation required. "The electro-pneumatic braking is then applied through suitable solenoidinterface installed for this purpose in the cab of the locomotive," the official explained.

ACD is an intelligent friend to the engine driver, which can act on its own without any humanintervention. It comprises a Command and Control Unit (CCU), a GPS Receiver, RadioTransmitter and Crew Interface. The CCU, which is the heart of the ACD, is a microprocessor-based module which processes the data and generates commands. The GPS Receiver picks upsignals from GPS satellites and submits the same to the CCU to extract parameters related to themovement of the locomotive such as latitude, longitude, speed, angle, date and time.

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ACD prevents the head-on collision of two speeding trains, which accidentally happen to be onthe same track. An ACD mounted on a train constantly looks out for signals from another ACDin a 3-km range. The moment both the trains are within the required breaking distance, theACDs, after analyzing the data from the GPS, deduce that they are on the same track and are

Fig- 2. WORKING OF ON-BOARD ACDs

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heading for a collision. Then the ACDs automatically apply the brakes, bringing both the trainsto a halt without the intervention of the driver.

The ACD can be used not only for avoiding head-on collisions but also to detect if a train hasaccidentally stopped on the same track as another, preventing a following train telescoping intoits rear. Also, if two trains are moving on the same track but the separation distance is less than 2km, the ACD will automatically regulate the following train's speed. It can also detect when thebogies of a train from an adjacent track derail on to a train's path. Konkan Railways has testedout 11 accident scenarios with the ACD.

The ACD can be mounted not only on trains but also be installed at railway stations, levelcrossing gates (both manned and unmanned), and on guard vans. If a station is equipped with anACD, the driver will receive the ``station approach'' warning as the train approaches the station.Also, the ACD can sense whether a level crossing gate is open or damaged and warn the driver,besides regulating the train's speed.

4. CONSTRUCTIONAL DETAILS

An anti collision device system for trains and the like transportation system consist of a networkof ACDs one each at locomotives engine (LOCO ACD), guard van (GUARD ACD), station(STATION ACD) and at level crossing gate (GATE ACD) wherein the said locomotive engineand guard van ACD comprising of a microprocessor based central control unit CCU and otherdevices as shown in the flow diagram below where:-

1 Central Control Unit (CCU)

2 Radio Transceiver

3 Global Positioning System (GPS)

4 Power Converter

5 Data Entry Key Pad

6 Automatic Braking Unit

7 Whip antenna (Radio Transceiver)

8 Hard Mount Antenna (GPS Receiver)

9 Crew Interface

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10 I/O Sub System

11 Battery

12 Message Display.

The above figure shows the layout of a Loco ACD which is installed on locomotives, guard vansalso have a similar unit (Guard ACD) and both can be shown and explained using the abovediagram. In these ACDs

Fig-3. FLOW DIAGRAM OF LOCO ACD

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-The CCU is connected to GPS receiver (3), Radio transceiver(2) and console to process inputand take decision the processed output is sent to the radio transceiver(2), crew interface(9)through I/O sub system(10) to take necessary actions.

-GPS receiver is connected to hard mount antenna through cable to give data to CCU regardingits location, speed, and angle etc.

-The radio transceiver is connected to whip antenna through cable to transmit and recieve datafrom/ to CCU(1).

-The power supply is taken from battery and transferred to CCU through power converter.

-The crew interface is connected to CCU through a cable for man-machine interfacing. Thekeypad is connected to CCU through an interfacing cable to feed the data required for working ofdevice.

-Additionally the Loco ACDs are provided with automatic braking unit, which is connected inseries to braking mechanism of locomotive to control the speed as per command received fromCCU and the message display connected to I/O sub system

The STATION and GATE ACDs comprising of a microprocessor based central control unitCCU(1),radio transceiver(2), power converter(4),data entry keypad(5), whip antenna(7) for radiotransceiver and a crew interface(9). The GPS unit with its hard mount antenna is missing in theseACDs.A schematic diagram of ACDs used on stations and level crossing gates is shown below. All theconnections and working is similar to Loco ACDs the only difference being the absence of GPSunit in Station ACDs.

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Fig-4. FLOW DIAGRAM OF STATION ACDs

5. WORKING OF ACDs IN INDIAN RAILWAYS

The loco A.C.D is the heart of A.C.D network. In the A.C.D the radio single from theconsolation of Global Positioning satellite (G.P.S) System are received by GPS receiver throughantenna. This signal is sent to the command and control unit that is C.C.U. of the ACD. TheC.C.U is micro processor based module. And is like a brain of the A.C.D system.

The GPS submits the data to the Command and Control Unit (CCU) to extract the parametersrelated to the movement of locomotive like

v Latitude.v Longitude.v Speed.v Angle.v Date and time.

Fixed inside station building

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It processes the data and generates the command from the A.C.D. Apart from the GPS receiverthere is a radio Trans- receiver inside the ACD which transmits information such as:

v Identification no.v Speedv Location in terms of Latitude, Longitude, and status of its working with the help of sprats

radio antenna.

Fig-5. UNIT FOR LOCOMOTIVE (L:- 435 X, W:- 203 X, H:- 342 MM)

It also receives the information being sent by other ACD within range of 3 Km. This informationis also sent to the C.C.U. for processing all received information from the other ACD and thedata from the GPS receiver. The C.C.U unit takes a decision for applying either a normal &emergency break or the locomotive break as the case may be.

This is activated with the help of the auto breaking unit of the loco.Onboard mobile loco ACDand guard room ACD have both a GPS receiver and radio trans- receiver. The GPS receiver

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receives the data from the satellite and radio trans receiver communicate with the other GPSWithin a range of 3 Km. The tracks side and states nearby module. Such as :- station ACD, levelcrossing ACD, and loco ACD.

Both mobile and stationary ACD exchange information and take decision based on trans workingrule and embedded software to apply breaks automatically without any input from users. All theACDs work on the principle of distributed control system which is very simply. If two ACD onlocomotive are within pre define distance and proceeding towards each other and there is risks ofcollision the system automatically activates the breaking of the train and prevents collision.

Fig-6. ACD NETWORK

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6. FEATURES OF ACD

The principal object of the present invention is to overcome the disadvantages and provide an anti-collision safety device for vehicles travelling on tracks, without any driving personnel, that is to say,a device which itself can estimate risks and react in consequence.

More generally, the invention is intended to provide a device comprising means of observation andmaking decisions for safe operation, using in particular the principle of deformable movable blocks.

To this end, the present invention relates to an anti-collision safety device of the type indicatedabove, characterized in that it comprises means for detecting and counting reference points providedalong the track, means for calculating the distance of a vehicle from a given zero point, and meansfor converting this distance into a time reference constituted by a synchronization pulse received byall the vehicles. The device further comprises means for generating a series of position pulses,emitted by all the vehicles and received by all the vehicles, the distance between a vehicle and thevehicle immediately preceding it being determined by comparing the position pulses; further, thesafety device of each vehicle compares this relative distance with its stopping distance and causesthe vehicle to stop when the relative distance is smaller than the stopping distance.

According to another characteristic feature of the invention, the stopping distance is determinedfrom the actual speed of the vehicle, which may be obtained by a tachometer (e.g., a phonic wheel)supplying speed signals to a function generator which is initialized by the position pulse and whichfurnishes an output signal as soon as the function generator has reached the actual vehicle speed, thevehicle being caused to stop if the signal from the function generator does not lie within the distancebetween the vehicle and the vehicle immediately preceding it (relative distance window).

According to another characteristic feature of the invention, an alarm is given by a position alarmdevice set off separately or in combination by a breakdown of the reference point detector, abreakdown of the reference point counter, or a transmission breakdown. This alarm is transmitted tothe central control station (PCC) by the emission of a pulse characteristic of a vehicle, and thecentral station PCC then distributes a general brake or line emergency stop signal that stops allvehicles on the line.

According to another characteristic feature of the invention, the safe operation of the loop functions(calculation of position, calculation of stopping distance) is controlled by the signals supplied byduplicate breakdown detecting circuits, the output signals from the means checking for intrinsicsafety the coincidence of the output signals of the duplicate circuits, the absence of coincidencecharacterizing a breakdown or a risk of collision and causing stopping.

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7. FUNCTIONS OF ACD:-

v Continues communication: - All ACDs within a radius of three kilometers continuouslycommunicate among themselves giving their ID, status, location, speed, etc.

v Detection and Prevention of Head-on, Rear-end and Side Collisions: –It is the onlysystem in the world to provide these UNIQUE features even when a train is not protected bya signal, as in a block section.

v Detection of fouling and prevention of collision due to fouling:- When a Train on mainline overshoots the ‘Fouling Mark’, this system activates and prevents collision due tofouling.

v Detection & generation of Train parting / Jumbling: - Consequently bringing anyapproaching train on the adjoining line to a dead stop.

v Station Approach Warning to Drivers: - Can result in saving of Manpower for deploymentof detonators during foggy weather, provided 100% coverage of ACD fitted trains isavailable on the concerned ACD route.

v Speed limit imposition:- It limits the train speed to 30 kmph near stations and unmannedlevel crossing if the gate is detected as open. Mostly the speed limit is based on ‘preset’conditions in FRS of ACD.

v ‘Train Approach’ Warning for road users :-It provide warning at both manned andunmanned level crossings. In addition, at manned non-interlocked level crossings, reducingthe train speed to 30 Kmph in case the gate is detected in ‘open’ condition through GateACD.

v Manual SOS functionality available for Drivers, Guards and Station Masters: - To bringall trains to a halt within a radial distance of 3 Kms, in emergencies.

v Auto Brake Test:- Generating braking characteristics for a Train ‘without manual feeding’of data of coaches / load - A UNIQUE feature as train characteristics are required to be fed‘manually’ in all other systems in the world.

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8. NON-PREVENTABLE ACCIDENTS EVEN WITH ACDS:-

An analysis of ‘preventable’ and ‘non-preventable’ accidents by Safety Directorate of RailwayBoard of a total of ‘128 train collisions on Indian Railways’ during the five years period namely,from April 1997 to January 2002, indicated that 82% of these collisions were preventable byACD. The balance 18% of the collisions were ‘non-preventable’ in any case due to variousreasons like failure of brake power of train, inadequate reaction time, insufficient brakingdistance, etc.

Various collisions/situations which are not preventable in any case, with or without ACDnetwork, are enumerated below:

v Other train is a ‘NON’ ACD Train – ACD functions by reacting to another ACD, as suchif one of the two trains is a non-ACD train, the protection against collision will be missing.

v ‘Adequate’ braking distance at that speed is not available when a ‘dangerous’ collision-like situation arises suddenly – However, severity of the collision would be reduced as afunction of the reaction time.

v Train derails and its wagons/coaches dash with another Train, already on ‘adjacent’track – In situations like this there is no reaction time and the damage has already been donebefore the train reaches a halt. These situations are known as Zero reaction time situation.

v Presence of Cracks on track – This technology has not yet been developed to detect crackson railway tracks. So, ACDs won’t be functional or provide assistance in this situation.

v ‘Failure’ of brake power of the Locomotive/train – It’s a very rare situation but if brakesof a loco fails due to reason like air leakage then even if an emergency occurs the ACDs willnot be able to stop the train.

v Rolling backward/forward of a ‘Stabled load’.

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9. DEFICIENCIES IN ACDs :

The ACD system is based on GPS based positioning and track detection. This had its inherentproblems as with the GPS- Standard Positioning GPS service or Coarse acquisition ( Precisionpositioning is only available in US for military use )the best possible horizontal accuracy is 10m.This is inadequate for detection of rail tracks separated by a distance of 10–15 feet. ACD doesnot even have DGPS (Differential GPS that gives an accuracy close to 2.5m ) and hence haderrors in track detection using their patented Deviation Count Theory that worked in blocksections but failed in station sections. The result was erratic breaking that disrupted trainmovements and proved to be ineffective.

Railways has been unable to develop a robust and reliable anti-collision device to prevent trainmishaps despite carrying out field trials for over a decade, the Comptroller and Auditor Generalhas observed in its latest report.

The device's field trials are being carried out since 2000-01 and site acceptance tests andmodifications are being done since November, 2006 in the 1,736 km-long Katihar-Guwahati-Ledo/Dibrugarh section of Northeast Frontier Railway at a cost of Rs 158.67 crore.

"But despite the long trial, a reliable anti-collision device (ACD) is yet to be developed so far.The ACD was not in a position to judge whether the inputs derived from the signalling systemswere dependable," the report pointed out.

It also noted out that there was no system to detect whether the ACD installed in locomotivesand guard vans were defective or not.

Similarly, the CAG has found despite commissioning of the train protection warning system(TPWS) in Southern Railway as a measure to prevent accident in May 2009 at a cost of Rs 49.49crore, the trial reports indicated various failures of the equipment requiring modifications in thesoftware.

"The performance efficiency recorded during trials was between 77 and 90 per cent as againstthe acceptable level of 99.9 per cent...The TPWS work commenced in 2005 in North CentralRailway had not yet been completed despite incurrence of expenditure of Rs 41.54 crore," thereport said.

The CAG has found that out of total 552 ACD installed at stations and level crossings bothmanned and unmanned, 188 were either defective or were not working in account of theft ofsolar panel provided for charging the batteries of the devices.

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Besides, 37 mobile ACDs out of 785 provided in the locomotives and guard vans were also lyingdefective. The total expenditure incurred on supply and installation of ACDs as well as actualoperation and maintenance incurred up to June 30 last year was Rs 158.67 crore, out of whichthe annual maintenance costs accounted for was Rs 66.08 crore.

The Audit found that as actual ACD coverage was not available to two-third of the passengertrains and more than 50 per cent of freight carrying trains, the risk of averting collision was moreor less the same even after incurrence of expenditure of Rs 158.67 crore.

Referring to the decision for extension of ACD coverage to other zones including Southern ,South Central, South Western, Eastern, East Central, East Coast and South Eastern Railway, theAudit found that there was negligible progress in the installation and commissioning of works inthese zones.

10.TECHNICAL ADVANCEMENT IN ACD

Anti Collision Device (ACD), which is an on-board train protection device and also the first everdevice in the world indigenously developed by Konkan Railway with their Technical PartnerKernex Microsystems (I) Ltd, will be in place by 2013 on the entire Indian Railway network soas to reduce chances of Train collisions.

A new ACD Version-II [now called Train Collision Avoidance System (TCAS)] is underdevelopment by the Research Designs and Standards Organisation (RDSO). Unlike ACD whichis more of a distributed system which acts independently, the TCAS will be more of a centralizedsystem where in Station TCAS controls communication between locos and with locos withTDMA protocol. The TCAS under development is meant to be a vital safety system meaningTCAS have a deep coupling with Railway's signalling system whereas ACD systems does notdepend on Railway's signalling system. The design ruled out GPS as it was a 3rd party system(US based) and suggested track based sensors similar to RFID (Radio Frequency IdentificationDevice) or Balise (similar to the EuroBalise).

After 7–8 years of problems with the ACD system, RDSO, Lucknow drafted the TCAS (TrainCollision Avoidance System) specs. With amendments that followed and finally in 2012, theVer3.1.1 spec. has been released (after joint consultation with companies manufacturingsignaling equipment for the Indian Railways). TCAS being developed by qualified companies(RDSO approved and manufacturing railway safety systems that includes, Medha Servo DrivesHyderabad, Invensys Bangalore, Siemens, HBL Power Systems Ltd Hyderabad and others) inIndia selected by RDSO through an Expression of Interest (EOI), shall be an Indian TrainProtection System offering collision avoidance and also offer many functionalities of theEuropean Train Control System that includes prevention of Signal Passing at Danger(SPAD),Movement Authority and Control, Critical Train Data Recorder, advance in cab display ofsignals, advance alerts and warnings from Station sections, uploading of running train data to aCentral Train Management System over GSM-GPRS,etc.

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On 16th Oct 2012 this system was successfully tested about 150 km from Hyderabad. A host ofrailway officials led by Chairman of the Railway Board Vinay Mittal, Member (Electrical) KulBhushan and Director General of the Research Designs & Standards Organization (RDSO),Lucknow, V. Ramachandran watched the successful trial of the TCAS. The test was conductedby running two trains, fitted with modified and most advanced TCAS technology equipment, inthe opposite directions on the same track at 60 kmph and with a train coming from behind into astationary one between Mantatti and Navandgi stations. Both the trains screeched to a halt at adistance of about 200 meters as the officials watched the moment with bated breath.Interestingly, all the senior railway officials were sitting in the moving train which approachedthe stationary one from behind. Mr. Mittal said: “It is a path-breaking technology and we willcomplete all the trials within a year. The TCAS has more capabilities than the technologies beingused in many advanced countries.” The test was absolutely successful, he added. Mr.Ramachandran said the technology with some limited options would be introduced in somesections within six months.

Fig-7. WORKING OF TCAS

The approximate size of Station TCAS would be two 19”rakes of about 5-6’height. TCAS wouldnot only help avoid collisions due to human errors in signaling and invisibility of signals due to

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heavy rain or fog, but alerts about fire on trains and warns about damage to the tracks duringnatural calamities or sabotage.

The proposed design of TCAS has a data logger in which all the data will be saved. The storagecapacity of this data logger will be minimum 90 days for Loco TCAS and 30 days for StationTCAS. Information to be logged in data logger is mentioned below:

(a) LOCO TCAS:

Event, date& time, Loco Id, speed, location, last RFID tag passed, direction, block or stationsection, type of brake application, brake release, emergency message, any other.

(b)STATION TCAS:

Event, date, time, status of all signalling inputs, signalling information packet, stationemergency message, Loco’s emergency message(redirected),message to adjacent stationaryTCAS, any other.

This information will be logged in each record in every 1 second and will trigger on occurrenceof following events:

(a) LOCO TCAS:

Initiation of braking application, change of type of brake application, removal of brakeapplication, change in mode, acknowledgement by driver, SPAD, passing of RFID tag,change in TIN, one RFID missing out of two, data mismatch between duplicate RFID tag,change of signal aspect, passing of signal, permission of emergency messages, reception ofemergency message, collision like situation, any other event.

(b) STATION TCAS:

Entry of new train, change in input to station TCAS from interlocking, emergency messagesreceived from Loco TCAS, transmission of emergency message either generated by stationitself or retransmission of such messages received from Loco TCAS, Block entry, block exit,any other event.

In the description of TCAS the method to calculate the distance available for stopping of trains isalso described which differ for Head on and Rear end collision.

(a) FOR HEAD ON COLLISION:

Let S1 be the speed &L1 be the location of Loco-1 and S2 be the speed & L2 be the location ofLoco-2. The direction is opposite to each other and the TIN is same as they are approaching headon.

The distance b/w the two Locos, D= |L1-L2|

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& D shall be divided b/w them such that

D = D1 + D2 + 200m (200m is the safety margin when two trains have stopped)

(D1/D2) = (S1/S2)2

Where D1 is the distance available for Loco-1 to stop & D2 is same for Loco-2.

(b) FOR REAR END COLLISION:

Assuming Loco-1 is the train ahead & Loco-2 is following it from behind. Let TL1 is the trainlength of Loco-1. There shall be no target to stop for Loco-1 on account of Loco-2 coming frombehind. The distance available for Loco-2 to stop, D2 may be as under:

D2 = |L1-L2|-TL1-200m.

The distances D1 & D2 shall be calculated and speed profile calculated/ updated dynamically &the braking shall be initiated or changed to higher level by Loco-1 or Loco-2 trains according todynamically updated speed profile/ brake curve.

11. FEATURES OF ACD

v Very economical and cost effective.v Easily adaptable and expandable.v Acts automatically to prevent collisions if an eventuality arises.v Does not degrade the existing safety level.v Employs state-of-art hardware and software technology.v No way had side equipment required, hence no requirement of Power.v No cabling on the track required (which is more expensive and cumbersome) .v Less susceptible to Vandalism.v It does not require any inputs to be fed by the crew at the start of journey, thus human error is

eliminated.

12. APPLICATIONS:-

v ACDs can be implemented in railways to prevent collisions and to increase the tolerancebetween two consecutive trains running one after another.

v Development of high speed trains with high safety measures.v It can be used in heavy vehicles like cranes, earthmovers etc to prevent accidents and for

their safe working in public places.v With few developments can also be used in automobiles for prevention of road accidents.v ACDs can be used as a tracking device.

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SUMMARY

The ACD is a path- breaking technology which has high potential for development and can betransformed to be used in almost all modes of transportation. With its trials for the last ten yearsthe problems or faults are discovered and being removed out. The recent trial phase has shownsatisfactory results with the development of ACD version II also known as Train CollisionAvoidance System (TCAS). This new system seems to be very promising as far as trails areconcerned. TCAS not only have better efficiency but also have some advance features like speedand signal warning to the driver, improved train length calculation, improved state of the arthardware and software, continuous communication between locos etc.

TCAS would not only help avoid collisions due to human errors in signaling and invisibility ofsignals due to heavy rain or fog, but alerts about fire on trains and warns about damage to thetracks during natural calamities or sabotage.

This system designed by Indian railways is the only system of its kind which prevents collisions,provide warnings, location, speed of loco to driver while simultaneously communication withother systems.

The trials of TCAS will be completed this year and if the results of trails are as desired then theinstallation of TCAS will start at full scale.

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REFERENCES

v www.google.comv www.konkanrailways.gov.inv www.wikipedia.orgv www.ipindia.nic.in (Controller General of Patents Designs and Trademarks)v www.railjournal.comv www.cag.gov.in (Report on Disaster Management in Indian Railways)v http://railwaymodel.infov http://www.ijetch.org (IACSIT International Journal of Engineering and Technology)v www.dnaindia.comv www.thehindu.comv www.timesofindia.indiatimes.comv www.indianexpress.comv www.rediff.com/anti_collision_devices.htmlv www.ask.comv www.hindustantimes.com/acd.htmlv www.rdso.indianrailways.gov.in (Research Design and Standards Organization)v http://www.youtube.comv www.kernex.inv http://zeenews.india.comv http://www.anticollisionsystems.blogspot.inv http://ebookbrowse.comv Indian Railways Annual Report and accounts.