report on ACD (anti collision devices) in IEEE format by Tarun Khaneja ( 9034406598 )

1. A
Seminar Report On
Anti Collision Device
(ACD)
Submitted to: Submitted by:
Er. Shallu Garg Tarun Khaneja
(Lect. of Ece Deptt.) 2110045
ECE
Department of Electronics & Communication Engineering
Doon Valley Institute of Engineering & Technology
Karnal- Haryana
(March - 2014)

2. Anti Collision Devices
Tarun Khaneja
Electronics & comm. Engg.
Doon Valley Institute of Engg. & Tech.
Karnal, Haryana
Tarun4568@gmail.com
Introduction
The ACD Network is a Train Collision prevention
system invented by Rajaram Bojji and patented
by Konkan Railway Corporation Limited (A Public
Sector Undertaking of Ministry of
Railways, Government of India). ACDs have
knowledge embedded intelligence. They take
inputs from GPS satellite system for position
updates and network among themselves for
exchanging information using their data radio
modems to take decisions for timely auto-
application of brakes to prevent dangerous
'collisions', thus forming a 'Raksha KavachTM
'
(meaning a '(Train) Safety shield').
ACDs fitted (both in Locomotive and Guard's Van
of a train) act as a watchdog in the dark as they
constantly remain in lookout for other train bound
ACDs, within the braking distance required for
their relative speeds. They communicate through
their radios and identify each other. If they happen
to find themselves on the same track and coming
closer to each other, they automatically restrain and
stop each other, thereby preventing
dangerous head-on and rear-end collisions.
Loco ACD of a train also applies brakes to reduce
the train speed either to 15 km/h if on approach it
receives a message from other train bound ACD
that has stopped in a block section on adjacent
track (and driver of that train has yet not
communicated that things are 'Normal') or to bring
the train to a stop if train bound ACDs of other
train are radiating 'train parted' message thereby
preventing dangerous side collision that may occur
due to infringement of adjacent track by a stopped
or a 'parted' train, respectively.
The ACDs are capable of multi functions. For
example, while approaching a station, the Loco
ACD gives the "station approach" warning to the
driver about 2 km in rear of the first STOP signal
of the station and in case the driver ignores the
warning it will automatically regulate it.
Need of A.C.D.
The main modules of the ACD includes a GPS
(Global Positioning System), which picks up
signals from the constellation of GPS satellites that
are being exclusively used for this purpose. The
GPS submits the data to the Command and Control
Unit (CCU) to extract the parameters related to the
movement of locomotive like latitude, longitude,
speed, angle, date and time. 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 collision situations) and Gate
Open. Another module is the radio trans-receiver,
which transmits the information and commands
generated by the CCU and receives
the information being sent by other 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 a
decision for applying either the normal brake or the
emergency brake on the locomotive as the situation
required. "The electro-pneumatic braking is then
applied through suitable solenoid interface 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 human
intervention. It comprises a Command and Control
Unit (CCU), a GPS Receiver, Radio Transmitter
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 up signals from GPS
satellites and submits the same to the CCU to
extract parameters related to the movement of the
locomotive such as latitude, longitude, speed,
angle, date and time.
ACD prevents the head-on collision of two
speeding trains, which accidentally happen to be on
the same track. An ACD mounted on a train
constantly looks out for signals from another ACD
in a 3-km range. The moment both the trains are
within the required breaking distance, the ACDs,
after analysing the data from the GPS, deduce that
they are on the same track and are heading for
a collision. Then the ACDs automatically apply the
brakes, bringing both the trains to a halt without
any of the intervention to the driver.
Working Of ACD
„ACD Network‟ consists of mobile ACDs and
trackside ACDs Mobile ACDs take inputs from
GPS satellite system for position updates and
Jennic, JN-AN-1059 Deployment guidelines for

3. IEEE 802.15.4/ZigBee wireless networks, 37-38,
2007.
Fig.1 ACD At Locomotive Of The Train
„ACD Network‟ is likely to prevent „head-on‟ and
„rear-end‟ collisions in mid-sections, collisions at
„high speed‟ in „station area‟, „side collisions‟ with
derailed vehicles obstructing adjacent line,
collisions due to „train parting / jumbling‟ and
collisions with „road vehicles‟ at level crossing
through „Train Approach‟ warning and detection of
„Gate Open‟. Loco ACDs also give „Station
Approach‟ warning to drivers. Moreover, using
Manual „SOS‟ buttons on their ACDs, Drivers,
Guards and Station Masters can also „stop‟ trains
when any unusual is detected.
Fig.2 Anti Collision Devices
Fig.3 Konkan railway Corporation
limited (A PSU of ministry of Railways)
Benefits of the ACD system
1. Very economical and cost effective.
2. Easily adaptable and expandable.
3. Does not degrade the existing safety level.
4. Employs state-of-art hardware and software
technology.
5. No way had side equipment required, hence no
requirement of Power
.6. No cabling on the track required (which is more
expensive and cumbersome).
7. Less susceptible to Vandalism.
8. It does not require any inputs to be fed by the
crew at the start of journey, thus human error is
eliminated.
9. Maintenance Support System (MSS)
10. Daily Reports of incidences of Warning to the
Driver due to Gate OPEN or Obstruction.
11. Date wise Report of incidences of Warning to
the Driver due to Gate OPEN or Obstruction.
12. Daily Maintenance Report of Failure of Loco
Unit and Gate Unit.
13. Date wise Maintenance Report of Failure of
Loco Unit and Gate Unit.
Features of ACD
The principal object of the present invention is to
overcome these 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
and making decisions for safe operation, using in
particular the principle of deformable movable
blocks.

4. To this end, the present invention relates to an anti-
collision safety device of the type indicated above,
characterized in that it comprises means for
detecting and counting reference points provided
along the track, means for calculating the distance
of a vehicle from a given zero point, and means for
converting this distance into a time with a time
reference constituted by a synchronization pulse
received by all 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
the vehicle immediately preceding it being
determined by comparing the position pulses;
further, the safety device of each vehicle compares
this relative distance with its stopping distance and
causes the 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 determined from
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 which
furnishes an output signal as soon as the function
generator has reached the actual vehicle speed, the
vehicle being caused to stop if the signal from the
function generator does not lie within the distance
between 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 alarm
device set off separately or in combination by a
breakdown of the reference point detector, a
beakdown of the reference point counter, or a
transmission breakdown. This alarm is transmitted
to the central control station (PCC) by the emission
of a pulse characteristic of a vehicle, and the central
station PCC then distributes a general brake or line
emergency stop signal that stops all vehicles on the
line.
Applications
1. ACDs can be implemented in railways to prevent
collisions and to decrease the timing between two
consecutive trains running one after another.
2. It can be used in heavy vehicles like cranes,
earthmovers etc to prevent accidents and for their
safe working in public places.
3. ACDs can be used as a tracking device.
4. It can be used to get position of vehicles.
Future Scope of ACD
Pilot project of "Provision of ACD Network" has
been successfully commissioned recently on the
Northeast Frontier Railway (of Indian Railways),
covering 1736 Route km (of its Broad Gauge
route). Final commissioning trials of ACD network
installed on 760 km of Konkan Railway route is
presently underway.
Anti Collision Device (ACD), which is an on-board
train protection device and also the first ever device
in the world indigenously developed by Konkan
Railway with their Technical Partner Kernex
Microsystems (I) Ltd, will be in place by 2013 on
the entire Indian Railway network so as to reduce
chances of Train collisions.
A new ACD Version-II [now called Train Collision
Avoidance System (TCAS)] is under development
by The Research Designs and Standards
Organisation (RDSO). Unlike ACD which is more
of a distributed system which acts independently,
the TCAS will be more of a centralized system
where in Station TCAS controls communication
between locos and with locos with TDMA
protocol. The TCAS under development is meant to
be a vital safety system meaning TCAS have a
deep coupling with Railway's signalling system
where as ACD systems does not depend on
Railway's signalling system.
References
1. Shival Dubey & Abdul Wahid Ansari PDF on
ACD.
2. Signal and Telecommunication dept. of Konkan
Railway Corporation Limited.
3. Arun.P,Saritha.S,K.M.Martin,Madhukumar.S
“Simulation of zigbee based TACS for collision
detection and avoidance for railway traffic.,” in
International conference on advanced
computing & communication technologies for
high performance application,paper ID 51,June
2012.
4. Bhatt, Ajaykumar A, „An Anti-Collision Device
(ACD) Network – A train Collision Prevention
System (TCPS)‟.
5. David Barney David Haley and George
Nikandros: Calculating Train Braking Distance,
Signal and Operational Systems Queensland
Rail PO Box 1429, Brisbane 4001, Queensland,
Australia
6. K. Shuaib, M. Boulmalf, F. Sallabi and A.
Lakas, “Co-existence of Zigbee and WLAN-a
performance study”, IFIP International
Conference on Wireless and Optical
Communications Networks, pp. 5, 2006.
7. Muhammad Ali Mazidi, Rolin D. McKinlay,
Danny Causey :PIC Microcontroller and
Embedded Systems, PE India, 01-Sep-2008.
8. Signal Engineering Manual, Indian Railway
Institute of Signal Engineering and
Telecommunication.