This document provides information about Prabjeet Singh's 4 week summer training at the Electric Loco Shed in Tughlakabad, New Delhi from May 25 to June 22, 2016. It includes an acknowledgements section thanking various supervisors and colleagues for their support. The abstract summarizes that the shed was established in 1988 and maintains WAG9, WAM4 and WAP7 electric locomotives that operate on the New Delhi to Bombay route.

1. Summer Training
at
Electric Loco Shed, Tughlakabad, New Delhi
25 May 2016-22 June 2016

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University College of Engineering, Rajasthan Technical University, Kota
Website: www.rtu.ac.in , Electrical Engineering Department
Session 2015-16
Project Report on Summer Training at Electric
Loco Shed
WCR, Tughlakabad, New Delhi
Submitted By:
Prabjeet Singh (13EUCEE060)
BACHELOR OF TECHNOLOGY
ELECTRICAL ENGINEERING
Department of Electrical Engineering
Rajasthan Technical University, Kota

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ACKNOWLEDGEMENT
Every projectbig or small is successfullargely due to the effort of a number of wonderful
people who have always given their valuable advice or lent a helping hand. I sincerely
appreciate the inspiration, supportand guidance of all thosepeople who have been there in
making this project and our summer training a successful one.
I am extremely gratefulto the “Electric LocoShed, WCR, Tughlakabad, NewDelhi” for the
confidence bestowed in me and allowing me to held the summer training in the duration 25
May 2016 to 22 June 2016.
At this junctureI feel deeply honored in expressing my sincere thanks to Mr. S.P Singh& Mr.
DilipAgarwal for making the resourceavailable at right time and providing the valuable
insights leading to the successfulcompletion of my project.
I express my gratitude to Mr. Jeet Shyam Singh for arranging the summer training in good
schedule. I also extend my gratitude to my project guide, who assisted me in compiling the
project.
I would also like to thank all the faculty members of University College of Engineering,
Rajasthan Technical University, Kota for their critical advice and guidance without which this
projectwould havenot been possible.
Last but not the least I place a deep senseof gratitude to my family members and my friends
who have been a constantsourceof inspiration during the preparation of this project.
DATE :22 JUNE 2016
PLACE :Tughlakabad, New Delhi

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ABSTRACT
This shed is a West Central Railway shed on Northern Railway territory!Itbelongs to the Kota
division. This shed was established in 1988 and was a Western Railway shed until 2003. This
shed was originally built to handle locos for the freight traffic on the busy New Delhi - Bombay
route. Has received a few WAG9 starting 02/08. Starting 2010 received WAM-4 locos to be
operated in pairs on container trains. WAP-7 locos homed here in 2013 195+locos.
The focus of the detailed study of this electric loco shed is to understand the working of the
organization as well as to understand the functioning of the engine and various parts used to
achieve the traction. Safety and systemreliability concerns dominate in this domain. With such
motivation various issues aretackled related to the improper functioning of the loco or the
complete failure of the loco.

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TABLE OF CONTENTS
CHAPTER 1: INRODUCTION
 About Indian Railways 7
 Genesis of Indian Railways 9
 Other milestones 10
 The need for a Railway network 11
 Electric Loco Shed, Tughlakabad 11
CHAPTER 2: OVERVIEWOF SECTIONS 16
CHAPTER 3: CLASSIFICATION OF LOCOMOTIVES 18
CHAPTER 4: CONTACTOR SECTION
 Electromagnetic Contactor 19
 Electro pneumatic Contactor 20
 DrumContactor 20
 Cam Contactor 21
 Principle of Contactor 22
 Tap Changer 22
CHAPTER 5: RELAY SECTION 26
CHAPTER 6: TRACTION MOTOR SECTION
 Working 28
 Types of DC motors 28
 Advantageof DC series motors 28
 Traction Motors 29
CHAPTER 7: BOGIESECTION
 Bogie Classification 31
 Bogie Components 32
 CO-CO Tri mount Bogie 32
 Tetra mount high adhesion Bogie 33
 Bogie components arrangement 34

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CHAPTER 8: COMPRESSOR AND EXHAUSTER SECTION
 Introduction 37
 ARNO Converter 37
CHAPTER 9: PANTOGRAPH SECTION
 Introduction 41
 Principle 41
 Raising 42
 Lowering 42
 Reasons for using the rear panto 42
CHAPTER 10:MOH SECTION 44
CHAPTER 11:PNEUMATIC SECTION (BRAKING)
 Air brake 45
 Vacuumbreak 45
CHAPTER 12:POWER SECTION
 Transformer 47
 Vacuumcircuit breaker 48
 Potential transformer 48
 Harmonic filter 50
 Battery 50
CHAPTER 13:ELECTRONICS SECTION
 CHBA 51
 180 kV SIV Converter 51
 Traction converter 52
 Silicon Rectifier 53
CHAPTER 14:WHEEL SECTION 54
CHAPTER 15:LAYOUT OF LOCOMOTIVE
 Bogie layout 55
 Roof layout 56

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 Cab layout 57
 Machine room for WAG9/WAP7 58
 Machine room for WAP5 59

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CHAPTER 1: INTRODUCTION
1.1 About Indian Railways
Indian Railways, a historical legacy, are a vital force in our economy. The firstrailway on
Indian sub-continentran fromBombay to Thane on 16th April 1853. Fourteen railway
carriages carried about 400 guests fromBombay to Thane covering a distance of 21 miles
(34 Kilometers). Since then there has been no looking back. Today, it covers 6,909 stations
over a total route length of more than 63,028 kilometers. Thetrack kilometers in broad
gauge (1676 mm) are86, 526 kms, meter gauge (1000 mm) are18, 529 kms and narrow
gauge (762/610 mm) are3,651 kms. Of thetotal routeof 63,028 kms, 16,001kms are
electrified. The railways have8000 locomotives, 50,000 coaching vehicles, 222,147freight
wagons, 6853 stations, 300 yards,2300 good sheds,700 repair shops, and 1.54 million
work force. Indian Railways runs around 11,000 trains every day, of which 7,000 are
passenger trains. Presently, 9 pairs of Rajdhaniand 13 pairs of Shatabdi Express Trains run
on the rail tracks of India.
Itis interesting to note that though the railways wereintroduced to facilitate the
commercial interest of the British, it played an important role in unifying the country.
Railways are ideally suited for long distance traveland movement of bulk commodities.
Regarded better than road transportin terms of energy efficiency, land use, environment
impact and safety it is always in forefrontduring national emergency.
Indian railways, thelargest rail network in Asia and the world’s second largestunder one
management are also credited with having a multi gauge and multi traction system. The
Indian Railways havebeen a great integrating force for more than 150 years. Ithas helped
the economic life of the country and helped in accelerating the development of industry
and agriculture. Indian Railways is known to be the largest railway network in Asia.
The Indian Railways network binds the social, cultural and economic fabric of the
country and covers the whole of country ranging fromnorth to south and east to west
removing the distance barrier for its people. The railway network of India has brought
together the whole of country hence creating a feeling of unity among Indians.

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1.1.1 OrganizationOverview
The Ministry of Railways under Governmentof India controls Indian Railways. The
Ministry is headed by Union Minister who is generally supported by a Minster of State.
The Railway Board consisting of six members and a chairman reports to this top
hierarchy. The railway zones are headed by their respectiveGeneral Managers who in
turn reportto the Railway Board. For administrative convenienceIndian Railways is
primarily divided into 16 zones:
Table 1: Railway Zones and their Headquarters
1.1.2 The Ministry of Railways has following nine undertakings:
1. Rail India Technical& Economic ServicesLimited (RITES)
2. Indian Railway Construction (IRCON) InternationalLimited
3. Indian Railway Finance Corporation Limited (IRFC)
4. Container Corporation of India Limited (CONCOR)
5. Konkan Railway Corporation Limited (KRCL)
6. Indian Railway Catering & Tourism Corporation Ltd (IRCTC)
7. Railtel Corporation of India Ltd. (Rail Tel)
8. MumbaiRail VikasNigam Ltd. (MRVNL)
9. Rail VikasNigam Ltd. (RVNL)
Indian Railways havetheir research and development wing in the formof Research,
Designs and Standard Organization (RDSO). RDSO functions as thetechnical advisor and
consultantto the Ministry, Zonal Railways and Production Units.
1.1.3 Rolling stock
Today, Indian Railways havebecome self-reliantin production of rolling stock. It
supplies rolling stock to other countries and non-railway customers. Theproduction
units are at Diesel Locomotive Works, Varanasi, Chittaranjan LocomotiveWorks
Chittaranjan, Diesel-Loco Modernization Works, Patiala, IntegralCoach Factory,

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Chennai, Rail Coach Factory, Kapurthala, Wheel & Axle Plant, Bangaloreand Rail Spring
Karkhana, Gwalior.
1.1.4 Indian Railway Catering and TourismCorporation(IRCTC)
IRCTC has launched on line ticketing facility with the aid of Center for Railway
Information System, which can be booked on www.irctc.co.in. For theconvenience of
customers queries related to accommodation availability, passenger status, train
schedule etc are can all be addressed online. Computerized reservation facilities have
made the life easy of commuters across India.
NationalTrain Enquiry system is another initiative of Indian Railways which offers train
running position on a currentbasis through various outputdevices such as terminals in
the station enquiries and Interactive Voice Response Systems (IVRS) atimportant railway
stations.
Indian Railways are committed to provideimproved telecommunication systemto its
passengers. For this Optical Fiber Communication (OFC) system has been embraced,
which involves laying optical fiber cable along the railway tracks. In recent years Indian
Railways have witnessed the marked rise of collaboration between private and public
sectors. Few of the notable examples here are the broad gaugeconnectivity to Pipya
Portwhere a joint venture company is formed with Pipava Portauthority. Similarly
Memorandums of Understanding has been signed between Railways and State
governments of Andhra Pradesh, Karnataka, Maharashtra, WestBengal, Tamil Nadu and
Jharkhand.
1.2 Genesis of Indian Railways
The story of the Indian Railways (IR) is not justa saga of mundane statistics and miles of
rolling stock. Itis the glorious tale of a pioneering institution that has blazed a trail for
nearly a century and a half, making inroads into far-flung territory and providing a means
of communication.
Indian Railway is one of India's mosteffective networks that keep together the social,
economic, political and cultural fabric of the country intact. Be it cold, mountainous terrain
or the long stretches through the Rajasthan desert, Indian Railways cover the vast expanse
of the country fromnorth to south, east to west and all in between.

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More than a hundred years ago, on the 16 April 1853, a red-letter day appeared in the
glorious history of the Indian Railways. On the day, the very firstrailway train in India ran
over a stretch of 21 miles fromBombay to Thane. This pioneer railway train consisting of
14 railway carriages carrying about400 guests, steamed off at 3:30 pm amidst the loud
applauseof a vast multitude and to the salute of 21 guns. Itreached Thane at about 4.45
pm. The guests returned to Bombay at 7 pm on the next day, that is, April17. On April 18,
1853, Sir JamsetjeeJeejeebhoy, Second Baronet, reserved the whole train and traveled
fromBombay to Thane and back along with some members of his family and friends. This
was the humble beginning of the modern Indian Railway systemknown today for its
extraordinary integration of high administrativeefficiency, technical skill, commercial
enterprise and resourcefulness. Today theIndian Railway (IR) is one of the most
specialized industries of the world.
1.3 Other Milestone
Under the British East India Company's auspices, theGreat Indian Peninsula Railway
Company (GIPRC) was formed on July 15, 1844. Events moved at a fastpace. On October
31, 1850, theceremony of turning the first sod for the GIPRCfromBombay to Kalyan was
performed. The opening ceremony of the extension to Kalyan took place on May 1, 1854.
The railway line from Kalyan to Khopoli was opened on May 12, 1856. Itwas further
extended to Poona on June 14, 1858 when thetraffic was opened for public use. In the
eastern partof India, the firstpassenger train steamed out of Howrah station for Hooghly,
a distance of 24 miles, on August15, 1854. This marked the formation of the EastIndian
Railway.
This was followed by the emergence for the Central Bengal Railway Company. These small
beginnings multiplied and by 1880, theIRsystemhad a route mileage of 9,000 miles in
India. The Northeastern Railway also developed rapidly. On October 19, 1875, thetrain
between Hathras Road and Mathura Cantonment was started. By the winter of 1880-81,
the Kanpur-Farukhabad linebecame operational and further east, the Dibrugarh-Dinjan
line became operational on August15, 1882. In South India, theMadras Railway Company
opened the firstrailway line between Veyasarpaudy and the Walajah Road (Arcot) on July
1, 1856. This 63-mile line was the firstsection, which eventually joined Madras and the
westcoast. On March 3, 1859, a length of 119 miles was laid fromAllahabad to Kanpur.
In 1862, therailway line between Amritsar and Attari was constructed on the Amritsar-
Lahoreroute. Some of the trains started by the British are still in existence. The Frontier

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Mail is one such train. It was started on September 1, 1928 as a replacement for the
Mumbai-Peshawar mail. Itbecame one of the fastesttrains in India at that time and its
reputation in London was very high. The Kalka Mail fromHowrah to Kalka was introduced
with the specific goal of facilitating the annualmigration of British officials, their families
and their retinue of servants and clerks from the imperial capital at Calcutta to the summer
capital in Shimla. FromKalka, there was the remarkabletoy train serviceto Shimla. Plans
for this narrow-gaugetrain had started as early as 1847, butit was at the intervention of
the Viceroy, Lord Curzon, thatwork actually began. Hence this train service was also
known as the Viceroy's Toy Train. In order to preventany head-on collisions on the single-
track sections of this railway service, the Neals Token Systemhas been used ever since the
train was inaugurated. The train guards exchangepouches containing small brass discs
with staff on the stations en route. The train driver then puts these discs into special
machines, which alert the signals ahead of their approach. The Darjeeling toy trains, the
Matheran toy train fromNeral to Matheran, the Nilgiri Blue Mountain Railway areother
engineering marvels running on routes designed and built by the British. Trains like the
Deccan Queen fromBombay to Secunderabad and the Grand Trunk Express fromDelhi to
Madras are someother prominent trains initiated by the British. With the advancement in
the railway system, electrifying railway lines began side by side, and it was in 1925, that
the firstelectric train ran over a distance of 16 kmfromVictoria Terminus to Kurala.
1.4 The needfor a Railway Network
The British rule in India was governed by three principal considerations to expand the IR
system. Thesewere the commercialadvantages, thepolitical aspect and even more
importantly, the inexorable imperialdefense of India against the possible military attacks
from certain powerfulcountries showing signsof extending their orbit of influence into
Central Asia.
1.5 Electric LocoShed, Tughlakabad
The Electric Loco Shed was setup in 1988 by Railway Electrification Organization (8910 sq
mtrs) and comes under the TRS section of Indian Railways. The main purposeof the shed is
to maintain the Electric Locomotive of the Models WAM 4, WAG 5, WAG7, WAP7, and
WAG9.
PresentLoco holding is around 195+. The WAG 9 & WAP 7 are the 3 phaseloco where as
WAM 4, WAG 5 & WAG 7 are the conventionaltype of loco. The main difference between
the conventionaland the three phaseloco is that the three phaseloco requires the three
phaseinduction motor and the conventional loco requires the DC Series motor. WAG 9

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model Loco is the latest model of the loco with the systemof regenerative braking and also
it uses various power electronics applications in it.
Specificationof the Loco’s in Loco Shed:
(i) WAM 4:
Manufacturers: CLW
TractionMotors: AlstomTAO 659 A1 (575kW, 750V). Six motors, axle-hung, nose-
suspended, force-ventilated.
Gear Ratio: 15:62 originally (and still for WAM-4 2S3P), now many variations, 21:58being
common for WAM-4 6P locos.
Transformer: Heil BOT 3460 A, 22.5kV /3460kVA.
Rectifiers: Two silicon rectifier cells, 1270V /1000A each cubicle.
Pantographs: Two Faiveley AM-12.
Axle load: 18.8t
Bogies: Alco asymmetric trimount (Co-Co), sameas with WDM-2, WDS-6, etc.
Hauling capacity: 2010t
Current Ratings: (WAM-4 6P) 1100A/10min, 750A continuous
Figure 1: WAM 4
(ii) WAG 5:
TractionMotors: AlstomTAO 659 (575kW, 750V, 1070rpm) or TAO 656; or Hitachi HS
15250A, Axle-hung, nose-suspended. Sixmotors.
Gear Ratio: 62:16 or 62:15 with Alstom motors, some64:18 (Hitachimotors), many now
58:21 for mixed use.

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Transformer: BHEL, type HETT-3900. 3900kVA,22.5kV,182A. 32 taps.
Rectifiers: Silicon rectifiers (two) using 64 S-18FN-350diodes each fromHind Rectifier.
2700A /1050V per cubicle.
Bogies: Co-Co castbogies (Alco asymmetric trimount -- shared with WDM-2, WAM-4).
Axle load: 20t
Max. Haulage: 2375t
Pantographs: Two Faiveley AM-12
Current Ratings: 1100A/10min, 750A continuous
Figure 2: WAG 5
(iii) WAG 7:
TractionMotors: Hitachi HS15250-G (thicker wiregauge, better insulation);Motors built by
CLW and BHEL.
Gear Ratio: 65:18 (65:16?)
Transformer: CCL India, typeCGTT-5400, 5400kVA, 32 taps.
Rectifiers: Two silicon rectifiers, cell type S18FN350(fromHind Rectifier), 64 per bridge,
2700A /1050V per cubicle.
Axle load: 20.5t
Bogies: Alco High-Adhesion bogies, fabricated bogie frameassembly, with unidirectional
mounting of traction motors, primary and secondary suspension.
Hauling Capacity: 3010t
Pantographs: Two Stone India (Calcutta) type AN-12.
Current Ratings: 1350A/2min, 1200A/10min, 960A/hr, 900A continuous

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Figure 3: WAG 7
(iv) WAP 7:
Manufacturers: CLW
TractionMotors: 6FRA 6068 3-phasesquirrel-cageinduction motors (850kW, 2180V,
1283/2484 rpm, 270/310A. Weight2100kg, forced-air ventilation, axle-hung, nose-
suspended. Torque6330/7140Nm. 95%efficiency.)
Gear Ratio: 72:20
Axle load: 20.5t
Wheel diameter: 1092mmnew, 1016mmworn
Bogies: Co-Co, ABB bogies; bogie wheel base1850mm+ 1850mm
Transformer: 7500 kVA
Body width: 3152mmn
Cab length: 2434mm
Pantograph lockeddown height: 4525mm
Figure 4: WAP 7

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(v) WAG 9:
Manufacturers: ABB, CLW
TractionMotors: ABB's 6FRA6068 (850kW, 2180V, 1283/2484 rpm, 270/310A. Weight
2100kg) Axle-hung, nose-suspended.
Gear Ratio: 77:15 / 64:18
Transformer: ABB's LOT 6500, 4x1450kVA.
Power Drive: Power convertor fromABB, type UW-2423-2810with SG 3000G X H24 GTO
thyristors (D 921S45Tdiodes), 14 thyristors per unit (two units). Line convertor rated at 2
x 1269V @ 50Hz, with DClink voltage of 2800V. Motor/driveconvertor rated at 2180V
phaseto phase, 971A outputcurrent per phase, motor frequency from0 to 132Hz.
Hauling capacity: 4250t
Bogies: Co-Co, ABB bogies; bogie wheel base1850mm+ 1850mm
Wheel base: 15700mm
Axle load: 20.5t
Unsprung mass per axle: 3.984t
Lengthover buffers: 20562mm
Lengthover headstocks: 19280mm
Body width: 3152mmn
Cab length: 2434mm
Pantographs: Two Secheron ES10 1Q3-2500.
Pantograph lockeddown height: 4525mm
Figure 5: WAG 9
The work of the various locos is spread into 10 sections whosefunctions and components
are described under the upcoming sections.

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CHAPTER 2: OVERVIEW OF SECTIONS
1.1 SECTIONM1- CONTACTORSECTION
A contactor is a special type of switch used for closing and opening of high voltage
circuits and it can be remote controlled fromdriver’s desk whenever necessary.
TYPES OF CONTACTORS: There are four types of contactors used on locos.
a) Electromagnetic Contactors
b) Electro pneumatic Contactors
c) Drumtype Contactors
d) Cam Contactors
1.2 SECTIONM2- RELAY SECTION
Relay is a sensitive device provided to ensure proper functioning of an apparatus either
in the electrical circuit or pressure/fluid circuitto safe guard the apparatus during any
abnormalities.
PressureRelays: - RGCP, QPDJ, P1, P2, RGAF, SWC, RGEB1, RGEB2
Magnet Valves: VEPT 1&2, VEF, VEAD, ULV 1,2&3, IP, VESA1,2,3,4,
Special type of Magnet valves: - MV4, D1 pilot (VEF- E+M combined)
1.3 SECTIONM3- TRACTIONMOTORSECTION
A traction motor is an electric motor used for propulsion of a vehicle, such as an
electric locomotive or electric roadway vehicle. And this section maintains the working
of the traction motor.
1.4 SECTIONM4- BOGIESECTION
Initially electric locomotives were imported. But at present Chittaranjan Locomotive
Works (CLW) is manufacturing electric locomotives of all types. The manufacturing
capacity of CLW is 120 locos per year. There are three types of bogies generally used in
Electric Locos.
a) B-B Type
b) Bo-Bo Type
c) Co-Co Type
1.5 SECTIONM5- COMPRESSORAND EXHAUSTERSECTION
The purposeof the compressors is to build up compressed air required for various
purposes in the locomotive. The Exhausters MPV 1 & 2 is provided for creating and
maintaining Vacuum on train pipe. These motors starts working through theremote
control switch BLPV. And hence Section M5 helps in maintaining the Compressor and
Exhausters used in the locomotive.

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1.6 SECTIONM5- PANTOGRAPH SECTION
Itis a collapsible framework mounted on loco roof. Pantograph is mounted on four
base insulators. This frameis made of severalmetallic tubes and springs.
1.7 SECTIONM6- MOH(Major Overall) SECTION
This section opens the engine internal parts and supplies it to its respectivesection for
the maintenance and repairing of the various equipments used in the Locomotive.
1.8 SECTIONM7- PNEUMATICSECTION
This section deals mainly in the mechanical section such as braking and maintenance of
the compressed air in the pipes.
1.9 SECTIONM8- POWERSECTION
This section is main as in terms of electrical as it deals with the power equipments such
as VCB (vacuumcircuit breaker), tap changer, transformer, BDV (breakdown voltage
analysis), DGA (dissolvegas analysis) etc.
1.10 SECTIONM9- ELECTRONICS SECTION
This section is the maintenance of power electronics which is the latest technology
being used in the latest locomotive such as SL (smoothening reactors), CHBA (battery
charger), SIV (static converter), ACdamping panel etc.
1.11 SECTIONM10- WHEEL SECTION
This section mainly deals with the repairing of the wheels and greasing of it. Generally
in all locomotives solid wheel is used due to the needs of increase traffic, higher speed,
steeper gradients all of which demand stronger braking.

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CHAPTER 3: CLASSIFICATION OF LOCOMOTIVES
The classification of Electric locomotives is based on the type of serviceused for. The alphabet
stands for:
W >>> Broad Gauge
Y >>> Meter Gauge
Z >>> Narrow Gauge
A >>> AC locos
M >>> Mixed Traffic (Goods or passenger Services)
G >>> Goods Service
P >>> Passenger Service
C >>> DC locos
D>>> Diesel locos
CA >>> AC/DC locos
U>>> Multiple units(EMU, DMU)
And the number after it represents the model number of that locomotive.
EXAMPLE: If we wantto name a locomotive which is used in broad gauge with AC supply and
for goods and model 7. How would it be written?
ANSWER:WAG 7
EXAMPLE: If we wantto name a locomotive which is used in meter gauge with diesel loco and
used for passengers and model 2. How would it be written?
ANSWER:YDP 2

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CHAPTER 4: CONTACTOR SECTION
A contactor is a special type of switch used for closing and opening of high voltage circuits and
it can be remote controlled from driver’s desk whenever necessary.
TYPES OF CONTACTORS: There are four types of contactors used on locos.
a) Electromagnetic Contactors
b) Electro pneumatic Contactors
c) Drumtype Contactors
d) Cam Contactors
4.1 ELECTROMAGNETIC CONTACTORS: In this typeof contractors and electromagnet is used
for operating the driving mechanism. When the switch BLCP is closed the contactor coil gets
magnetized. The armature attached to the actuating rod is attracted by electromagnet. So the
armaturecomes in contact with the magnet. Due to this action the actuating rod is operated
and the mobile jaw of the contactor moves upwards and comes in contact with fixed jaw. Now
high tension circuit is closed and the receiver starts functioning. When the switch is opened
the electromagnet gets reenergized, the armatureis pulled back to its original position by the
action of return spring. Due to this action the jaw of the contactor is moved downwards so
that the HT circuit gets opened and the receiver stops working. A flexible shunt is provided
with mobile jaw for easy movement which is in the shape of pigtail. A blow out coil is provided
for extinguishing the arc produced between the fixed and mobile jaws at the time of opening
of the contactor. Ex. C 101, C105, C 106, C107, C 118 etc.
Figure 6: Electromagnetic Contactor

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4.2 ELECTRO PNEUMATIC CONTACTORS: In this typeof contactor the driving mechanism is
operated by the servomotor. Theair pressurefor the servomotor is admitted by operating the
electro valve, which is operated by an electromagnet.
When the switch is closed the electromagnet gets energized and attracts the armaturewhen
the armaturemoves upwards thevalve closes the passagebetween B and A chambers and
opens the passagebetween C and B chambers. Dueto this action the air from C chamber
enters to B chamber of servomotor. Through Bchamber, the air pressureoperates the piston
towards upwards, so thatthe actuating rod is moved upwards and makes the mobile contact
to come in contact with fixed contact. So that the contactor is closed and motor starts
functioning. When the switch is opened the electromagnet gets de-energized and the valves
are pulled back to their original position by the action of return spring. Dueto this action the
valves closes the passagebetween C and B chambers and opens the passagebetween B and A
chambers, the exhaust air fromB chamber of servomotor gets exhausted through A chamber
exhaust hole, hence the return spring pushes down the servomotor piston so that the
actuating rod is operated which in turn pulls back the mobile jaw and the contactor gets
opened. Example Line contactors and shunting contactors.
Figure 7: Electro Pneumatic Contactor
4.3 DRUM CONTACTORS: In this typeof contactor an insulated drumis used for closing and
opening the circuit. The drumis rotated by two pistons of servomotor and the air for the
servomotor is admitted by the action of two electro valves. Two copper segments are fixed on

22. 22
the drumwith sockethead screws separately which will act as mobile jaw and closes the
circuit.
Whenever the drumis rotated the copper segments are connected with the HT circuit through
fixed contacts (finger contacts). On one sidethe segment ‘a’ is connected with finger contact
‘F’. Due to this action the circuit is closed and currentwill flow in one direction (forward).
When the drum is rotated on the opposite direction the segment‘a’ leaves the contact with
finger contact ‘F’ and segment ‘b’ will come in contact with finger contact ‘R’. Now the circuit
is closed in reversedirection and the current flows to the TM field in the reversedirection.
Blow out coils are not provided on drumcontactors since they are operated under no load
conditions. Example Reverser J1 and J2.
Reverser J 1 is for changing the direction of flow of currentfor TMs 1, 4 and 2 and reverser J 2
is for changing the direction of flow of current for TMs 3, 6 and 5. The position of the manual
operating handle should be in upward direction when cab – 1 is leading and it should be in
downward direction when cab – 2 is leading.
4.4 CAM CONTACTORS: In this typeof contactor one or more switches can be operated with
the help of cams fixed on a shaftand operated through pinion and gear. The pinion and gear is
operated with the help of SMGRservomotor. A cam is around disc made with an insulating
material. Required number of grooves aremade on the circumferenceof the cam. A roller is
attached to the mobile jaw and placed on the cams. When the shaftis rotated the cam also
rotates. During the movement of the cams the rollers come out fromthe grooves and make
contact with fixed jaw and close the circuit. When the roller moves inside the groovethe
mobile jaw leaves the contact with the fixed jaw to make the circuit open. The opening and
closing of the mobile jaw will depend up on the number of grooves arranged on the cams
according to the sequence of our requirement. Example CGR – 1, CGR – 2, CGR – 3.
Figure 8: CAM Contactor

23. 23
4.5 PRINCIPLEOF CONTACTORS:Theswitches in the loco are remote controlled from Driver’s
cab. These switches which are controlled froma distance are called contactor. A contactor has
three main parts:
1. The contact position which consistof fixed jaw, mobile jaw, flexible shunt, Insulator and
axle.
2. The driving mechanismwhich acts as a movable jaw.
3. The remote control arrangementis worked by 110 V battery, which energizes the driving
mechanism.
S.No Description IdealValue InstrumentUsed
1. Pick up voltage 57-68V Voltmeter
2. Drop out voltage 10-20V Voltmeter
3. Distance between the contactors 40mm(min) Scale
4. Width of fixed contact 3mm Scale
5. Width of moving contact 3mm Scale
6. Distance between the fixed and moving contact 8.5±1mm Go-no-Go gauge
7. Resistance of coil 550+8% Ω Multimeter
8. Crushing distance 3.8-4.8 mm Go-no-Go gauge
9. Contact pressure 700-900 gm Gramgauge
10. Distance between fixed contact and blow out
coil support
53±0.5 mm Scale
11. Insulation resistancebetween the connection Not less than 1
MΩ
Meager
Table 2: EM contactor testing parameters and instruction
4.6 TAP CHANGER: Theoutput voltage of a transformer varies according to the turn’s ratio of
the primary and the secondary windings of the transformer. Itcan be appreciated that at any
point of the primary or the secondary winding the voltage is different fromany other point on
the samewinding becausethese points are at different ratios with respectto the other
winding. Hence each and every tap broughtout fromthe winding gives a different voltage.
Broadly tap-changers can be divided into two categories-namely off-load and on-load.
Off-load tap-changerscannotbe operated while currentis flowing in the circuit. Off-load tap-
changers are used mainly for non-critical applications wherea momentary interruption in the
currentcan be tolerated. Hence, such tap-changers haveno usein traction duty.
In traction only on-load tap-changers(OLTC) areused. They are capable of changing the taps
rapidly without interrupting the flow of current.

24. 24
a) WORKING PRINCIPLE: The tap changer is directly built on to the transformer. The
tappings of the auto transformer winding arebroughtout and arranged in circular
fashion in two rows on an insulated contact plate. There are two rows of contact
segments which are arranged on outer and inner circle of the contact plate. An arm
which is known as selector arm driven by a shaftat the centre of contact plate. Two
rollers are fixed at the edge of the selector arm. These rollers make connection between
respective segments (even and odd numbered notches) and outer or inner rings. These
rings are provided in front of the tap changer casing is driven by an air servomotor
known as SMGR. The design of the air servomotor is such that once the selector arm
begins it movement it can only be stopped at the required tap (not in between two
taps). The connection between the inner and outer rings to the transformer is being
established by means of CGR contactors.
b) OPERATION:Theselector arm is actuated by driving shaftthrough an intermediate
gearing comprising of driving wheel, lateral gear pinion and stepping wheel. This driving
shaftalso operates CGR cam shaft in sequence with the operation of contact rollers. For
opening and closing sequence of CGR contacts are as follows:
CGR 1 CGR 2 CGR 3
Half Notch (1/2 notch) Close Close Close
Odd Notch (1,3,5……..31) Close Open Open
Even Notch (2,4,6……..32) Open Close Close
Before the moving contact rollers leaves the zero tap contact segment it touches the
firsttap segment. During this CGR2 contactor closes and inserts the diverter resistance
RGR in between the tapings of winding. Thus the winding between tap zero and tap 1 is
coming in series with the resistanceRGR, which limits the circulating shortcircuit
currentdue to the emf difference between tap 1 and tap zero (No of turns of auto
transformer). When the contactor arm further moves fully on to tap 1 the inner contact
roller breaks contact with zero tap. Mean while CGR 2 contacts open and cut off the
resistanceRGR from circuit. Likewise when selector arm moves from1sttap to 2nd tap
the contact roller (outer) will continue to make connection with tap 1 segment and the
inner contact roller establishes the contact between inner segment to inner ring (this is
due to over lapping of contact segment) at the same time CGR 1,2 are closed again to
insert the resistanceRGR in between the shortcircuited winding. (Now the current
flows fromthe contact ring outer to). When the selector arm further moves, the outer
roller leaves contact with tap 1 segment and breaks the contact. At the same time CGR 1
gets opened and CGR 2 and 3 gets closed. This again cuts off the resistanceRGR from

25. 25
the circuit. The opening and closing of CGR contacts is carried out by a cam shaft which
is driven by the main shaft through gear mechanism. This ensures a perfect relationship
between the movement of selector armand the operation of CGR contact. A high
resistanceRPGR serves as the connection between equal potentials, which ensures that
the branches of circuit being interrupted at a given potential.
c) WORKING PRINCIPLE: When ever any controlcommand is given to the solenoid of UP or
DOWNvalvethe respective valvegets energized and transmits pressurepulses to the
control block cylinder. This causes the lever armwith toothed segmentto rotate about
the pivoteither towards the right or left with respect to the energizing of progression or
regression coil. The toothed segment engages with the pinion which carries the axes of
planetarian wheel the annulus is stationary. Movementof the planet wheel causes the
cam shaftto rotate in one direction or the other direction through 75˚(known as lead
angle). This induces the displacement of cam shaft relative to the crankshaftposition as
long as the control command persists. Sincethe cam shaftis displaced by 75˚ the
operating piston is actuated and drives the crank shaftthrough half rotation. The other
half rotation is completed by kinetic energy stored in the flywheel mechanically such
that the motor can complete one tap change operation entirely. The crank shaftin turn
rotates the com plates through a spur gear and an intermediate wheel. The cam Plate is
operating the auxiliary switches of the control circuit. There are four cylinders, two for
notching up and two for notching down. For notching up cylinder no 1 is vented and for
notching down cylinder no 3 is vented and cylinder no 4 is pressurized. Venting and
pressuring of cylinder is decided by the piston of the 3-way valvewhich is operated by
the cam shaftthrough valvepush rod. There is a notching lever with spring arrangement
provided in the crankshaftto hold the shaftat the tapings when no air pressureis
available. This also ensures that the crankshaftstops in the correctposition. A
mechanical interlock called limit stop is coupled with the crankshaftwhich prevents the
over running the limit position i.e. beyond zero or 32 notches when the mechanismis
operated by hand.

26. 26
CHAPTER 5: RELAY SECTION
Relay is a sensitive device provided to ensure proper functioning of an apparatus either in the
electrical circuit or pressure/fluid circuitto safeguard the apparatus during any abnormalities.
Mechanical Relays Electrical Relays
Air Flow Oil
Flow
Voltage
Relay
Current
Relay
Earth Fault
Relay
Signaling
Relay
Functional
Relay
QVSI 1,2
QVSL 1,2
QVM1,2
QVRH
QVRF
QPH Q20
Q30
QCVAR
QLM
QLA
QRSI 1,2
QD 1,2
QE
QF 1,2
QOP 1,2
QOA
QV60
QV61
QV62
QV63
QV64
QVLSOL
Q44, Q45, Q46,
Q47, Q48, Q49,
Q50, Q51, Q52,
Q118, Q119,
Q100, QTD105,
QTD106, PR1,
PR2, QFL,
QWC, QPV
Table 3: Relay's used in LOCO
PressureRelays: - RGCP, QPDJ, P1, P2, RGAF, SWC, RGEB1, RGEB2
Magnet Valves: VEPT 1&2, VEF, VEAD, ULV 1,2&3, IP, VESA1,2,3,4,
Special type of Magnet valves: - MV4, D1 pilot (VEF- E+M combined)
QLM:The relay QLMis fed by means of the high voltage current transformer TFILM, which
causes high voltage circuit breaker DJ to trip out, if the currenttaken in by the main
transformer exceeds the setting value of the relay.
QOP: Voltage operated relay for earth faults in main traction circuit and DJ.
DJ: Opens under the control of various protection devices. From'disjoncteur', French term for
circuit breaker.
QOA:Earth fault protection of auxiliaries and opens the DJ.
QRSI 1, 2: The relays QRSI 1-2 arefed by means of the rectifier currenttransformer RSILM1
and 2 (4000/5A) which causethe high voltage circuit breaker to trip, if the currenttaken in by
the rectifiers exceeds the setting value of the relays (3600 A).
QD 1, 2: Wheel slip relays are of differential type. When the currentdifference is 125 A in
between traction motors 2 and 3 and traction motors 4 and 5, the relay operates. In case of
wheel slipping, it feeds relay Q-48, thereby energizing sanding electro valves VESA and sand is
applied to corresponding wheels Relay Q-51 is also energizes causing regression of tap changer
till the slipping stops.
QOP 1, 2: In caseof failure of insulation of traction power circuit to earth, the battery supply
available across the allows to pick up the relay through the earth fault path and in turn opens
the HV circuit breaker DJ. The switch HQOP 1-2 makes it possible to isolate the relay QOP 1 or
2 and inserts a resistanceRQOP in the earthed path in order to limit the fault current.
Otherwiseit will not be possible to switch on again the circuit breaker DJ to clear the section
and bring the locomotive to the shed.

27. 27
Q 20:Relay Q-20 with series resistanceRQ-20 is connected across rectifier output and causes
buzzer SON1-2 to work. Therelay picks up if, TM voltage exceeds 854 V. When voltage falls to
740 V, the Q20 relay resets and buzzer stops working. Only in YAM-1 - Sounds a buzzer if
voltage for traction motors is exceeded
Q 30:The relay Q-30 drops out if the single-phaseauxiliary winding voltage drops below 215
volts. Its contacts switch off relay Q-44, thereby tripping DJ. Relay Q-30 is switched on directly
through the contacts of the relays Q-45 and remains in the circuit with series resistor RQ-30
after the relay Q-45 opens/drops. Opens DJ if catenary loses power.
QCVAR:Relay QCVAR has been put across ‘W’ phaseand neutral of ARNO to ensurethat the
ARNO starting resistanceis 118 is disconnected fromthe circuit when generated face voltage
is in between 150 to 160 V AC. This cuts out ARNO starting contactor C118. The relay picks up
at 155-160 volts AC.
QV 61: This relay is provided across battery charger CHBA and indicates the working of the
charger. This relay is English Electric make picks up below 68V DC.
QRS: Relay QRS is energized when the loco is in running condition and de energized when the
brakeis applied. This relay operates through its N/C contacts and regresses thetap changer.
QE: The relay QE is fed by means of the excitation currenttransformer which causes the
braking excitation contactor C145 to trip out, if the currenttaken by the excitation winding of
the motors exceed the setting value of the relay (900 A).
QF 1,2: The relays QF 1-2 areconnected through the shunts SHF 1-2, which causethe braking
excitation contactors C-145 to trip out, if the current in the braking resistance RF-1 and 2
exceeds the setting value of the relays (900 A).
QPH: Trips DJ if oil flow in main transformer fails.
QVM 1, 2: Detects failure of traction motor blowers and trips DJ.
Q 52:Trips DJ if incorrect notching occurs in tap changer.
Q118: A time delay which opens the DJ in the event of auxiliary failure.
QVRH: Relay to check the working of MVRH (Motor blower to cool the Transformer oil).

28. 28
CHAPTER 6: TRACTION MOTOR SECTION
Motor is machine which converts the electrical energy into mechanical energy. DCmotor
works on the principle of attraction and repulsion.
6.1 WORKING:When the switch ‘H’ is closed the inductor and armatureare energized. The
inductors posses somepolarity. The armature is get before the inductors in such a way so that
to maintain equal polarity to the inductor on either sides. Since like poles repel each other,
now the armatureand inductor will try to be away fromeach other. The inductors are
stationary. So they will not move. But armatureis movable, so it will move and starts rotating.
At the same time the other inductor will attract the unlike pole of the armaturetowards it,
there by the rotation of the armatureincreases. Now, when the armaturerotates the polarity
of the armature is charged by the commutator in such a way so that it keeps equal polarity in
frontof the other inductor at the time of the arrival towards it. So, again the reputation and
attraction takes place and rotation of the armature continues. The commutator continues to
change the polarity of armaturepoles at appropriate time, there by the motor rotates until the
switch H is opened. The motor provided with the tow inductors is known as two pole motor. If
it is of four inductors then it is four pole motor and so on.
6.2 TYPES OF DC MOTORS:
1. Separately excited motor
2. Series excited motor.
3. Shunt excited motor.
Out AC locos are provided with DC series excited motors. In this type of motor armatureand
inductors are connected in series to a single DC source. So it is called as series excited motor.
They are mostuseful for traction purpose.
6.3 ADVANTAGEOF DC SERIES EXCITED MOTOR:
1. Starting torque of is very high (torque in the forcethat tends to producea turning effect on
the shaft).
2. Reversal of the rotation of the motor is very easy.
3. Variable speed is possiblethan by any other type of DCmotors.
Reversing the direction of the rotation of a motor:
For reversing the direction of rotation of motor the direction of the flow of the current should
be changed either in the field or in the armaturecoil. But, if the direction of flow of currentis

29. 29
charged in the both field as well as armature, the rotation of the motor will not change. On AC
locos for changing the direction of rotation of the traction motor the direction of flow of
currentis changed in the fields (inductors) with the help of reversers. This in turn will reverse
the direction of the locomotive.
Note: The reversalof the rotation should be done after stopping the motor (i.e. locomotive).
Otherwiseserious damages will be caused.
6.4 TRACTION MOTORS: In WAG-5 loco, TM-1, 2, 3 are provided in bogie-1 and TM-4, 5, 6 are
provided in bogie-2. These motors areaxle-hung, nosesuspended type. There are two types of
traction motors supplied by CLW i.e., TAO 659 & Hitachi.
Greaselubricated roller bearings are used for the armature& for suspension in Hitachi motors.
In TAO 659 motors, Roller bearings for the armature& white metal plain sleeve bearings for
suspension areused.
Special provision has been made in design of the motors to ensurethat locomotive can be
operated satisfactorily on flooded track, to a maximum flood level of 20 cm above rail level.
MAKE CLW CLW
Type HS 15250 A TAO 659
Continuous output 630 KW 585 KW
Voltage 750 V 750 V
Starting current 1350 A 1100 A
Current(continuous) 900 A 840 A
Speed 895 rev/min 1060 rev/min
Maximum servicespeed 2150 rev/min 2500 rev/min
Insulation CLASS C CLASS H
Number of poles Main 6,
Interpoles 6
Main 6,
Interpole6
Table 4: Traction Motor details
There are total 6 traction motors used in the WAG 9/ WAP 7 loco. TM 1-2-3 aremounted in
bogie 1 and fed fromtraction converter 1 whereas TM 4-5-6 aremounted in bogie 2 and fed
fromthe traction converter 2. In case of WAP 5 there are 4 traction motors in which traction
converter 1 fed to TM 1-2 where as traction converter 2 fed to TM 3-4.
Unlike conventional WAG 5/7 individual TM cannot be isolated in this loco only group isolation
is possible. For isolation of TM group one rotating switch number 154 is provided in SB-1, its
normal position is ‘NORM’.

30. 30
In WAP 7 and WAG 9 the traction motor is forced air cooled and intended for transverse
installation in a 3 motor bogie. Traction motor is suspended on axel, by axel cap at one end
and on link at another end.
Figure 9: Traction Motor mounted on Wheel

31. 31
CHAPTER 7: BOGIE SECTION
Bogies in locomotive are provided to permit long length of locomotive body to negotiate the
curves. A small length of bogie is desirable. The length of bogies is decided by the distance
between the centre of extreme wheels of bogie is known as bogie wheelbase. Bogie
wheelbase shallbe well proportioned to permit the bogie negotiating the curveand jerking.
The bogie has two a more bogies on which the body is mounted. The distance between the
centers of extreme wheels is known as the total wheelbase.
7.1 BOGIES CLASSIFICATION: Bogies areclassified on
1) Number of axles
2) Type of axle drive
The type of axle drive and number of axles in the bogie is also called the wheel arrangement.
Wheel arrangements areclassified as B, BO and CO.
B: Two axles, axles are mechanically coupled
BO: Two axles, axles are independently driven
CO: Three axles, axles are independently driven
Locomotive always havetwo or more bodies. So the wheel arrangementof the locomotive is
designed as B-B, BO-BO and CO-CO. Initially electric locomotives were imported. But at
present Chittaranjan LocomotiveWorks (CLW) is manufacturing electric locomotives of all
types. The manufacturing capacity of CLW is 120 locos per year. There are three types of
bogies generally used in Electric Locos.
a) B – B Type: - These types of bogies are available in WAG-1 and WAG-4 locomotives. In this
type one traction motor has to drive two axles in a bogie through a gear system. Each loco will
have two bogies i.e. two TMs per loco. This type is also named as monomotor bogies.
b) BO – BO Type: - Each bogie is having two axles driven by TMs independently i.e. each loco
will have 4 TMs. These types of bogies are available in WAM-1 and 2 locos. (At presentthese
types of locos arenot available in SCR).
c) CO – CO Type: - This bogie is having three axles in each bogie driven by three independent
TMs. These bogies are available in WAM-4, WAG-5A, WAP-1, WCG-2, WCM-5, WCAM-1 types
of locos. Each loco is having two bogies i.e. total six traction motors.

32. 32
Wheel Arrangement Locomotive Type
B-B WAG1, WAG2, WAG4, WAM1
BO-BO WAM1, WAM2, WAM3, WAP5
CO-CO WAM4, WAG5, WAG6C, WCAM1, WAP1-3
BO-BO-BO-BO WAG 6A, WAG 6B
Table 5: Bogie arrangement
7.2 BOGIECOMPONENTS: Thebogie of a locomotive is an assembly of following components.
1. Bogies Frame
2. Wheels
3. Axles
4. Springs
5. Axle Boxes
6. Supports for Traction Motors
7. Supports for BrakeRigging & BrakeCylinder
8. Friction Dampers / Snubbers.
7.3 CO-CO TRIMOUNTBOGIE: Majority of the locomotives in Indian Railways is provided with
this type of bogies. The bogie consists of single piece cast steel bogie frame carrying the center
pivot in the cross member located towards the end of the locomotive. Center pivot carries
60% of vertical load; it receives and transmits Tractiveand braking forces. The side bearers
take the other 40% of vertical load. The side bearers do not receive or transmit Tractiveand
braking forces. The frameis supported by four sets of double equalizers extending from the
end axles to the center axle. Full equalization is obtaining by suitable positioning the springs
and controlling their working height. The weight of locomotive body is transferred to the bogie
at center pivot and two side bearers to forma three point supports. This type of bogie is
known as Tri-mountBogie.
Suspensions: - Suspensions near bogieare provided to reduce the vibration. The vibrations are
picked up by the wheel, which is mounted on railway track which if self is shaking up and down
due to irregularities in the surface. The suspension systemalso balances the vertical loads
between the wheels and provides passenger comfortby reducing vibrations in the vehicle
body. The suspension between the axle and the bogie frame constitutes the primary
suspension. Thesuspension between the bogies frame and vehicles body is called secondary
suspension. Suspension, consisting of four groups of helical coil springs. Each group of springs
consists of two nests of one outer and one inner coil. To prevent uncontrolled bouncing effect
of locomotive body supported on helical coil springs damper is provided as a resisting force.

33. 33
Types of dampers are: -
1. Friction Damper
2. Hydraulic Damper
In Tri-mountbogie friction damper or snubber is provided on four of the inner coils of each
bogie.
7.4 TETRA MOUNTHIGH ADHESION BOGIE: This bogie is provided for WAG7 locomotives.
Introduction: - With increasing demand of heavy freighttraffic on Indian Railways, a new high
adhesion bogie has been developed by RDSO for high horsepower freight locomotive to
achieve higher Tractive effortof 42 tones at start. The bogies exhibit better adhesion
characteristics with reduced weight transfer.
GeneralArrangementof Bogie: - This a three-axle type bolster less bogies with two-stage
suspension, floating pivotand unidirectional arrangementof axle hung nosesuspended
traction motors. Bogies frameis of straightand fabricated box type construction with three
transoms to carry nosesuspension.
The locomotive body weight is supported on bogie frame through four rubber side bearers
directly mounted on bogie side beams. Shims have been provided below outer side bearers to
distribute load on side bearers in a 60%: 40% ratio, 60% of load being supported on side
bearers adjacent to centre pivot and 40% of the load at remaining two side bearers. Center
pivot does not take any vertical load and is used only formtransfer of traction and braking
forces. The bogie frame in turn is supported on axles through helical coil springs mounted on
equalizer beams. The equalizing mechanism consists of equalizers hung directly on end axle
boxes and supported on middle axle box through a link and compensating beam arrangement.
The equalizing mechanism enables achievement of equal axle loads on uneven track and
reduces weight transfer at start.
Suspension Arrangement: - The bogies has two-stagesuspension with helical coil springs
between axle box and bogies frame in primary stage and side bearers (rubber sand which)
between bogies frameand locomotive body in secondary stage. The lateral stiffness of rubber
springs is utilized to provideto provide lateral guidance at the secondary stage. Four vertical
hydraulic dampers, one with each nest of primary springs & Two lateral hydraulic dampers are
provided in secondary stageto supplementthe damping provided by side bearers both in
lateral and rotational modes which prevents nosing at high speed. Two lateral rubber stops are
provided on each bogie on either side of the middle axle to limit lateral movements. Vertical

34. 34
stops are provided on bogie frameto limit vertical movement between axle boxes and bogie
frame.
Roller Bearing Axle Boxes: - Movable axle journalboxes are mounted in pedestals or horns,
fabricated integral with the frame. Lateral play for negotiating curves and turnouts is obtained
by the movement of axle boxes in horns. End axle boxes are provided with rubber thrustpads
to cushion lateral thrust, while 10 mm lateral plate is provided on middle axle boxes.
7.5 BOGIECOMPONENTS ARRANGEMENT:
Figure 10: Bogie components
Bogie Frame: Can be of steel plate or cast steel. In this case, it is a modern design of welded
steel box formatwhere the structureis formed into hollow sections of the required shape.
Bogie Transom: Transversestructuralmember of bogie frame(usually two off) which also
supports thecar body guidance parts and the traction motors.
Brake Cylinder: An air brakecylinder is provided for each wheel. A cylinder can operate tread
or disc brakes. Somedesigns incorporate parking brakes as well. Some bogies have two
brakecylinders per wheel for heavy duty braking requirements. Each wheel is provided with a
brakedisc on each side and a brakepad actuated by the brake cylinder. A pair of pads is hung
fromthe bogie frame and activated by links attached to the piston in the brake cylinder.
When air is admitted into the brake cylinder, the internal piston moves these links and causes

35. 35
the brakepads to press againstthe discs. A brakehanger supportbracketcarries the brake
hangers, fromwhich the pads are hung.
Primary Suspension Coil: A steel coil spring, two of which are fitted to each axlebox in this
design. They carry the weight of the bogie frame and anything attached to it.
Motor Suspension Tube: Many motors are suspended between the transversemember of the
bogie frame called the transomand the axle. This motor is called "nosesuspended" becauseit
is hung between the suspension tubeand a single mounting on the bogie transomcalled the
nose.
Gearbox: This contains the pinion and gearwheel which connects the drive from the armature
to the axle.
Lifting Lug: Allows the bogie to be lifted by a crane without the need to tie chains or ropes
around the frame.
Motor: Normally, each axle has its own motor. It drives the axle through the gearbox. Some
designs, particularly on tramcars, usea motor to drive two axles
NeutralSection Switch Detector: In the UK, the overhead line is divided into sections with short
neutral sections separating them. Itis necessary to switch off the currenton the train while
the neutral section is crossed. A magnetic device mounted on the track marks the startand
finish of the neutral section. The device is detected by a box mounted on the leading bogie of
the train to informthe equipment when to switch off and on.
SecondarySuspension Air Bag: Rubber air suspension bags areprovided as the secondary
suspension systemfor most modern trains. The air is supplied fromthe train's compressed air
system.
Wheel Slide Protection System Lead to Axle box: Where a Wheel Slide Protection (WSP) system
is fitted; axle boxes are fitted with speed sensors. Theseare connected by means of a cable
attached to the WSP box cover on the axle end.
Loose Leads for Connection to Car body: The motor circuits are connected to the traction
equipment in the car or locomotive by flexible leads shown here.
Shock Absorber: To reducethe effects of vibration occurring as a resultof the wheel/rail
interface.

36. 36
Axle box Cover: Simple protection for the return currentbrush, if fitted, and the axle bearing
lubrication.

37. 37
CHAPTER 8: COMPRESSOR AND EXHAUSTER SECTION
8.1 INTRODUCTION:Auxiliary Motors (often referred to as compressor and exhauster in
LOCO) used in loco is 3 phaseAC Induction Motors. The motor are has 3 sets of stator coils
which are energized by 3 Ø AC supply and the rotor coils are fed by induction, and hence it is
called a 3 Ø Induction Motor.
TYPE OF
MOTOR
HP KW RPM RELAY POLE SWITCH BEARINGS CONTACTORS
MPH 4.3 3 2880 QPH 2 HPH 6305 --
MVSL 1,2 3.0 3 2960 QVSL 1,2 2 HVSL 1,2 6306 --
MVSI 1,2 3.0 2.2 2960 QVSI 1,2 2 HVSI 1,2 6306,6204 --
MVRH 30 22 1440 QVRH 4 HVRH 6313,6312 --
MVMT 1,2 35 26 2960 QVMT
1,2
2 HVMT
1,2
6313,6312 --
MCP 1,2,3 14.5 10.4 985 -- 6 HCP 6310 C101,102,103
MVRF DC -- -- 3000-
4000
QVRF -- -- 6409 --
MVRF A/C 30 22 -- QVRF 2 -- -- C108
MPV 1,2 -- -- 985 -- 6 HPV 1,2 6309 C111,112
MCPA (DC) 1.0 -- 1500 -- -- ZCPA 6306,6304 --
Table 6: Auxiliary motors in LOCO
8.2 ARNO CONVERTER: Thesingle phasesupply of 380 volts AC is fed direct to the ‘U’ and ‘V’
phases of the Arno converter. Since the Arno Converter is connected to single phase supply,
no starting torque is developed. For starting the ‘Arno’ a split phasestarting method has been
employed. The ‘W’ phase winding is connected to the supply phaseU through a starting
resistor R-118 and starting contactor C-118 for a shortduration to start the Arno. Thus
unbalanced three phasevoltage is impressed to each phasewinding of Arno Converter and the
starting torque is developed. The Arno Converter picks up speed within 5 seconds. After the
Arno has gained sufficientspeed, the phase ‘W’ is opened fromthe starting circuit by starting
contactor C-118. If the starting phasefails to open out within 5 seconds after Arno gained its
rated speed, there will be excessivevibration of the Arno and Overheating of the Arno starting
resistor. An interlock of relay ‘QCVAR’ opens C-118 coil circuit, to protect against overheating.
The neutral point’0’ of the Arno is connected to an earth fault relay QOA, which performs the
same function as the relay QOP, in power circuit. The relay QOA trips the circuit breaker (DJ) of
the locomotive in the event of an earth fault in the auxiliary circuit. The switch HQOA and
RQOA performthe same functions as the switch HQOP and resistor RQOP in the power circuit.

38. 38
In addition, the relay QOA is permanently shunted by a resistanceRPQOA.
The Arno converts the single phaseinput into 3-phaseoutputas 380V±22.5%.Theratio of
negative sequence voltage to positive sequence voltage is within 5%. The 3-phaseoutput of
the Arno converter is connected to the auxiliary motors.
RATINGS: - Make Jyothi
1-phaseinput 3-phaseinput
kVA 150 kVA 120
Voltage 380 V±22.5% Voltage 380 V±22.5%
Current 395 A Current 190 A
BLOWER MOTOR FOR SILICONRECTIFIER (MVSI 1&2): Each rectifier cubicle is provided with
one blower, which is driven by the motor MVSI. The motors of rectifier cubicle are controlled
by means of switch HVSI 1&2 which areprovided on RSI 1 & 2 blocks respectively. The cooling
of rectifier is monitored by the airflow relay QVSI 1&2. Theinterlock of QVSI 1 &2 are
connected in series with relay Q44. In the event of any MVSI 1 & 2 fails to work, respectiveair
flow relay QVSI does notpick up and its interlock opens on Q44 branch causing de-
energisation of Q44 in turn trips DJ. IncaseMVSI 1 & 2 are working normaland QVSI1 & 2
relays found defective, respective relay can be by-passed through HVSI 1&2 switches. These
are directly startmotors along with ARNO. This is an axial flow motor with 2.2 kW capacity.
Following are the positions of HVSI switches:
Position 0: - QVSI and MVSI isolated
Position 1: - QVSI and MVSI in service
Position 2: - QVSI in serviceand MVSI isolated
Position 3: - MVSI in serviceand QVSI isolated
BLOWER MOTOR FOR SMOOTHING REACTOR (MVSL 1&2): These motors (MVSL1&2) areused
for cooling smoothing reactor 1& 2. Proper working of motors (MVSL1&2) can beensured by
airflow relays QVSL1&2 respectively. Theswitches HVSL1&2 areprovided on the TB board for
controlling working of Motors & relays. Whenever any blower does not work, respectiverelay
de-energizes and trips DJ through relay Q118.Thesearedirectly start motors along with ARNO.
This is an axial flow motor with 2.2 kW capacity. Following are the positions of HVSL switches:
Position 0: - QVSL and MVSL isolated

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Position 1: - QVSL and MVSL in service
Position 2: - QVSL in service and MVSL isolated
Position 3: - MVSL in serviceand QVSL isolated
OIL PUMP FOR CIRCULATING OF TRANSFORMER OIL (MPH): The purposeof this motor is to
drive the oil pump to circulate transformer oil. A relay QPH is provided to check working of the
oil pump. QPH is a pressurerelay provided on the pipeline of the oil circulating systemof
transformer in the H.Tcompartment. When the pump is not working properly, therelay
causes tripping of DJ. HPH is provided on TB board for controlling MPH and QPH .The MPH is a
directly start motor and starts along with the ARNO. Following are the positions of HPH switch:
Position 0: - QPH and MPH isolated
Position 1: - QPH and MPH in service
Position 2: - QPH in serviceand MPH isolated
Position 3: - MPH in serviceand QPH isolated
MAIN COMPRESSORS (MCP 1, 2, 3): The purposeof these compressors is to build up
compressed air required for various purposes in the locomotive. These motors starts working
through contactors C101, C102, C103.Thesecontactors can beswitched ONby switch BLCP
(automatic) or by BLCPD (direct) on the Loco Pilots' desk. Main Compressor Governor RGCP is
provided to regulate the working of the compressor by opening and closing the contactors at
preset value (closes at 8 kg/cm2 and opens at 9.5 kg/cm2). A direct switch BLCPD is provided
to bypass RGCP and to make compressors to work continuously to build up pressureuntil
Safety valve (SS2) blows at10.5 kg/cm2. Compressorscan be selected according to
requirement through HCP.
EXHAUSTERS (MPV 1-2): The Exhausters MPV 1 & 2 is provided for creating and maintaining
vacuumon train pipe. These motors starts working through the remote control switch BLPV.
When BLPV is closed, according to ZPV positions, MPV-1 or MPV-2 will work. MPV-1 starts
working by closing C-121 Contactor and MPV-2 by closing C-111 Contactor. These exhausters
are provided with oil sumps for lubrication and provided with dipstick to check the oil level in
the sump.
BLOWER FOR COOLING TRANSFORMER OIL (MVRH): The transformer oilcooling blower motor
is provided for cooling the transformer oilin the radiator. On closing BLVMT firstC-107

40. 40
contactor closes and MVRH starts working. Thereis a relay QVRH to check the proper
functioning of this blower. Switch HVRH is provided on TB board for controlling MVRH and
QVRH. Switch HVRH has four positions same as HVSI.
BLOWER MOTORS FOR TRACTION MOTOR (MVMT1-2): These blower motors (MVMT-1&2) are
required to cool the traction motors in bogie 1 and 2 respectively. MVMT-1 starts working
through C-105 contactor and MVMT-2 starts working through C-106 contactor. Theswitch
BLVMT is common for starting MVRH, MVMT 1 &2. The blowers will start one after the other
with a time delay of 8 Sec with the help of QTD 105 and QTD 106. Airflow relays QVMT1&2
are provided to check the proper functioning of these blowers. If the blowers arenot working
properly, the particular relay interlock will open on Q118 branch of DJ control circuit and trips
the DJ. Switches HVMT1&2 are provided on TB board for controlling MVMT 1&2. Switch
HVMT 1&2 has four positions sameas HVSI.

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CHAPTER 9: PANTOGRAPH
9.1 INTRODUCTION:Itis a collapsible framework mounted on loco roof. Pantograph is
mounted on four base insulators. This frameis made of severalmetallic tubes and springs. Ball
bearings are provided for easy movement of articulations and at each joint, flexible shuntare
provided to give continuous flow of current. On the top frameof the pantograph, panto pan is
provided to collect the currentfromOHE. Panto pan is made up of high carbon strips, which
can be replaced when worn out. Normally the panto is in lowered position by the tension of
lowering springs provided insidethe servomotor. When compressed air is admitted inside the
servomotor, piston is operated and compresses thelowering spring.
The piston rod is attached to the rocker armand releases actuating rod, thereby the cam is
released and operates the lower articulation drum. When the lower articulation drumis
operated, the lower articulation is raised upwards by the action of raising springs. The upper
articulation, which is connected to the lower articulation at free end, will also rise by the
action of thrustrod. Thereby the upper articulation will rise. The tension of lower spring is
more than the raising spring. So it is necessary to admit the compressed air inside the
servomotor continuously. For lowering the panto, it is enough to exhaustthe compressed air
fromthe servomotor; thereby with the action of lowering spring panto lowers. Which in turn
operates the lower articulation rod against the tension of rising spring, due to this action the
lower articulation is pulled down and upper articulation is also pulled down simultaneously by
the action of thrustrod. The admission and exhausting of compressed air in the servomotor is
controlled by electro valves (VEPT1 & VEPT2), which are remotely controlled by ZPT fromLoco
Pilot’s desk. Each loco consists of two pantos. These are electrically connected by means of
HPT1, HPT2 and Roof bars. The OHE supply collected by panto is taken to the main
transformer through roof bars, DJ and roof-bushing bar. For isolating the panto PT1 & PT2 cot
out cocs are provided. PT1 cot out coc is provided in Cab1 center locker and PT2 cot out coc is
provided in Cab2 back panel.
9.2 PRINCIPLE: Basically, compressed air raises the pantograph and lowering springs of
servomotor lower the pantograph. The sole function of air is to cancel the lowering effortof
the springs (Servomotor) and it has no direct effect on the pantograph. When the pantograph
is working and the air pressureis maintained in the servomotor, thepiston is kept forward and
the articulated systemis entirely free to keep panto in raised position only. Therefore, It
absorbs freely all the oscillations of the contact wire. The equipment lowers by itself when

42. 42
pressuredrops below 3 to 3.5 Kg/cm². All parts of panto are alive and used as conductors. The
currentcollection is made on the framewith shunts fitted at all moving points.
Minimum air pressureto raisepanto: 4.5Kg/cm2
Nominal pressure: 7Kg/cm2
Rising time: 6 - 10 sec
Lowering time: 10 sec or below
Rated current: 400 Amps
9.3 RAISING: Air is admitted to servomotor cylinder. The piston compressed the holding down
springs and displaces the slotted link. This permits the rotation of the horizontalspindle under
the action of up springs. The pantograph rises until the collector plate reaches the catenary.
The articulated systemthen stops and piston complete its stroke. Fromthis point onwards the
air motor plays no further partand piston remains stationary during normal operation. The pin
of the horizontal spindleis permitted to move freely in the slotof the control link. The panto
operates purely on the up springs, thedesign is such as to permit free movement of the
articulated systemthroughoutfull distanceof its raise and fall.
9.4 LOWERING:Opening of the control cylinder to atmospherecauses piston to return under
the forceof holding down springs slotted rod presses on the pin of the horizontal spindle
thereby lowering the articulated system.
The throttle valve allows the adjustments of the lowering and raising steps of the pantograph.
The raising speed depends up on only on the gauged hole. The lowering takes place in two
stages the firston quick stage and second on the slow stage. Pantograph mayberaised or
lowered fromcabin by any of the following methods.
a) Air raised gravity lowered.
b) Air raised spring lowered.
c) Spring raised air lowered.
9.5 REASONS FOR USING THEREAR PANTO:
1. Itgives the smooth passage for the panto.
2. Itavoids the spark coming fromthe Loco Pilots desk.
3. In caseif any damage occurs to the panto, the damaged parts of the panto will be
thrown out of the train.

43. 43
4. At the time of entering into the unwired track or any defect is noticed in OHE, if DJ could
not be opened while approaching neutral sections, there is possibility for the Loco Pilots
to lower the panto which can avoid panto entanglement.
Figure 11: Panto pneumatic circuit

44. 44
CHAPTER 10: MOH SECTION
10.1 INTRODUCTION:MOH section deals with the major overall of the engine. The engine as
per its schedule (18 Months) is broughtto its home shed for its maintenance and is first
reported to the MOH section. This section then identifies the fault partand then refer it to the
section concerning to it. For example if the traction motor is giving a fault then it will be given
to the traction motor section for its repairing.

45. 45
CHAPTER 11: PNEUMATIC SECTION
Pneumatic section is the mechanical braking systemin the locomotives which is achieved by
the compressed air in the cylinder. The pressurized air comes from an air compressor in the
locomotive and is sent fromcar to car by a train line made up of pipes beneath each car and
hoses between cars. The principle problem with the straightair braking systemis that any
separation between hoses and pipes causes loss of air pressureand hence the loss of the force
applying the brakes. This could easily causea runaway train. Straight air brakes arestill being
used n the locomotives although as a dual circuit system, usually with each bogie having its
own circuit. There are two types of brakes used in LOCO:
AIR BRAKES: The compressed air is used for obtaining brakeapplication. The brakepipe and
feed pipe run throughout the length of the coach. Brakepipe and feed pipe on consecutive
coaches in the train are coupled to one another by means of respective hosecouplings to form
a continuous air passagefromthe locomotive to the rear end of the train. The compressed air
is supplied to the brake pipe and feed pipe fromthe locomotive. The magnitude of braking
forceincreases in steps with the corresponding reduction in brakepipe pressureand vice-
versa.
VACCUM BRAKES: The vacuumbrakesystemderives its brake forcefromthe atmospheric
pressureacting on the lower side of the piston in the vacuumbrakecylinder while a vacuumis
maintained abovethe piston. The train pipe runs throughoutthe length of the coach and
connected with consecutivecoaches by hose coupling. The vacuumis created in the train pipe
and the vacuumcylinder by the ejector or exhauster mounted on the locomotive.
WORKING:Application of loco brakealong with formation brakes is called proportional
working. When BP pressureis dropped, C3W valvesenses the droppage of BP pressure. C3W
valve senses when BP drops 0.6kg/cm2
within 6 seconds. When BP drops in loco, C3W acts and
it takes proportionate MR4 pressureand passes via 2kg/cm2
limiting valve and acts on VEF (m).
Now VEF (m) admits MR4 pressureto C2B valve through F1 selector valve and double check
valve. C2B valve now takes MR4 pressureand send to loco brakecylinders when both trucks
bogie isolation cocs arein open position. To isolate loco brakeapplication by A9, press PVEF.
Now VEF (E) energizes and admits MR4 pressureto VEF (M). Now VEF (M) exhaust portis
connected to C2B. The existing pressurefromC2Bto VEF (M) becomes ‘0’. When there is no
actuation on C2B, the brakecylinder pipe line is connected to C2Bexhaust port there by the
brakecylinder pressurebecome‘0’ and brakes are released.

46. 46

47. 47
CHAPTER 12: POWER SECTION
This section deals with the power instruments used in the locomotive such as VCB, oils in the
transformers testetc.
TRANSFORMER: Transformer is a static device used for stepping up or stepping down the AC
supply voltage (In traction is intended for stepping down fromOHEcatenary supply of 25 KV to
1750 V and 380 V). This is located in the HTcompartment of the locomotive. It is an oil
immersed type with forced circulation cooling. The power fromOHE collected through
pantograph and circuit breaker is supplied to the regulating winding of the Auto transformer.
Arrangementof the various windings on the limbs of transformer is as shown in the diagram.
The transformer has 3 limbs. The firstlimb carries the windings of auto transformer regulating
winding. This winding is provided with 32 taps. The wining is suitable for giving a rated output
of 3640 KVA. Thetapings taken out are connected to tap changer. The tap changer is driven by
SMGR driven by air motor. The air motor can be operated even with minimum air pressureof
3 kg/cm2. Another auxiliary windings (TFWA) is intended for supplying singlephase 50 HZ, 380
± 22.5% volts supply to ARNO converter. The coil is suitable for 180 KVA load. The primary
winding (A0 – A34) and secondary winding (a3 – a4 and a5 – a6) are carried on limb 2 and limb
3. The primary winding consists of two groups in series on limbs 2 and 3. The secondary
winding consists of four groups and occupies symmetricalgroup positions on limbs 2 and 3 in
relation to primary groups. Allthe coils are disc (or pan cake) type sincetap changer oil is
subjected to heavy duty (i.e. arcing during movement of contact roller on contact segments) it
requires frequent changing and maintenance as compared to transformer oil. So the
transformer oilis sealed off fromtap changer oil such as to facilitate drawing out of tap
changer oil alone for maintenance purposecooler is (MVRH) mounted on the transformer
cover oil circuit pipe line connections need not be removed for maintenance. Recent
developments in sometransformers areSF6 gas cooling is used. The transformer magnetic
circuit consists of laminated magnetic cores interleaved to formthe three limbs. H.V. circuit is
connected to DJ through condenser type bushing. The upper bushing is mounted on the roof
of the locomotive. The lower bushing is fitted on the cover of transformer and middle part of
bushing (in between) is screwed to the bottom bushing. The secondary winding (L.T.) is
connected to the external circuit taken out of transformer through 4 bushings and arealso
mounted on the cover of transformer. Oilconservator is situated above the transformer. The
pipe leading to it is serving as a safety valve having an oil over flow chamber aboveit. The oil
over flow chamber has a dischargepipe to lead the blown out oil down underneath the
locomotive body. This complete systemthus acts as a pressurerelief device. The oil pump and

48. 48
the cooler are connected to the conservator by a venting pipe. Air does not come in contact
with the oil directly. The moisture in the air entering breather is completely absorbed by silica
gel acting as an air dryer.
VACCUM CIRCUIT BREAKER: Vacuumcircuit breakers arereplacing the air blastcircuit
breakers used on electric Locos/EMU'S due to following advantages.
1. Less Maintenance
2. Greater Safety
3. Greater Reliability
4. Simplified Control
5. Noiseless Operation
CONSTRUCTION: The main switching unit consists of two vacuuminterrupters connected in
series and are mounted in the Horizontalsupportinsulator. Each interrupter houses a pair of
contacts. The interrupters operating rods are connected to a pneumatic dual piston. Operating
mechanismis mounted in the main cradle between the interrupters, which closes the contacts
by the application of air supply. The contacts are held normally open by heavy-duty springs.
When actuating rod through the crank pins, operates auxiliary DJ interlock unit. Itis fixed to
the spring plate. The relay valve body is bolted to one side of the air cylinder. The controlair
pipe and main air pipe, which are made up of special nylon, are routed between the relay
valve and the base of the circuit breaker inside the insulator. The regulated and filtered air
pressureof 5 Kgs/cm2
is supplied fromair reservoir QPDJ setting is kept at cut in 4.65 Kgs/cm2
and cut out 4.0 Kgs/cm2
.
OPERATION: When the magnet valveis energized, controlair is admitted to the bottom
chamber of the air relay valve and pushes the puppet valve upwards to allow operating air
through main pipeline in to the cylinder via 2mm diameter choke. The operating air in the
cylinder piston moves outwards againstthe pressureof springs, thus closing the contacts in
those interrupters. Air cylinder has small and large ports. When the magnetic valve is
energized air enters in to the cylinders firstthe small port and then at through energized touch
with each other by the large port, thus the contacts are fully closed. When the magnet valveis
de-energized the cylinder exhausts to atmospherethus causing the piston to accelerate rapidly
inwards by the face of springs.
POTENTIAL TRANSFORMER: Theprimary voltagetransformer is situated on the converter roof
hatch and attached to the pantograph via the roofline. The primary voltage transformer
reduces the catenary voltage, approximately 25 kV, to 200 volts AC. A resistor is placed across

49. 49
the primary voltage transformer to provide a reference load. The output signal is used in three
ways;
1) Main converter electronics = 4 volt AC
2) Catenary voltmeters on the driver’s console = 10 volt DC
3) Minimum voltage relay.
When panto is raised this potential transformer fed to U meter and U meter shows the
OHE supply in drivers cab. As such we can have an idea of availability of OHE supply before
closing DJ and also idea of rising of panto. However our responsibility of seeing panto is not
finished, we have to check the condition of panto physically.
Figure 12: Traction power circuit

50. 50
HARMONIC FILTER: Line harmonic filter is connected with primary winding of main
transformer which consists of resistances and capacitor. This harmonic filter
reduces/suppressed the high frequency harmonics to avoid disturbances in signaling.
If the harmonic filter gets bypassed by the system, the speed of the loco / train will be
automatically restricted up to max 40 KMPH by CE.
BATTERY: In ABB loco NiCD Battery is used. There are total 78 cells in the batteries which are
placed in 2 boxes at either side of the locomotive. Each box contains 39 cells and each battery
has 3 cells. Capacity of battery is 199 A-H and output is 110 V. To charge the battery, one
battery charger is provided with circuit breaker no. 110 situated in SB2. Main switch for
battery is 112 which is placed in a box provided near battery box no. 2. For control circuit
supply 1 MCB no. 112.1 is provided in SB2. To show the battery voltage UBA is provided in
either cab.
Note:-
1. If battery voltage is 92 V for more than 30 seconds, P-2 Fault will appear on the screen.
2. If charging current is reduced by 10 A, P-2 fault will appear on screen.
3. If battery voltage is reduced below 82 V, P-1 message with shutdown of loco will appear.
4. If cab is activated and panto is lowered than 10 minutes CE will switch off automatically.
5. Loco CE get power supply directly from battery and can supply upto maximum 5 hours.
6. For machine room light power supply is given directly through MCB 327.4.
Technical Specification:
Cell model = SBL-199
Cell type = Nickel/Cadmium
Number of cells per battery = 3
Number of batteries per battery box = 13
Number of battery boxes = 2
Total nominal capacity = 199 Ah
Nominal voltage of each cell = 1.4 V
Total battery voltage = 1.4 x 3 x 26 =110 V

51. 51
CHAPTER 13: ELECTRONICS SECTION
This section consistof the electronics instruments such as CHBA (Battery Charger), AC
damping panel, static converter, RSI block, SL block, SR power converter etc.
STATIC BATTERY CHARGER (CHBA): Battery charger is a static device for charging the batteries
as well as to maintain the controlcircuit in energized condition. After closing DJ, it receives
380V supply fromARNO. The charger has a step down transformer to step down 380 V ac. into
110V ACand further converted to 110V DCsupply by means of a bridge rectifier. The output of
CHBA (110V DC) is fed to batteries for charging as well as for energizing controlcircuit. When
the charger is kept in working condition, relay QV-61 willenergize and lamp "LSCHBA"
extinguishes by opening it’s normally closed I/L in signaling circuit. An Ammeter is provided on
battery charger to indicate the rate of charging. A voltmeter UBA along with ZUBA is provided
to measure the battery voltage and charger voltage. UBA indicates battery voltage only when
DJ is in open or HCHBA is placed on zero. A fusetester ECC is provided with lamp LECC across
the batteries to check the condition of the sparefuseavailable in TB panel.
180 kVA STATIC CONVERTER:
System Description: The converter generates 415V, 3-phase, 50Hzoutputfrom760V /830V, 1
phase, 50Hz inputwhich is available fromthe main locomotive transformer. General
schematic of the converter is shown in below figure.
Converter schematic diagram: Thestatic converter is made using a half controlled single phase
bridge rectifier at the input, a DC link filter and a three phaseIGBTbased PWM inverter. All

52. 52
functions of the converter are controlled through 32 bits digital signal processor (DSP)
together with a EPLD & hostof digital gates and analog amplifiers.
This converter consists of the following sub modules:
 Rectifier Circuit
 Overvoltagechopper
 Inverter circuit
 Gate drive circuit
 Controller circuit
TRACTION CONVERTERS (SR): Traction converter converts single-phase 25 KV AC supply into 3
phase AC, with Variable Voltage (max 2180 V) and frequency (from 65 to 132 Hz) while
traction mode and fed it to traction motor group -1. As such there are two traction converter
i.e. Traction converter-1 for TM 1-2-3 and Traction converter-2 for TM4-5-6.( In caseof WAP-5
, traction converter-1 for TM 1-2 and Traction converter-2 for TM-3-4) While electrical braking
the traction motor works as a generator and fed generated 3-phase supply to Traction
converter. This converter now act in reverse manner i.e. it converts 3 phase AC supply into
single phase AC supply and fed it to Transformer. Further main transformer steps up this
supply and fed back to OHE. In this way 3 phase loco works as a small powerhouse, which
generate supply and share the load by feeding it back to OHE. SR is cooled by two separate oil
cooling unit. The traction converter has three main sub parts:
1) Line Converter
2) Intermediate DC link and

53. 53
3) Drive converter.
One spy glass is provided on each SR to check the oil level.
SILICON RECTIFIERS (RSI BLOCK): The main rectifier consists of two identical cubicles. Each
cubicle houses the diodes, Fan, bridges-fuseetc. The output of each rectifier feeds a group of
three traction motors. Each cubicle is provided with 6 bridges connected in parallel and
protected by bridgefuses. In the event of failure of any of the bridges, the bridge fuseblows,
triggering in turn the signaling fusewhich lights up a signal lamp LSRSI on the driver’s desk.
Each cubicle is fitted with one axial flow blower driven by 3 ph motor (MVSI 1-2)
No. Of cubicles per loco 2
Rated current 3300 Amps
Max. Starting current 4050 Amps
No Load rated voltage at 22.5 KV 750v dc
Connection Bridge
No. Of bridges 6 per cubicle
No. Of Diodes 4 per bridge

54. 54
CHAPTER 14: WHEEL SECTION
Generally in all locomotives solid wheel is used due to the needs of increase traffic, higher
speed, steeper gradients all of which demand stronger braking. The profiles of new tyre/
wheels are as follows:
Diameter New 1092mm
Worn 1016mm
Minimum width of tyre Coupled wheel 133mm
Other than coupled wheel 127mm
Thickness of tyre flanges Thick flanges 32mm
Standard flanges 28mm
Thin flanges 18mm
Thread 63.5mm
Distance between wheel set 1596 ± 0.5mm
Some locos are provided with renewable steel tyres and tyre as per specification IRSRIS- 64 oil
quenched with tensile strength of 100-110 Kg/cm2. Other locos areprovided with solid wheel
disc conforming to specification, IRS M2-65 and IS 1030-1962.
The diameter of new wheel size of WAG5, WAM4, and WAP type locomotives is 1092 mm. The
condemning diameter is 1016 mm.

55. 55
CHAPTER 15: LAYOUTS OF LOCOMOTIVE
Figure 13:Bogie Layout

56. 56
Figure 14: Roof layout
Figure 15: Front connections

57. 57
Figure 16: Cab layout

58. 58
Figure 17: WAG 9/WAP7 machine room layout

59. 59
Figure 18: WAP 5 machine room layout