This document discusses gear failure in electric locomotives. It begins with an introduction to electric locomotive sheds in India and describes the operation and components of electric locomotives. It then defines gears and classifies different types of gears. The main types of gear failure are described, including wear, corrosion, abrasion, pitting, scoring, and fracture. Methods for analyzing gear failures, such as dye penetration testing, metallurgical analysis, and ultrasonic testing are also outlined. The document concludes by thanking those involved in the electric locomotive shed for their support and guidance.

1. GEAR FAILURE
SUBMITTED BY:
ANUJ KUMAR MISHRA

3. CONTENTS
• Introduction and History of Indian Railway
• Introduction of Electric loco shed, Kanpur
• Characteristics and operation of electrical locomotive
• Traction motor
• Project study
• Definition of Gear
• Types of Gear and their uses
• Types of Failure and Preventions
• Failure analysis
• Conclusion

4. ACKNOWLEDGEMENT
We take this opportunity to express our sincere gratitude to the
peoples who have been helpful in the successful completion of
our industrial training and this project. We would like to show
our greatest appreciation to the highly esteemed and devoted
technical staff, supervisors of the ELECTRIC LOCO SHED, KANPUR.
We are highly indebted to them for their tremendous support
and help during the completion of our training and project.
We are grateful to Mr. N.P Singh (S.S.E) who guided us in
successfully completing industrial training in the shed. We would
like to thanks to all those peoples who directly or indirectly
helped and guided us to complete our training and project in the
shed, including the following instructors and technical officers of
electrical Training Centre and various sections.

5. ABOUT THE ELECTRIC LOCO SHED
KANPUR
• The Electric loco shed, Kanpur was established during the year 1965
for homing 11 locomotives. This shed was commissioned primarily
to meet the requirement of passenger and goods traffic over Indian
railways. At present the shed has been expended suitably to home
203 loco motives for hauling, passenger and goods traffic.
The shed is responsible for carrying out monthly inspection
schedule viz. IA, IB, IC, I0 & ICO in addition to annual and
intermediate overhauling schedules.
48 - WAP-4
152 - WAG-7
3 - WAM-4
MAJOR INSPECTION - IOH AND AOH

6. OPERATION OF LOCOMOTIVE
• The electric locomotive basically works at 25 KV, 50Hz supply. The 25KV AC
supply is drawn from overhead catenaries wires. The supply from
overhead wires are drawn through a pantograph inside the loco
transformer. This transformer is an autotransformer from which regulated
voltage is taken to a rectifier block for conversion from AC to DC .It may be
worth mentioning that the final tractive effort is through DC traction
motor hence AC is required to be converted to DC. The DC current from
rectifier block is then filtered to pure DC and then fed to traction motor.
• There are 6 traction motors which works parallel to provide the attractive
effort for hauling the train.
• All the operations are controlled through control circuit which works at
110 volt DC. Various power equipments during operation gets heated up
and hence to cool the same, it is done by various blowers.

7. DEFINITION OF GEAR
A gear may be defined as any toothed member designed
to transmit or receive motion from another member by
successfully engaging teeth.

8. CLASSIFICATION OF GEARS
Gears may be classified as given below:
 Based upon the shape of gears
1. Spur gears
2. Helical and herringbone gears
3. Bevel gears
4. Spiral gears
5. Worm gears
 Based upon the orientation of shafts
1. Gears for parallel shafts e.g. spur gears, single helical, and double helical gears.
2. Gears for intersecting shafts, e.g. straight bevel, spiral bevel.
3. Gears for non-parallel and non-intersecting shafts e.g. spiral gears, hypoid gears, and worm gears.
 Based on speed reduction
1. Up to 3:1 -------------- bevel gears
2. Up to 6:1 -------------- single pair of spur or helical-
3. Gears
4. Up to 10:1 -------------- two stage or three stage reduction
5. Spur or helical gears
6. From 60:1 to 100:1 -------------- worm gears

9. FAILURE OF GEARS AND THEIR
PREVENTION
WEAR: a surface phenomenon in which layers of metal are removed, or
“worn away” more or less uniformly from the contacting surface of the gear
teeth.
CORROSIVE WEAR: this is a deterioration of the surface due to chemical reaction. It is
often caused by active ingredients in the lubricating oil, such as acid, moisture, and
extreme-pressure additives.

10. ABRASIVE WEAR
When abrasive wear has taken place, contacting surfaces show signs of a
lapped finish, radial scratch marks or grooves, or some other unmistakable
indication that contact has taken place.

11. PITTING: a surface fatigue failure which occurs when the endurance limit of
the material is exceeded, a failure of this nature depends on surface contact
stress and number of stress cycles.
Pitting phenomenon is of two types:
• Initial pitting
• Destructive pitting

12. SCORING: rapid wear resulting from a failure of the oil film due to
overheating of the mesh, permitting metal to metal contact; this contact
produces alternate welding and tearing which removes metal rapidly from the
tooth surfaces.

13. FRACTURE: failure caused by breakage of a whole tooth or a substantial
portion of a tooth; this can result from overload or, more commonly, by cyclic
stressing of the gear tooth beyond the endurance limit of the material.
FATIGUE BREAKAGE: gear tooth failure from bending fatigue generally results
from a crack originating in the root section of the gear tooth. The whole
tooth, or a part of the tooth, breaks away. Most often there is evidence of a
fatigue “eye” or focal point of the break. The break shows signs of fretting and
conventional smooth beach marks in the break area.

14. FAILURE ANALYSIS
In this section we will study about:-
• RDP test.
• Metallurgical lab.
• Ultrasonic test
RED DYE PENETRATION TEST (RDP)
Dye penetrant inspection (dpi), also called liquid penetrant inspection (lpi), is a
widely applied and low-cost inspection method used to locate surface-breaking
defects in all non-porous materials (metals, plastics, or ceramics). Penetrant may
be applied to all non-ferrous materials, but for inspection of ferrous components
magnetic particle inspection is preferred for its subsurface detection capability.
Lpi is used to detect casting and forging defects, cracks, and leaks in new
products, and fatigue cracks on in-service components.

15. METALLURGICAL LAB
Metallurgical lab. Concern with the study of material composition and its
properties. Specimens are checked for its desired composition. In this section
various tests are conducted like hardness test, composition test e.g.
determination of percentage of carbon, swelling test etc.
ULTRASONIC TESTING
In ultrasonic testing, very short ultrasonic pulse-waves with center
frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz are
launched into materials to detect internal flaws or to characterize materials.
Ultrasonic testing is often performed on steel and other metals and alloys,
though it can also be used on concrete, wood and composites, albeit with less
resolution. It is a form of non-destructive testing.

16. Conclusions
• Traditionally, locomotives pull trains from the front. Increasingly common is push-
pull operation, where a locomotive pulls the train in one direction and pushes it in
the other, and can be controlled from a control cab at the other end of the train.
•
• Like great books, no project is created entirely by an individual. There are many
people involved in this project too and have helped a lot right from the beginning
till the completion of our project. Any bouquets for the merits in this project
should go to our door. Any brickbats we are ready to catch ourselves.
• It is with a great sincerity, we convey our heartful gratitude to our Mr. Mohammad
Israr, Supervisor, Electric Loco Shed, Kanpur, for his excellent guidance, valuable
advice and ample co-operation throughout the training. It is a proud privilege to
have availed of the opportunity of guidance.

17. …Contd
• We are thankful to Mr. N.P SINGH too, for their excellent cooperation
during our training for the proper response of the machine. We are
grateful to all the railway employees.