Critical Thinking

Sumit flange by the rail line results in

Sumit U. Choudhari, Rajat R. Badwaik,
Satish R. Kavre, Mangesh T. Pardi, Pawan S. Barange, Sanjay G. Achre

Mechanical Department, Nagpur


Abstract— Wheel deformation is one of the major failures in Indian Railways.
In this paper we study the most efficient methods of wheel maintenance for
interaction of dynamic forces and rate of wear between rail and wheel. The erosion
of wheel influence the dynamic characteristics of the vehicle and the dynamic
force strike on the wheel flange by the rail line results in derailment. The erosion
of wheel mostly depends on abrasion and inappropriate maintenance on board. Therefore
the wheel should take into consideration as the major derailment happens due to
wheel deformation of the ride. When brake applies on ghat sections and down
gradients due to continuous application and releasing of brakes, defects such
as pitting mark, wheel shelling and heat check occurs.


Keywords— Derailment, Pitting mark,
wheel shelling, wheel deformation, wheel failures, Indian Railways.

I.     Introduction

Wheels are the important component of
every vehicle, to make vehicle more efficient and comfortable, wheel plays an
important role. Therefore the maintenance should be proper and defects should
be minimised for generating optimum output. Most of the population in India
travel through railways. Hence the travelling vehicle should have minimum
failures, so that people should not face troubles and causalities. For this,
vehicle mainly wheels should be properly maintained and have lesser defects in
it. After 2016 India stared using LHB (Linke Holfmann Busch)
coaches which are lesser in weight and have designed to run at high speed. As
the speed is more the application of brake should work efficiently and all
comes to wheel to stop the train at right time. This deals more damage to the
wheels. As wheel failures already a huge problem in railways hence we must have
to focus on wheel conditions and its failures.

II.   wheel Defects

Wheel is the most dynamic part in
railways, also make vital role in safe travelling. In railways wheel make two
important functions i.e. bears the weight as well as guiding the wagon hence
defects in wheel leads to a serious damage. And mainly defects are found in
wheel profile. Some of the defects are as follows

Sharp Flange- When radius of
flange is wear up to 5mm. This defect is known as sharp flange. Due to continuous
hitting of flange the inclination of flange reduces and can cause derailment.

Deep Flange- If depth in flange
is wear up to 35mm, this defect in wheel is known as deep flange, this can
damage to fish plates, fish bolts, and check bolt also a cause of derailment
mainly at check blocks.

Hollow tyre- because of erosion on the wheel tread caused
by inappropriate brake block material composition, the the wheel tread wears
out and forms the arc due to inclination given on the wheel.

Thin tyre- Generally the thin tyres recognised
by thickness of the tyre, may reduce up to 25mm.

Thin flange- in this type the
thickness of flange minimizes up to 16mm. The thickness of flange must be
calculated at the 13mm from the tip.

III.  how does it occur?


1)      During ghat sections and down gradients continues application and
releasing of brakes should be done, so that vehicle should not attends high
speed. Due to continues application the temperature of the wheel increases and
becomes warms, and cools due to surrounding temperature, due to continuous of
this treatment material becomes hard and wear out some chips called as shelling
of wheel, heat check forming of wheel tread.

2)      If brakes not fully released by loco pilot from engine, or defect in
break equipment some of wheel defects occurs such as flat tyre, metal
deposition on wheel tread.

3)      Inertial drag due to sudden movement of the train at start can cause
flat tyre.

4)      Brake block composition also develops the defects in wheels.

5)      Brake block boundaries fail and break block back plate touching to
the wheel trend also develop grove in wheel trend.







IV. parameters for defect allowance

Type Of Defect

Designed Parameter

Allowed Limit

Sharp Flange

14.5 mm

Less than 5 mm

Thin Flange

28.5 mm

Less than 16mm

Less radius at root of flange

16 mm-IRS 14 mm-WWP

Less than 13 mm

Hollow Tyre


5 mm or above

Deep Flange

28.5 mm

More than 35mm

Thin Tyre


Since no tired wheel, dia of the wheel is the

Flat Tyre


50 mm or more-Coaching 60 mm or more –Goods


 Table 1. – Allowed limit parameters with type
of defect


V.  Remedies


While application of brakes
from train engine sufficient time to be used for releasing the brakes.

Brake component i.e. D.V., S.A.B,
B.C., check properly during maintenance and follow time to time oiling and
maintained piston stroke.

Maintained brake power
according to wheel diameter.

Standard brake component to be
used in braking system.

Specify breaking block to be
used during maintenance and time to time replace before allowed limit.

No break pressure leakage allow
in brake power pipe, joints, air hoes, D.V., B.S.Y.L. and antilock.

Maintained B.P. and F.P. pressure
in prescribed limit i.e. 5kg/cm2 in engine and rear brake is 4.8 kg/cm2
and F.P. in engine 6 kg/cm2 and rear brake valve 5.8 kg/cm2

Time to time maintenance schedule
should be carried out.

Check wheel in schedule maintenance
after applying gauge.

Before start the train check
break power properly released throughout the train.


VI.  Conclusion

Defects present in wheel may cause
unwanted noise and vibrations which are uncomfortable to the passengers, more
power would be required to carry the defected wheel. Defected wheel may cause
of derailments, excidents also can cause damages to the other part of the
wagon. Major derailments occurs in Indian Railways to avoid such type of
problems prescribed remidies should be take into consideration.