Transportation Engineering-II
Dr Rajat Rastogi
Department of Civil Engineering
Indian Institute of Technology - Roorkee

Lecture-7
Rails
Dear students, I welcome you back to the lecture series of course material on
transportation engineering 2. In the previous lectures we have already discussed about the
elementary sides of various cases like what are the permanent ways, what are the
specications, the gauges being used on the Indian railways, the resistances offered by
the tracks under stressesor the bending moments etcetera being caused in the different
components of the track. Now we are starting with another aspect of the railways that is
the components of tracks. In todays lecture we will be covering the aspects related to
rails. The some of the aspects which will not be covered today will be covered in the
subsequentlectures. In the rails we will be taking the functions of the rails, the type of
rail sections, the selection of rail sections, the length of rail, the test conducted on rails
and rail deformation or defects. These are the things which we will be taking up in
today s lecture.
(Refer Slide Time: 01:34)

So starting with the functions of the rails, the rails are provided so as to have a continuous
and leveled surface on the track. Rail is a surface which provides the surface for the
movement of wheels. If this is not continuous and if it is not leveled then obviously it is
going to create some disasters or hazardous conditions as we have seenin the case of the
stressesor the moments which can be induced in any of the components of the tracks in
the previous lectures.

(Refer Slide Time: 04:00)

Another thing is that it should require to have a smooth surface so that the frictions are as
low as possible. Then it also provides the lateral guidance to the wheels. In the case of the
wheels as we have seen may be in the coning of the wheels or any other diagram where
the interaction of the wheel with the rail is being shown, what we nd is that anges are
provided on the inner side of the rail section to the wheels. So that when there is a lateral
movement of the wheel in any outward or inner direction then the wheels are not going
away from the rail section. So that is how the rail sections are providing lateral guidance
to the wheels. If this lateral guidance to the wheels is not available then there will be a
derailment condition becauseof the slippage of the wheels over the rail sections. Further
it bears stresseswhich are developed due to vertical loads, thermal loads or breaking
effects.

In the previous lectures we have seen that there are stresseswhich are caused becauseof
different

reasons.

All

those

stresses

needs

to be counteracted

or to be taken

care of. The

rail is one of that system which has to bear the stresseswhich are coming directly from
the wheels to it. So that is why whatever types of stressesare being developed becauseof
any of the reasonsthey should be able to bear them without failure. further they should be
able to transmit those stresses loads which are coming from the top that is from the
wheels with the lower areasto a greater area below. If they are not transferring the load to
a greater area below then because of the concentrated load conditions or the pressures
being induced at any of one location there will be chances that there is a permanent sort
of a deformation get created at that location and if there is any permanent deformation
which is getting created at the location finally it is going to culminate into surface
irregularities and the failure of the track. Now we are looking at some of the requirements
of the rails

sections.

The very first thing is the composition of the steel should be proper. Whatever is the
material which needs to be mixed so as to form that rail section, in whatever proportions
they needs to be mixed, in whatever grades they need to be mixed that should be proper

then only the proper strength properties of that rail section will be achieved otherwise
there

will

remain

certain

sort of defects

in it.

(Refer Slide Time: 07:00)

.31.. as mgrmsiw

Another thing is that the rail sections should be economical in nature. When we say it
should be economical in nature we have to look at three components along with
economy. It should not happen that we provide a so small rail section that it is not in a
position to take up the loads which are coming from the top or it is not in a position to
sustain or to provide the guidance to the wheel system. The three aspects which needs to
be taken care are strength durability and stiffness. We cannot compensate or we cannot
remove or we cannot eliminate, we cannot reduce any of the aspectsrelated to these three
things. The strength which is required should be there. It should be durable, it means
whatever are the effects of the temperatures or other corrosive effects because of the
location of the rail sections being provided in certain areas,they should be able to sustain
all such type of actions and they should be stiff as far as possible so that they can sustain
the type of load which are coming from different locations from different direction in
eccentric

condition.

If any of these three aspects are not taken care of or there is something being left in the
design procedure then it is going to culminate, it is going to finally reach the failure
condition of that rail section. So we have to get the economy along with reserving these
three things, that is, the strength durability and stiffness. Another important thing in the
design of rail section is that its CG should be as near as possible to the center of the
height. Now if the CG is very near to the center of the height then it will help in
balancing of the tensile and compressive stresses.If this balancing of the stressesis not
there and any of the stressesremoved then it is going to create its effects in terms of the
different types of defects which can get induced into the rail sections. So as to remove
that type of effect getting induced in we have to make sure and ensure that the CG is
coming very near to the center of the height. Now this is one of the rail section which is
being shown here

(Refer Slide Time: 07:27)

Here this rail section has three components. This component is known as the head, this is
known as web and this is the foot. This is another sort of a rail section where again this is
head, this is web and this is foot. This section where we are having a larger foot area is
known as at-bottom condition whereas in this case where it is not having a larger area it
is quite similar to what is being provided at the top that is the head. It is termed as the
bull

headed

condition

or the double

headed

condition.

So what

we can see is in this

case

that we have to design this area, we have to design this web area as well as the foot area.
So when are talking about the strength it means the head should be sufciently large
enough so as to take the loads which are coming from the top and dissipate them, web
should also have its sufficient strength so that because of the lateral loads which are
coming from this direction this should not break down because it is a thinner area and
foot should be able to provide the loads to a wider area which is possible basically in this
section becausethis is the total width which is available through which the same amount
of load will get dissipated where as in this case this area is so small. Now keeping in
mind this aspect we can look further the balanced distribution of material is to be done in
head web and foot. This is another important thing.

(Refer Slide Time: 10:00)

What is the total amount of the material which is to be put in these three sections? As we
have seenthe head is the section which is taking directly the total loads which are coming
from the top. Therefore it has to be a little wider. The web is to be designed in such that it
is stiff in nature and foot should be able to sustain the twisting conditions as well as
should be able to distribute to the load a larger area and looking at these three aspectsof
these three sections the distribution of the material has to be done. Next thing is that we
have

to look

at the economical

and balanced

distribution

of metal

where

the head

should

be able to have adequate depth so that the vertical wear if any is there is not creating an
effect by which we have to remove that rail section very frequently. Another thing is that
it should be wide enough so that the running surfaces whatever running surfaces of
wheels are there they should have sufficient movement over the top of that and a lateral
stiffness obviously has to be there because of the anges are getting the side of the rail
head and when they are hitting the side of the rail head then their stiffness has to be there.
If it is not there then it will break down at the point of contact of the head with the web.
Another thing related to the rail section is the height. It should have the sufficient vertical
stiffness and strength. Looking at the total amount of the loads which are coming in the
lateral direction we have to look at what are the bending conditions which will be created
and on the basis of this height those bending values can be computed. So we look at their
stiffness and their strength aspect and design it. Further, in the case of the web the
thickness has to be designed because it has to resist the lateral loads which are coming

from thetop in termsof theflanjucitionandat the sametimetherigidity, exural rigidity
has to be there. So this is the design aspect of the web.

(Refer Slide Time: 11:00)

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of

In the case of the foot becauseit is a point at which it is being connected with the sleeper
it should be stable enough and so as to have that stability it should remain wide in nature.
So if it is wide there will not be any overturning of that material of that component. The
next thing is the thickness. Now thickness is too provided because there are stresses
which are induced at this level of connectivity. The foot is connected to the sleeper using
fastening. If it is not thick enough then it will breakdown very easily and there will be a
failure of the system. In this regime it should be able to withstand the vertical and
horizontal forces after given allowances for different type of durability aspects like
corrosion

and effects

of corrosion

which

can reduce

the size of the section.

The next thing is we are talking about the shing angles where the design of the bottom
of the rail head and the top of the rails foot, they have to be designed in such a way that
whatever fishing plates are provided at the side they get t in.

(Refer Slide Time: 13:00)

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v- ai tamci itaaifazns.

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of

of

ail

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If they are not getting fitting in then there will remain some gap between the fishing
plates and the web of the rail section and because of that there will not be proper
transmission of load from rail to the sh plates. So the location at which the head is
connected to the web or the foot is connected to the web at that point whatever curvature
have been provided at that level the fishing angles have to be designed in that form so
that the proper connectivity is maintained.
Another point is then the llet radii should be large so that the concentration of stresses
can be reduced. Now looking at the extended sections; what are the types of sections
which

are available

to us so that

(Refer Slide Time: 14:02)

we can use them.

There are three types of rail sections one is double headed section. This double headed
rail section is also known as dumb-bell section. This is a sort of exercising equipment
dumb-bell where there is a thinner section in the center which is holding the hand and
then there is thicker section on both the sides which are same in nature. It means they are
having the same sort of dimensions. So it is designed to use from both the sides. The
philosophy behind designing of that type of section was that if there is wear and tear at
the top surface of the rail head then we can just make it opposite, that is, make the top
bottom and make bottom top so that we can use it from the other side, but what was
observed that because of the load conditions and because of the connectivity of the
bottom of that rail section with the sleeper through fastenings some indentations are
caused in that level and if you are turning it towards the up side then this indentations
will create surface irregularities and therefore running of the wheels will become
difficult.

It will

not be smooth

in nature.

Then another type of rail section which was used looking at these aspects was bull
headed

rail.

In the

case of bull

headed

rail

the head

was

made

a little

more

thicker

and

stronger as compared to the previous one where the both head and foot were of same
section and it means some more material is being added to the top of the head.
(Refer Slide Time: 14:30)

The philosophy here was that even if there is some wear and tear in this case it will
remain

as such and will

remain

in continuous

reuse.

Finally the third type of rail section which came was the at footed rail. The at footed
rail is also known as Vignoles rail after the name of its inventor Vignole.

(Refer Slide Time: 15: 10)

Under heavy loads in this case the foot is found sinking in the wooden sleeper that was
the case of the previous too one because the sections which was being provided at the
bottom, that is, as the foot where of a smaller section and if the heavy loads were coming
at the top then they were going inside of the sleepers. Initially the wooden sleepershave
been used and so it was found that they were penetrating the wooden sleeper whereas
now if we have the at footed rails then this is not the case. Another thing is that they
were requiring the bearing plates for load distribution, but in this case of the at footed
rail because larger area is available therefore generally the bearing plates may not be
required and they are now most commonly used in India. These are the comparative sort
of a diagram which is being shown here.
(Refer Slide Time: 16:06)

This is double headed rail section where this section and this section they are of similar
nature. It is a little higher than the another rail section which is bull headed rail section
where it has a sort of a bull head, that is, it is more stronger, bigger as compared to this
foot section and this is a at footed rail section where this top section is more or less sort
of a similar condition as this one with some sort of thickness or depth of the section being
reduced, but what we see is that the foot is being enlarged by a big amount. Instead of 6.
35 centimeter as a foot being provided here it is more than double of that one and this is
13.65

centimeters

in size at this

level.

So the merits of the at footed rails are; they are easy to fix, they are more economical,
they have greater strength and stiffness, they provide more lateral stability, there is no
requirement of keys or chairs which are required in the previous two casesthat is the bull
headed

and double

headed

rail

section.

(Refer Slide Time: 17:00)

The simple arrangementsare there at the points and crossings by which the directions of
the movement of the train can be made. We will be looking at the points and crossings in
some

There

other

lecture.

are of course

some

of the demerits

related

to the at

footed

rails.

There

is a demerit

in terms of the loosening of the ttings because of the thinner sections there are chances
that fittings get loosened out and there are some problems related to the strength
straightening of the bent rails.

(Refer Slide Time: 17:44)

If the rails have got bent due to some of the reason then it becomes a little difficult so as
to make them straight. There are all chances that at the bottom some breakage may take
place. Then at the time of replacing of the rails the problem is becausethey are not being
seated in the chair. So therefore, we take out the chair and replace it but here they have
been nailed down to the sleepers and becausethey have been nailed down to the sleeper
so all the ttings have to be taken out and then only these rails can be replaced. Then the
next thing is that dehogging of battered rail conditions because at the point of joint of 2
rail sections there are chances that the battering of the rail may take place. Battering of
the rail means, it is taking a nose dive at that location because of the impact of the
wheels. Now if that is going down at that location then it is to be brought back to its
normal level condition that is what is termed as dehogging and it is little difficult
condition

in the case of the at

footed

rail.

Now we come to the standard sections or designations which have been used in Indian
railways or otherwise. Now there are types of rail sections which have been used because
the British were the people who started the railways in our country.

(Refer Slide Time: 19:24)

So they used their own standards as I have told you in one of the previous lectures and
that is why we had the specifications from the British that is RBS sections or revised
British standard specications and in that case the rail sections were designated as 75 R,
90 R, 115 R likewise and this 75 R means this 75 pounds per yard section, 90 R means 90
pounds per yard section, 115 means 115 pounds per yard section.
Later on we had revision of all these and we are now having in Indian railways our Indian
specication where in we are using again the rail sections being designated in terms of
the weight per unit length but that is being taken as SI unit and here now we have two rail
sections one is 60 kg per meter rail section another one is 52 kg per meter rail section.
(Refer Slide Time: 20: 15)

The 60 kg per meter rail section is also termed as UIC section which is term which comes
from France and it is the union interationale

de cheminde fer, this is what is the

terminology stands for UIC section whereas 52 kg per meter rail section is IRS section
which is Indian railway standard section. Then the next type of the rail section which is in
use on meter gauge or narrow gauge, they stand with still we are continuing with those
standards specifications which came from British and they are 60 R section means 60
pound per yard rail section, 75 R section and 90 R section as specified before. Similarly,
in the case of rail sections for the narrow gauge it is 50 R rail section means it is 50
pounds per yard rail section. So these are the standard sections which are in use and this
is how they are designated in Indian railways.
(Refer Slide Time: 21 :02)

Now if we have to make a comparison of the different type of the rail sections which are
available to us then that comparison can be made on the basis of different factors like
strength. Strength means we have look at the load taking capacity of that section, whether
it is in a position to take much amount of load as we have seen in the comparative
diagram.

(Refer Slide Time: 24:04)

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What

we have

found

is that the head

of the bull

headed

rail

section

or doubled

headed

rail

section has been little more wider or thicker as compared to the head of the at footed
rail section. So in that senseprobably those have little more strength but as far as the base
is concerned then other one, that is the at footed rail section has some more strength.
Stiffness is defined in terms of the size of the web and the material or the thickness being
provided on the web. So it a little comparing condition but along with the fixation of that
rail section with the sleeper that stiffness can be increased. So it also depends on the
fastening which is being provided along with the rail section.
Then laying and relaying of the rail section as we have seen during a little smaller
comparison as we have done previously between the three types of the rail sections and
we have seen the merits and demerits of the at footed rail section. The laying and
relaying is a little difcult condition in the at footed rail section becausethe fastenings
are directly being inserting in that rail section or they are taking sort of you can say, they
are just xing it in a much more higher condition as compared to the previous two cases
where they are being placed in a chair. So you just take out a chair and the rail is being
taken

out.

Arrangements at points and crossings is another important aspect for the comparison
becauseso as to make a change in direction we have to look at this aspect; alignment and
stability. Stability is much more in the case of a at footed rail sections and because of
that there chances of having a better alignment condition in this one. Initial costing is
another aspect becausecost is the prime factor of starting with any of the thing whether it
is a laying or relaying of any component or the track. Further we can make that
comparison on the basis of the rigidity of the system, the rail sections, how rigid they are
when they are taking up the loads and then whether it is possible to make the inspection
of those

one.

(Refer Slide Time: 25: 15)

What is the ease of the inspection or what is the periodicity with which the impaction
inspection needs to be met? So we have to look at these two aspectswhether replacement
is to be taken in the form whether it is possible to make the replacement in an easier way
or it take it is a quite difficult to replace the thing. The maintenance aspect is taken in the
form at what is the periodicity with which the maintenance is to be done whether the
periodic maintenance is required at the level of weekly or fortnightly condition or it is to
be done at monthly basis or more than that. Suitability is another aspect that what are the
locations where those rail sections can be easily used. So whether that suitability is
available to all the rail sections or not, we have to take care of that.

Now coming to the next point is the selection of the section. Now there are different
factors which need to be taken care of in the selection. The very first thing is what of the
axle loads which are coming from the top.

(Refer Slide Time: 25:35)

Depending upon the heaviest axle load we have to use the type of the rail section and
there are certain relationship between the axle load and the type of the section. We will
be looking at that one. The maximum permissible speed is another aspect. If we have to
provide higher speed we require a better higher level of a rail section. Then what is the
depth of ballast cushion? If the depth of the ballast cushion is lesser, then obviously a
bigger rail section is to be provided. Then type and spacing of sleepers,that is the another
aspect. If the sleepersare of inferior type or they are having lesser of spacing so that now
these sleepers will be having more loads which are coming at that one, then also it is
going to create some effect at the type of the rail sections and this type of relationships
we have seen when we have seen the specification of permanent wheels. This is the
permanent type or way of the root then what is depth of the ballast cushion to be
provided? What is the sleeper density to be provided? Similarly, what is the rail section
which needsto be provided?
Now here the relationship is being given as I was talking that the axle load can be related
to the sectional weight of the rail, that is, in what kg per meter rail section is available to
us and the relationship is that the maximum axle load is 560 multiplied with the sectional
weight of rail in kg per meter.

(Refer Slide Time: 27:09)

So if we are talking about the 52 kg per meter rail or if we are talking about the 60 kg per
meter rail then that will get multiplied with 560 and it will give you the value of the
maximum

axle

load

which

it can

sustain.

So we can transform

this

axle

load

into

tones

and that is how the axle load of the locomotive will be dened. So what type of
locomotive

is to be used will

be defined

in this

form

or if we have

the locomotive

and we

have to seethat what type of rail section is to be provided then using that axle load of the
locomotive we can nd out the sectional weight of the rail so it is a vice-versa condition.
Now another thing is that how we specify any rail, so what is the brand of that rail? Now
there are different ways of doing it but we are using some way that is it is defined in
some form of this line which is being shown here and this will be engraved on the rail
section.

(Refer Slide Time: 30:00)

It is IR - 90 R - TISCO

- II 1985

- basic

BASSEMER.

Now

what

does

it mean

it means

IR is for Indian railways, 90 R means it is 90 pound per yard rail section being used here.
It may be 60, it may be 75 R. Then TISCO means this is a company which has
manufactured this rail section, II is for the month in which it is being manufactured, 1985
is the year in which it was manufactured and basic BASSEMER is the manufacturing
process by which that rail section has been manufactured. So this has been the previous
way of dening it.
Now

there

has been

little

different

modication

in this

one and what

we have

is this

IRS-

52 kg- 710- TISCO- II 1991 arrow OB; what it stands for is that it is Indian railway
standardsspecification IRS, 52 kg is the rail section as 52 kg per meter.
1710 is the grade of the rail. There is II grades of the rail one is the 710 another is 880
grade. TISCO is again the name of the company, II is again stands for the month and next
one is 1991 is for year and it says it is being processedby the process OB. OB is the short
form of again a sort of BASSEMER ordinary BASSEMER process of steel making. So
whatever

are

the

abbreviations

available

those

abbreviations

will

be

used

instead

of

giving the whole beginning of that one. Similarly, in the case of this 52 kg per meter rail
section, instead of this one as an alternative it may be 60 UIC rail section, this can be
given at this level. So this is the thing that will be engraved and each and every rail
section which is manufactured by any of the company and this tells us that what was year
in which it was manufactured and accordingly the replacement requirements can be
ascertained.

So another aspect related to rails is the length of the rail sections. The rails are
manufactured in different length. In the case of the broad gauge it is 12.8 meters and the
caseof meter gauge and narrow gauge it is 11.89 meters.

(Refer Slide Time: 31:05)

«WIQ?

So this is length of rail sections which is used. Now this is restricted, we are not having
the bigger rail section becauseof certain reasons. The one is that ease of manufacturing.
We can easily manufacture smaller rail sections as compared to the large long rail
sections

(Refer Slide Time: 31:15)

Anti §i.lé§3r"E'i,E~f

*

in

nag

Another aspect is the cost of manufacturing the bigger rail sections. It is quite large as
compared to the smaller rail sections. Then there is a lack of transportation facility of
such big rail sections. We require a big wheel base on which those can be transported.
Lifting and handling facilities are again of specic nature because it becomes a heavy
weight condition. So therefore, it will not be available at each and every place. So it is
better to have a smaller rail sections as compared to the bigger rail section.

Then if the rail section length is increasing it is going to also create an effect on the gap
requirements to be provided between the two rail sections which have jointed at one
level. Now because of that change in the temperature there will contraction and
expansion of the rail section and if the length of the rail section is more then there is
going to be proportionate increase in the movement in that direction may be in terms of
expansion. So it means a larger gap is to be provided between the two rail sections and if
the larger gap is being provided between two rail sections it will be a difcult situation as
far as the movement of the wheels is concerned over that. Then heavy thermal stresseson
long rails. This is as already discussed,it is going to take as a fact in terms of not only the
movement of the rail but also in terms of the gap requirements especially expansion gaps
which are to be provided. Looking at all these aspects the length of the rails has been
restricted to as what we have seen is 12.8 or 11.89 meter in the casesof broad gauge or
meter gauge or narrow gauge track conditions.
Now, coming to the 90 UTS sections. As we have seen that we have two types of the
sections which we have been using one is 72 kg per meter rail section another is 90 UTS
rail

section.

(Refer Slide Time: 33:41)

That is 90 kg per mm square ultimate tensile strength section and now this is heavier or
this is a section which is having a better strength condition. Here the tensile strength is of
the amount of 90 kg per mm square as compared to the conventional rail section which
are having the value as 72 kg per mm square and that is how it is having a better strength
value. So it can be used at those places where the heavy loads are coming or where the
heavy stressesare getting induced.
Another thing is related to the stresses. In this case 90 UTS rail section provides
allowable shear stressesof the nature of 22.5 kg per mm square.

(Refer Slide Time: 34:08)

Now in the case of 72 UTS rail section the value of allowable shear stressesis 18 kg per
mm square but in the todays condition when we are we are having a sort of box and
wagons being used for the movement of the freight or we are having the heavy loads of
the passenger trafc which are moving in certain directions. In those conditions the
maximum shear stress are reaching to a value of 20 kg per mm square. Therefore, the 72
kg or 70 per mm square or 72 UTS rail section will not be able to take up these type of
stresses

and it is better

to shift

to 90 UTS

rail

section

in this

cases.

Another

characteristic

of 90 UTS rail section is related to its hardness. We are having that hardness due to
higher hardness value the resistancesof the wear are also lesser.
(Refer Slide Time: 35: 10)

The 90 UTS rail section is having hardness number of 270 BHN; this is Brinel Hardness
Number, as you must have studied in the previous years. This is the way of defining the
hardnessbased on the indentation in the metal. So on the basis of that it is giving a value
of 270 as a hardnessnumber whereas in the caseof 72 kg per mm squareUTS rail section
this value is 220 BHN, so it is quite higher as compared to that one.
Then the next step, next value which is of advantageouscondition to 90 UTS rail section
is of its service life. The 90 UTS rail section is having 50 percent higher service life as
compared to conventional 72 kg per mm squareUTS rail section.
(Refer Slide Time: 36:06)

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So this is another aspect which has a long term effect in terms of its maintenance or the
periodicity of the maintenance or the replacement requirements of the rail sections. If we
look it with respect to amount of loading conditions then what we found is that the
service life of 52 kg of 72 UTS section is 350 gross million tones of the load in a year.
Whereas in the case of 90 UTS section with the same of 52 kg per meter rail section it is
525 GMT and if we also change the sectional load of that rail section from 52 kg to 60 kg
per meter and still we are maintaining with the 90 UTS rail section what we found is that
the service life increases to 800 GMT. It means in the previous case it is increasing as
something like one of the half times or in the case of later one it is increasing more than
two

times.

So

this

is

how

the

service

life

has

been

increased

in

the

section

and

therefore

the

maintenance requirements of those will get reduced. It has economical aspect in this
sense. So that is why the 90 UTS section now are of more in use in all those track
conditions where they are heavy loads moving or there are differential loads moving in
different directions. Then they also adaptable for high speed tracks or heavy loads
corridors. They have a lesser wear on curves and gradients with this lesser wear is related
directly to the hardness number as we have seen it has a higher hardness number as
compared to the conventional systems and obviously service life as we have seen

previously is as high as 50 years. Maintenance life is comparable to the life of other
components like concrete sleepers,elastic fastenings etcetera.
(Refer Slide Time: 38: 14)

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yea.
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This is one more aspect here. Now the overall system of track is not of one single
component being provided it is a combination of components. Now when we have a
combination of components then the service requirements or the maintenance
requirement of all those components will be there and if the periodicity or the
maintenance requirement of those all those components are different then it means at one
time we have to take out one component and by doing that the rest of the component also
to be loosened out. Then once it is being done then again the time will come for the
second component, then for the third component. It means again and again we will be
doing the same exercise, whereas if all the component which are being at one place they
are having similar life span then at one point of a time all of them material can be taken
out and can be replaced simultaneously together. So that is what is the more important
optimized and efcient way of doing the maintenance and this is possible in the case of
90 UTS section becauseit has its life which is comparable to other components to which
it is being xed, that is, the concrete sleepersor the elastic fastenings. Now this is one of
the biggest advantagein this case.
Now we come to some of the test we conduct on rail section. The test for grade 710 rails
are falling weight test by which we try to nd out the fatigue condition of that rail
section.

(Refer Slide Time: 39:45)

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The chemical analysis test is to identify the proportion of the chemicals which have been
used; the type of chemicals which have been used in the manufacturing of that rail
section and the tensile test so as to identify the tensile strength of the rail section so that
we can nd out what are the stresseswhich can be taken up by that rail section. In the
caseof 880 rail grade there are some more test other than the falling weight test, chemical
analysis test and tensile test.
(Refer Slide Time: 40:17)

They are microscopic examination where in the microscopic examination helps you to
identify the total causesby which that rail section has been created or manufactured and
if there is any ow in that one then that can be found out. The hardnesstest is to be done
in the case of the ten percent of the casted materials of the rail sections and similarly

there is another test which is termed as the hydrogen content in liquid steel test and this
also to be conducted for liIr1ited cases as five percent of the cast. So these are related to
880 rail grade section.
Now, we come to some sort of the deformations or the defects which may be caused in
the rails.

(Refer Slide Time: 41:19)

There are different types of deformations or defects; one is corrugation, corrugation is the
condition in which at the top surface of the rail section certain irregularities get created.
What we found is that at certain locations the material has come out in the form of small,

very very smaller minute chipping and that is how that irregularity has been created or
there is a wavy pattern that has been created at the top surface of the rail section and this
is what is the corrugation which is being created.
Now as soon as anywhere the link stops moves over these corrugated rail section what is
being observed is that it creates a large amount of noise and because of this reason that
they are creating large amount of noise they are also known as roaring rails ,that is, the
rails which make noise. Another is type of deformation which is being observed is
hogged rails. These hogged rails have being discussed previously too is a peculiar
condition which happens at the joint of the rail sections. At the joint of the rail section
what happensis that becauseof the loosening effect of say the sh plates and the bolts or
becauseof the loosening effect of the ballast cushion which is being provided around the
sleepers below the rail sections, or below the sleepers, or because of the any one levels
which have been provided or which have been created, got created in the rail section.
Whatever means are moving at the top of that one they will strike at one of the rails
whichever is having a higher level. So because of this striking the large impact will be
created and this large impact will start moving the rail section in the downward direction.
So there

is a downward

movement

is what is known as hogged rail.

of the rail

section

at the end of the rail

section

and this

Another case is of a kink in rail. Kink in a rail is a case where wherever the joints are
there the two rail sections goes out of order with each other and that is what is a kink in
rail. It is a sort of a condition where the two lines are being jointed together which are at a
different grades and that is the point of connectivity of these two lines termed as the kink
and this is the type of the thing which happens in the case of rails also if they are not
provided together and they have been jointed using a sh plates and the bolts. So you can
say that it is sort of a relative movement of one rail with respect to another rail in the
lateral direction and creating a kink at that level.
Then buckling of the rail buckling of the rail is related to the effect of the loads which are
coming at the top and due to which the rail goes out of its shape and there is a sort of
widening of the gauge or there is a sort of a reducing of the gauge because of that
buckling of the rail. Damaged rails are the rails which are showing any type of failure
pattern it may be the cracking pattern, it may be the loss of the material or it may be any
other thing which causeswhich can categorize the rail into the failure conditions. So that
what are the sort of damaged rails. We cannot use those rails, we cannot remedify those
rails.

Then they are different type of rail failures. The rail failures may be caused because of
various aspects.We will be looking at all those failures in when we take up in detail the
rail failures as well as the wear on the rails. What type of wear on the rails can be there,
may be on the top of the head, or the side of the rail head, or at the bottom, or what are
the reasonsdue to which those happens and how we can remedify those wears on the rail
failures will be of the next aspect which we take up in some other lecture. Now looking at
all these sort of deformations, or the type of the defects, or the type of the damage
conditions which can be there, we can see some of the things here and this one the
corrugation has been shown. This is the sleeper and this is the rail section which is being
provided here and these are the corrugations which are being shown.
(Refer Slide Time: 45:57)

What we seeis that this wavy pattern which is being causedhere and this is defining this
thing as well as there is a sort of a spouting condition which is created at the top of this
rail section head which will causethe air being filled in this one and as soon as this wheel
moves on this one becauseof this movement of the wheel with respect to this air lled in
there will be noise get created at this one. So, that is why they are also termed as the
roaring wheels
Then this is rail end batter or the battering of the rail or hogging of the condition as we
have discussed. It happens at the end where the two rails have been jointed together. So
what we found is that this is straight profile up to this point and then it is going down like
this.

(Refer Slide Time: 46:33)

So this is what is the battering effect on this side and this is what is the battering effect of
this side. So, once this type of a battering effect has been done now what we have to do
is, we have to loosen out these fish plates and then this have to be dehogged means it has
to be pulled back to the normal conditions so that they become the same level. So that is
the way it is to be done. If it is not possible then it is to be cut out and another section is
to be tted in. Then these are some damaged conditions. Here we can see that the whole
of the piece has come out in this case or in this case, that is, from this side it is breaking
down this is at the end it is breaking down and this is the starting of breaking of this
section from this side or starting of the breaking of the section with respect to the point of
connectivity of this web section with this footed condition and this is the curve of the
llet which will be there at this point.

(Refer Slide Time: 47:24)

So this type of failures can also be there and that is, what is a broken base failure.
Another type of a broken base failure is which where the track is coming through out the
section starting from the head, moving through the web and coming towards the foot.
(Refer Slide Time: 48:08)

So that is how the total rail section has got divided into parts and we cannot use this rail
section. Further, it has to be taken out then there are chances that the material gets
chipped off and when this material is getting chipped off in the form of small layers then
that is termed as aking.

(Refer Slide Time: 48:27)

So here this aking is taking place at this location. Here the location at this location with
what found is that there is a smooth prole as such but at this location slowly and slowly
there is a irregularity and this material in the lay out form is getting chipped. So this is
another type of damage which is getting created to ake rail section and also necessitates
to remove

the rail

section.

Then here we are talking about the piped rail. The piped rail means it is a sort of pipe
condition which gets created as we see in this sectional diagram. This material has gone
away from each other.

(Refer Slide Time: 49:17)

Here what we found is that in the web there is the hole being created in the longitudinal
direction. So in this longitudinal direction this is how it has come out on this side as a
bulging as well as this is also bulging on this side like this. So this gap gets created and
this is what is the pipe being created between the rail where same sort of condition may
happen in this location too.
(Refer Slide Time: 49:50)

Finally, another case is the shelling. Shelling is a further bigger case of aking where in
the case of aking very small particles in the layer form was coming out of whatever is
the section on which that was happening but in this case what we found is a large amount
of material is coming out and when this large amount of material is coming out this is
how it will create a sort of a depression at this top surface and therefore if this top surface
falls towards the side from where the anges will be acting then obviously it is going to
create a big problem. The one way of dealing with these types of conditions is that we
just change the face of the rail section. So if in the initial condition this is the inner side of
the

rail

section

and

what

we

can

do is that

we

can make

this

as outer

side

of the

rail

section and we can just turn this rail like this and the outer side of the rail section will
become

the inner

side

of the rail

section.

In that

case then

we can use the same

rail

still

for some more time period increasing the life of that rail section.
So in these all caseswhat we have seen is that there are different types of defects which
can take place in any of the rail section. So in that sense we have checked in this
particular lecture the various requirements and functions of any of the rail sections. We
have also seen that what are the different types of the rail sections which are available to
us and then on the basis of comparative studies of all those rail section and the historical
background of those we have come up to use the at footed rail sections which are more
advantageous as compared to the other sections. Though there are still some more
problems related to the loosening effects or to the laying and relaying of those systems
and then we have also tried to seethe length, the aspectsrelated to the respecting of those
length, the selection of any of the rail section on the basis of certain factors and then we

have seen the various type of damageswhich are causedin any of the rail section. So we
are we will be closing this particular lecture at this point of time and we will be taking up
another component of the track that is the sleeper in the coming up lecture. So thank you
and bye bye.