Component Parts of a Permanent Way

8/17/2019 Component Parts of a Permanent Way

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COMPONENT PARTS OF A PERMANENT WAY

Following are the components of a permanent wav!

"i# S$%gra&e

"ii# 'allast

"iii# Sleepers

"iv# Rails

"v# Fi(t$re an& Fastening

)n a permanent Wa*+ rails are ,oine& either %* wel&ing or %* $sing -sh plates an& are

-(e& with sleepers %* $sing &ifferent t*pes of fastenings! Sleepers are properl* place&

an& pac.e& with %allast! 'allast is place& on the prepare& s$%gra&e calle& formation!

RE/0)REMENTS OF AN )1EA2 PERMANENT WAY

Following are the %asic re3$irements of a permanent Wa*4

"i# The g$age sho$l& %e $niform an& correct!

"ii# 'oth the rails sho$l& %e at the same level in a straight trac.!

"iii# On c$rves proper s$perelevation sho$l& %e provi&e& to the o$ter rail!

"iv# The permanent Wa* sho$l& %e properl* &esigne& so that the loa& of the train is

$niforml* &istri%$te& over the two rails!

"v# The trac. sho$l& have eno$gh lateral strength!

"vi# The ra&ii an& s$perelevation+ provi&e& on c$rves+ sho$l& %e properl* &esigne&!

"vii# The trac. m$st have certain amo$nt of elasticit*!

"viii# All ,oints+ points an& crossings sho$l& %e properl* &esigne&!

"i(# 1rainage s*stem ofpermanent Wa* sho$l& %e perfect!

"(# All the components ofpermanent Wa* sho$l& satisf* the &esign re3$irements!

"(i# )t sho$l& have a&e3$ate provision for eas* renewals an& repairs!

TYPES OF RA)2S

The rails $se& in the constr$ction of railwa* trac. are of following t*pes4

5! 1o$%le hea&e& rails"1!6! Rails#

7! '$ll hea&e& rails"'!6!Rails#

8! Flat foote& rails"F!F!Rails#


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1O0'2E 6EA1E1 RA)2S

The rail sections+ whose foot an& hea& are of same &imensions+ are calle& 1o$%le

hea&e& or

1$m%9%ell rails! )n the %eginning+ these rails were wi&el* $se& in the railwa* trac.!

The i&ea

%ehin& $sing these rails was that when the hea& ha& worn o$t &$e to r$%%ing

action of

wheels+ the rails co$l& %e inverte& an& re$se&! '$t %* e(perience it was fo$n& that

their foot

co$l& not %e $se& as r$nning s$rface %eca$se it also got corr$gate& $n&er the impact

of wheel

loa&s! This t*pe of rail is not in $se in )n&ian Railwa*s now9a &a*s! Fig!

:!5 shows &o$%le hea&e& rail!

'022 6EA1E1 RA)2S

The rail section whose hea& &imensions are more than that of their foot are calle& %$ll

hea&e&

rails! )n this t*pe of rail the hea& is ma&e little thic.er an& stronger than the lower part

%*

a&&ing more metal to it! These rails also re3$ire chairs for hol&ing them in

position! '$ll

hea&e& rails are especiall* $se& for ma.ing points an& crossings!

MER)TS

"i# '!6! Rails .eep %etter alignment an& provi&e more smoother an& stronger trac.!

"ii# These rails provi&e longer life to woo&en sleepers an& greater sta%ilit* to

the

trac.!

"iii# These rails are easil* remove& from sleepers an& hence renewal of trac. is eas*!

1EMER)TS

"i# '!6! rails re3$ire a&&itional cost of iron chairs!

"ii# These rails re3$ire heav* maintenance cost!


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"iii# '!6! rails are of less strength an& stiffness!

F2AT FOOTE1 RA)2S

The rail sections having their foot rolle& to flat are calle& flat foote& or vignole;s rails!

This

t*pe of rail was invente& %* Charles ! )t was initiall* tho$ght that

the flat

foote& rails co$l& %* fi(e& &irectl* to woo&en sleepers an& wo$l& eliminate chairs an&

.e*s

re3$ire& for the '!6! rails! '$t later on+ it was o%serve& that heav* train loa&s ca$se&the foot

of the rail to sin. into the sleepers an& ma.ing the spi.es loose! To remove this &efect+

steel

%earing plates were $se& in %etween flat foote& rails an& the woo&en sleeper! These

rails are

most commonl* $se& in )n&ia! Fig!:!8 shows flat foote& rail!

MER)TS

"i# F!F! rails have more strength an& stiffness!

"ii# No chairs are re3$ire& for hol&ing them in position!

"iii# These rails re3$ire less n$m%er of fastenings!

"iv# The maintenance cost of trac. forme& with F!F! rails is less!

1EMER)TS

"i# The fittings get loosene& more fre3$entl*!

"ii# These rails are not easil* remove& an& hence renewal of trac. %ecomes

&iffic$lt!

"iii# )t is &iffic$lt to man$fact$re points an& crossings %* $sing these rails!


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RA)2WAY EN?)NEER)N? 1ept! of Civil Engineering 9 @20

'!?!Rah$l

S2EEPERS

Sleepers are transverse mem%ers of the trac. place& %elos the rails to s$pport an& fi(

them in

position!

F0NCT)ONS OF S2EEPERS

Sleepers serve the following f$nctions4

"i# To hol& the rails to proper ga$ge!

"ii# To transfer the loa&s from rails to the %allast!

"iii# To s$pport an& fi( the rails in proper position!

"iv# To .eep the rails at a proper level in straight trac.s an& at proper s$per

elevation on c$rves!

"v# To provi&e elastic me&i$m %etween the rails an& the %allast!

"vi# To provi&e sta%ilit* to the permanent wa* on the whole!

RE/0)REMENTS OF ?OO1 S2EEPERS

The following are the re3$irements of goo& sleepers4

"i# The sleepers sho$l& %e s$fficientl* strong to act as a %eam $n&er loa&s!"ii# The sleepers sho$l& %e economical!

"iii# The* sho$l& maintain correct g$age!

"iv# The* sho$l& provi&e s$fficient %earing area for the rail!

"v# The sleepers sho$l& have s$fficient weight for sta%ilit*!

"vi# Sleepers sho$l& facilitate eas* fi(ing an& ta.ing o$t of rails witho$t &ist$r%ing

them!

"vii# The* sho$l& facilitate eas* removal an& replacement of %allast!


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"viii# The* sho$l& not %e p$she& o$t easil* of their position in an* &irection $n&er

ma(im$m forces of the moving trains!

"i(# The* sho$l& %e a%le to resist impact an& vi%rations of moving trains!

"(# The* sho$l& %e s$ita%le to each t*pe of %allast!

"(i# )f trac.9circ$iting is &one+ it sho$l& %e possi%le to ins$late them from the rails!

TYPES OF S2EEPERS

Sleepers are of the following t*pes4

5! Woo&en sleepers!

7! Steel sleepers!

8! Cast iron sleepers!

:! R!C!C! sleepers!

! Priestesses concrete sleepers!


'!?!Rah$l

5! Woo&en Sleepers4 These sleepers are regar&e& to %e the %est as the* satisf*

all the

re3$irements of goo& sleepers an& are the onl* sleeper s$ita%le for trac.

circ$iting!

The life of woo&en sleepers &epen&s $pon their a%ilit* to resist wear+ attac. %* white

ants an&

3$alit* of tim%er $se&! Tim%ers commonl* $se& in )n&ia for sleepers are sal+ Tea.+

1eo&ar

an& chair woo&!

The stan&ar& siBes of woo&en sleepers for &ifferent ga$ges are as follows4

For '!?! 7D: mm 7 mm 58 mm

For MG !?! 5=8 mm 78 mm 55: mm

For N!?! 57 mm 5 mm 5 mm


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'!?!Rah$l

2$gs are forme& %* pressing o$t the metal of the channel section loose ,aw

t*pe is an

improvement on presse& l$g t*pe! Fig!!7 shows .e* t*pe steel sleepers!

"%#Clip an& %olt t*pe steel sleepers4 )n this t*pe of sleeper+ clips an& %olts are

$se& for

hol&ing the rails as shown in Fig!!8! Crac.s are not &evelope& in the sleepers as the

holes for

the %olts are small an& circ$lar! )t re3$ires fo$r clips an& fo$r %olts for hol&ing eachrail!

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)n&ia as compare& to other co$ntries in the worl&! Cast iron sleepers are of the

following

t*pes4

"i# Pot or %owl sleeper

"ii# Plate sleeper

"iii# 'o( sleeper

"iv# CST9H sleeper

"v# 1$ple( sleeper

"i# Pot or %owl sleeper4 Pot sleeper consist of two %owls place& $n&er each

rail an&

connecte& together %* a tie9%ar! The total effective area of %oth the pots is !:>: s3!

m! Each

pot is provi&e& with two holes foe inspection an& pac.ing of %allast! On the top of

each pot+ a

rail seat is provi&e& to hol& rails at an inwar& slope of 5 in 7! ?i%s an& cotters are so

caste&

that %* interchanging them ga$ge is slac.ene& %* 8 mm!


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"ii# Plate sleeper4 Plate sleepers consists of two rectang$lar plates of =>: mm 8

mm in

siBe with short si&e parallel to rail! The plates are provi&e& with pro,ecting ri%s in the

%ottom

to provi&e a grip in the %allast for lateral sta%ilit*! The plates are hel& in position %*

tie9%ar!

Stiffners are provi&e& at the top of the plate to increase the strength! For

mi(ing of rails

s$ita%le arrangement is &one as shown in Fig!!>! )t provi&es the effective %earing

area of


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!:>:s3! m per sleeper!

"iii# 'o( Sleeper4 These sleepers are not in $ser these &a*s! 'o( sleepers are similar

to plate

sleepers! )n this t*pe of sleeper+ a %o( is provi&e& at the top of each plate to hol& the

rails!

"iv# CST9H Sleeper4 CST9H sleeper is more satisfactor* than other C!)!

Sleepers an& is

e(tensivel* $se& in )n&ian Railwa*s since last thirt* *ears! )t is a com%ination of pot+ plate+

an& %o( sleeper! CST9Hs sleeper consists of a triang$lar inverte& pot one on each si&e

of rail

seat! Rail seat is provi&e& at the top to hol& rails at 5 in 7 inwar& slope!

The pots are

connecte& across the trac. %* means of a tie9 %ar! Fig!!D shows CST9H sleeper!

"v# 1$ple( Sleepers4 1$ple( sleepers are also .nown as rail free &$ple( sleepers an&

have

%een $se& at rail ,oints in con,$nction with CSTH sleepers! These sleepers are $se& at

rail

,oints to prevent cantilever action %etween two s$pports of the CST9H sleepers! These

consists

of two plates+ each of siBe = mm D mm! The plates are place& with the longer

si&e

parallel to the rails an& are connecte& with a tie9%ar! Fig!!= shows &$ple( sleepers!

A&vantages of C!) sleepers are more!

"i# The life of C!) sleepers is more!

"ii# The maintenance cost of these sleepers is low!

"iii# ?$age can %e easil* maintaine& an& a&,$ste& with these sleepers!

"iv# These sleepers are more &$ra%le!


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"v# Creep rails can %e chec.e& %* $sing these sleepers!

1isa&vantages

"i# More %allast is re3$ire& than an* other t*pe of sleepers!

"ii# The n$m%er of fittings re3$ire& is more!

"iii# These sleepers are lia%le to %rea.!

"iv# C!)! Sleepers are lia%le to %rea.!

"v# These are not s$ita%le for all t*pes of %allast!

:! R!C!C! Sleepers4

Reinforce& cement concrete sleepers are of two t*pes4

"i# Thro$gh t*pe

"ii# 'loc. an& tie t*pe


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"i#Thro$gh t*pe R!C!C! Sleeper4 This is also .nown as one piece or mono9

%loc.

sleeper! )n this t*pe of sleeper crac.s &evelop on the tension si&e when stresse&! These

crac.s

are ver* small an& almost invisi%le %$t ten& to enlarge with the repetition of impact

loa&ing+

ca$sing fail$re!

"ii#'loc. an& tie t*pe R!C!C! Sleeper4 This t*pe of sleeper consists of two

R!C!C!

%loc.s connecte& %* a metal tie of inverte& T9section! These sleepers are not s$%,ecte&

to an*

&egree of tensile stress as in thro$gh t*pe!

A&vantages of R!C!C! Sleepers

"i# Concrete sleepers have long life+ generall* :to > *ears!


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"ii# These are free from nat$ral &eca* an& attac. %* insects etc!

"iv# These sleepers re3$ire less fittings!

"v# Trac. circ$iting is possi%le in these sleepers!

"vi# These sleepers provi&e more lateral an& longit$&inal rigi&it* as compare& to

other sleepers!

"vii# The maintenance cost is low!

"viii# 1$e to higher elastic mo&$l$s+ these can withstan& the stresses &$e to

fast

moving trains!

1isa&vantages

"i# 1$e to heav* weight+ han&ling an& transportation of these sleepers are

1iffic$lt!

"ii# )f not han&le& properl*+ the chance of %rea.ing is more!

"iii# The renewal of trac. lai& with these sleepers is &iffic$lt!

"iv# The scrap val$e is nil!

! Prestresse& Concrete Sleepers4

Prestresse& concrete sleepers are now9a9&a*s e(tensivel* $se& in )n&ian

Railwa*s! These

sleepers have high initial cost %$t are ver* cheap in long r$n &$e to their long life! )n

these

sleepers+ high tension steel wires are $se&! These wires are stretche& %* h*&ra$lic ,ac. to give

necessar* tension in the wires! The concrete is then p$t $n&er a ver* high initial

compression!

These sleepers are heavil* &amage& in caser of &erailment or acci&ents of trains!



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'!?!Rah$l

'A22AST

'allast is the gran$lar material $s$all* %ro.en stone or an* other s$ita%le material

which is

sprea& on the top of railwa* formation an& aro$n& the sleepers!

F0NCT)ONS OF 'A22AST

'allast in railwa* trac. performs the following f$nctions!

"i# To hol& the sleepers in position an& preventing the lateral an& longit$&inal

movement!

"ii# To &istri%$te the a(le loa& $niform from sleepers to a large area of formation!

"iii# To provi&e elasticit* to the trac.! )t acts as as elastic mat %etween s$%gra&e

an& sleepers!

"iv# To provi&e eas* means of maintaining the correct levels of the two rails in a

trac.!

"v# To &rain rain water from the trac.!

"vi# To prevent the growth of wee&s insi&e the trac.!!

C6ARACTER)ST)CS OF ?OO1 'A22AST

"i# )t sho$l& have s$fficient strength to resist cr$shing $n&er heav* loa&s of

moving trains!

"ii# )t sho$l& %e &$ra%le eno$gh to resist a%rasion an& weathering action!"iii# )t sho$l& have ro$gh an& ang$lar s$rface so as to provi&e goo& lateral

an&

longit$&inal sta%ilit* to the sleepers!

"iv# )t sho$l& have goo& wor.a%ilit* so that it can %e easil* sprea& of formation!

"v# )t sho$l& %e cheapl* availa%le in s$fficient 3$antit* near an& along the trac.!

"vi# )t sho$l& not ma.e the trac. &$st* or m$&&* &$e to its cr$shing to

pow&er

$n&er wheel loa&s!


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%! )t has ang$lar an& ro$gh s$rface an& hence gives more sta%ilit* to the

sleepers!

c! )ts &rainage propert* is e(cellent!

1)SA1


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"%# ?ravel o%taine& from pits re3$ires washing!

"c# 1$e to ro$n& faces the pac.ing $n&er sleepers is loose!

" ?ravel easil* roll &own &$e to vi%rations!

"iii#SAN14

San& is reasona%l* a goo& material for the %allast! Coarse san& is generall* preferre&

to fine

san& for %allast! This t*pe of %allast is s$ita%le for pac.ing pot sleepers! )t is $se& onl*

on

$nimportant trac.s!

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"v#@AN@AR4 )t is nat$ral material in the form of no&$les from which lime is

prepare&!

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"%# )t has goo& &rainage properties!

"c# )t is a strong material!

" )t hol&s the trac. in correct alignment an& gra&ient!

1)SA1


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%* sin.ing into soft formation!


'!?!Rah$l

F)T0RES AN1 FASTEN)N?S

F)T0RES AN1 FASTEN)N?S

Fi(t$res an& fastenings are fittings re3$ires for ,oining of rails en& to en& an& also forfi(ing

the rails to sleepers in a trac.!

F0NCT)ONS OF F)T0RES AN1 FASTEN)N?S

Rail fi(t$res an& fastenings have the following f$nctions4

"i# To ,oin the rails en& to en& to form f$ll length of trac.!

"ii# To fi( the rails to sleepers!

"iii# To maintain the correct alignment of the trac.!


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"iv# To provi&e proper e(pansion gap %etween rails!

"v# To maintain the re3$ire& tilt of rails!

"vi# To set the points an& crossings in proper position!

TYPES OF F)T0RES AN1 FASTEN)N?

Fi(t$res an& fastenings commonl* $se& in a permanent wa* are of following t*pes4

5! Fish plates

7! 'earing plates

8! Spi.es

:! Chairs

! 'olts

>! @e*s

D! Anticreepers

F)S6 P2ATES

Fish plates are $se& in rail ,oints to maintain the contin$it* of the rails! Two t*pes of

fish

plates are commonl* $se& on )n&ian Railwa*s for ,oining F!F! an& '!6! rails+ as

shown in

Fig!D!5! each fish plate is :D mm long an& provi&e& with fo$r holes 87 mm

at a spacing of

55: mm cIc! These are man$fact$re& of steel an& are so &esigne& that the* fit in

%etween the

hea& an& foot of the rail!

RE/0)REMENTS OF F)S6 P2ATES

"i# The* sho$l& hol& the a&,oining en&s of rails in correct horiBontal an&

vertical plane!

"ii# The* sho$l& allow free longit$&inal movements of rails &$e to

temperat$re variation!

"iii# The* sho$l& %e a%le to resist all t*pes of wear!


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"iv# The* sho$l& %e a%le to %ear the vertical an& lateral stresses which

come at ,oints witho$t an* &istortion!

"v# The* sho$l& allow eas* renewal an& replacement of rails in case of

wear an& &amage!


'!?!Rah$l

!'EAR)N? P2ATES

'earing plates are cast iron or steel plates place& in %etween the F!F rail an& woo&ensleepers

of a railwa* trac.! F!F! rails if fi(e& &irectl* on woo&en sleepers sin. in the sleeper

&$e to the

heav* loa&s of trains an& th$s loosen the spi.es! To overcome this &iffic$lt* %earing

plates

are $se& $n&er F!F! rails to &istri%$te the loa& over a wi&er area an& %ring the intensit*

of

press$re within limit!

'earing plates give the re3$ire& 5 in 7 inwar& slope to the rail &irectl* an& no

a&BingJ is

re3$ire& in the woo&en sleeper! These are fi(e& to sleepers %* spi.es!

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Following are the &isa&vantages of %earing plates4

"i# When the %earing plates %ecome loose &$e to settlement of %allast+

moist$re is li.el* to enter %etween the sleepers an& plates+ ca$sing

sleepers to wear!

"ii# When an* spi.e is &amage& an& it is re3$ire& to %e re&riven at another

place+ all other spi.es of the %earing plates have to %e remove&+ which will

re&$ce the hol&ing power of the spi.es!

SP)@ES

Spi.es are $se& to fi( rails to woo&en sleepers! Spi.es are of following t*pes4

"a# 1og spi.es

"%# Ro$n& spi.es

"c# Screw spi.es

" Elastic spi.es

1og spi.es are the cheaper t*pe of spi.es which hol& the rails at correct ga$ge

an& can %e easil* fi(e& an& remove&! These are commonl* $se& for hol&ing F!F! rails!

Fo$r

&og spi.es are $se& per sleeper+ two on either si&e of the rail! The &isa&vantage of &og

spi.es

is that these %ecome loose $n&er the wave action ca$se& %* the moving train!


'!?!Rah$l

Ro$n& spi.es are $se& for fi(ing chairs of '!6! rails to woo&en sleepers an& also for

fi(ing sli&e chairs of points an& crossings! These have either c*lin&rical or

hemispherical

hea& an& %l$nt en&!

Screw spi.es are tapere& screws with


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&og spi.es!

Elastic spi.es are $se& for fi(ing F!F! rails to woo&en sleepers! These give %etter grip

an& res$lt in re&$ction of wear an& tear of rail! The a&vantage of this t*pe of spi.e is

that it is

not p$lle& $p %* the wave action of the moving train!

RE/0)REMENTS OS A ?OO1 SP)@E

"i# )t sho$l& %e eas* in fi(ing or removing from the sleepers!

"ii# )t sho$l& hol& the rails an& %earing plates in proper position!

"iii# )t sho$l& %e cheap!

"iv# )t sho$l& re3$ire minim$m maintenance!

"v# )t sho$l& not come o$t of the sleepers $n&er vi%rations!

'O2TS

&ifferent t*pes of %olts $se& in )n&ian Railwa* are &escri%e& %elow!

F)S6 'O2TS

Fish %olts are $se& for connecting fish plates with the rails! Fo$r %olts are re3$ire& for

each

pair of fish plates! These %olts are inserte& from o$tsi&e the trac. an& %olte& on the

insi&e of

the trac.!

Fish %olts have to withstan& shear &$e to heav* transverse stresses+ hence the*

are

man$fact$re& of me&i$m or high car%on steel! The length of fish %olt &epen&s on the

t*pe of

fish plate $se&! For ::!D.g rail+ the fish %olts of 7 mm &ia an& 57D!> mm length are

$se&!

These %olts get loosene& &$e to vi%ration of moving train an& hence these are to %e

tightene&

time ot time! Too m$ch tightening of %olts is prohi%ite& as it prevents free

e(pansion or

contraction of rails &$e to temperat$re vi%rations!

6OO@ 'O2TS


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6oo. %olts are also .nown as &og %olts &$e to the shape of their hea&s! These %olts

are $se&

to fi( sleepers which rest &irectl* on a gir&er! Two %olts per sleeper are $se&! 1og

%olts are of

two t*pes!

"i# Sloping lips9 for fi(ing sleepers to plate gir&er spans!

"ii# Straight lips9 for fi(ing sleepers to ,oist spans!


'!?!Rah$l

FAN? 'O2TS

Fang %olts are $se& for fi(ing si&e chairs to sleepers! These are alternative to screw or

ro$n&

spi.es! The fang %olts are fo$n& to %e more effective %$t are not generall*

$se&+ %eca$se

fi(ing an& removal of these %olts are &iffic$lt!

@EYS

These are small tapere& pieces of tim%er or steel $se& to fi( rails to chairs on metal

sleepers!

@e*s are of two t*pes

"i# woo&en .e*s

"ii# Metal .e*s

Woo&en .e*s are small straight or tapere& pieces of tim%er! These are cheap

an& Easil*

prepare&! These are not strong an& %ecome loose $n&er vi%rations! These

re3$ire fre3$ent

maintenance! Woo&en .e*s are not $se& now9a &a*s in )n&ian Railwa*s!

Metal .e*s are small tapere& or spring li.e pieces of steel! These .e*s are m$ch more

&$ra%le

than woo&en .e*s! Metal .e*s are of two t*pes!

"i# St$art;s .e* an&

"ii# Morgan .e*


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ANT)9CREEPERS

Anti9creepers are $se& to prevent creep in a railwa* trac.! 1ifferent shapes of anti9

creepers

are availa%le an& are fi(e& to the foot of rail! )t is shown in Fig!:!5!


'!?!Rah$l

?RA1)ENT

?ra&ient is the rate of rise or fall of the trac.! )t is e(presse& as the ratio of vertical

&istance

to horiBontal &istance or as percentage of rise or fall! )f an* trac. rises 5 m

in 5 m

horiBontal length+ its gra&ient is e(presse& as 5 in 5 or 5 percent! )f another trac.

falls %* 5

m in m length+ its gra&ient is 5 in or 7 percent!

?ra&ients are provi&e& to the formation of rail trac. to serve the following p$rpose4

"i# To re&$ce the cost of earthwor.!

"ii# To provi&e $niform rate or fall as far as practica%le!

"iii# To reach the stations sit$ate& at &ifferent elevations!


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"iv# To &rain off rain water!

Factors which affect the selection of gra&ient are the following4

"i# Nat$re of the gro$n&

"ii# Safet* re3$ire&

"iii# 1rainage re3$ire&

"iv# Total height to %e covere&

"v# 6a$ling capacit* of railwa* engines!

T*pes of gra&ient

"i# R$ling gra&ient

"ii# Moment$m gra&ient

"iii# P$sher gra&ient

"iv# Station *ar& gra&ient

"i# R$ling ?ra&ient4 R$ling gra&ient is the ma(im$m gra&ient to which the trac. ma*

%e lai& in a partic$lar section! )t &epen&s on the loa& of the train an& a&&itional

power of the locomotive! The a&&itional power re3$ire& to p$ll $p a train of

weight W moving in a trac. having slope

+ as shown in fig! =!7+ is

F K W sin

K W tan

K W ( gra&ient

From the a%ove e3$ation it is clear that the a&&itional power re3$ire& %* the

locomotive train+

the following r$ling gra&ients are a&opte&4



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'!?!Rah$l

)n plains 9 5 in 5 to 5 in 7

)n 6ill* trac.s 9 5 in 5 to 5 in 5

"ii# Moment$m ?ra&ient 4 gra&ient which is steeper than r$ling gra&ient an& where

the a&vantage of moment$m is $tiliBe&+ is .nown as moment$m gra&ient! A train

gets moment$m when moving in &own gra&ient an& this moment$m can %e

$tiliBe& for $p gra&ient! A train while coming &own a gra&ient gains s$fficient

moment$m! This moment$m gives a&&itional .inetic energ* to the moving train

which wo$l& help the train to rise a steeper gra&ient than the r$ling gra&ient for a

certain length of the trac.! This rising gra&ient is calle& moment$m gra&ient! )n

s$ch gra&ients no signals are provi&e& to stop the train!

"iii# P$sher ?ra&ient4 P$sher gra&ient is the gra&ient where e(tra engine is re3$ire& to

p$sh the train! These are steeper gra&ient than r$ling gra&ient an& are provi&e& at

certain places of mo$ntains to avoi& heav* c$tting or to re&$ce the length of trac.!

A p$sher gra&ient of 5 in 8D on western ?hats with '!?!trac. is provi&e&! On

1ar,eeling Railwa* with N!?! trac.+ a r$ling gra&ient of 5 in 7 is provi&e&!L

"iv# Station Yar& ?ra&ient4 Station *ar& gra&ient is the minim$m gra&ient provi&e& in

station *ar& for eas* &raining of rain water! ?ra&ients are avoi&e& as far as

possi%le in station *ar& &$e to following reasons

"a# )n station *ar&+ 'ogies stan&ing on gra&ients ma* start moving &$e to heav*

win& an& ma* ca$se acci&ent!

"%# The locomotives will re3$ire e(tra force of p$ll the train on gra&ients at the

time of starting the trains!


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)n station *ar&s+ ma(im$m limit of gra&ient is fi(e& as 5 in : an&

minim$m gra&ient

recommen&e& is 5 in 5 for eas* &rainage of rain water!


'!?!Rah$l

?RA1E COMPENSAT)ON OF C0R


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'!?!Rah$l

S0PERE2E


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horiBontal force an& $neven loa& on rails will ca$se &erailment! This centrif$gal force

can %e

co$nteracte& %* intro&$cing the centripetal force %* raising the o$ter rail with respect

to inner

rail! This raising of o$ter rail with respect to inner rail is .nown as

s$perelevation or

canting!

O%,ects of Provi&ing S$perelevation

The following are the o%,ects of provi&ing s$perelevation4

"i# To intro&$ce centripetal force to co$nteract the centrif$gal force to avoi&

&erailment an& re&$ce the si&e wear of rails!

"ii# To &istri%$te the wheel loa&s e3$all* on the two rails! This re&$ces the top wear

of

rails an& res$lts in saving of maintenance cost!

"iii# To ens$re comforta%le ri&e to passengers an& safe movements of goo&s!



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'!?!Rah$l

CANT 1EF)C)ENCY

Cant &eficienc* is the &ifference %etween the act$al cant provi&e& an&

e3$ili%ri$m cant

necessar* for the ma(im$m permissi%le spee& on a c$rve!

Cant &eficienc* sho$l& %e as low as possi%le an& is limite& &$e to following reasons4

"a# 6igher &iscomfort to passengers &$e to higher cant &eficienc*

"%# 6igher cant &eficienc* res$lts in higher $n%alance& centrif$gal force an& hence

e(tra

press$re an& lateral thr$st on the o$ter rails+ re3$iring strong trac. an& more fastening

for sta%ilit*!

"c# Si&e wear an& creep of o$ter rails of the trac. are more &$e to higher cant

&eficienc*!

Ma(im$m val$es of cant &eficienc* as prescri%e& on )n&ian Railwa*s are given in

Ta%le

2imits of cant &eficienc* for &ifferent ga$ges on )n&ian Railwa*s

S!No! ?a$ge

Cant 1eficienc*

For spee&s

0pto 5 .mIhr

For spee&s higher

Than 5 .mIhr

5!

7!

8!

'!?

M!?!

N!?!


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D> mm

5 mm

8= mm

5 mm

Not specifie&

9&o9

NE?AT)


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'!?!Rah$l

T0RNO0T

T$rno$t is an arrangement of points an& crossings with lea& rails %* which trains ma*

%e

&iverte& from one trac. to another moving in the facing &irection

A t$rno$t is left han&e& or right han&e& as the train ta.ing the t$rno$t in the facing

&irection

is &iverte& ti the left or right of the main line!

Component parts of a T$rno$t an& their F$nctions

Following are the component parts of a t$rno$t

"i# A pair of tong$e rails

"ii# A pair of stoc. rails

"iii# Two chec. rails

"iv# Fo$r lea& rails

"v# A vee crossing

"vi# Sli&e chairs

"vii# Stretcher %ar

"viii# A pair of heel %loc.s

"i(# Switch tie plate or ga$ge tie chair

"(# Parts for operating points Ro&s+ cran.s+ levers etc!

"(i# 2oc.ing s*stem which incl$&es loc.ing %o(+ loc. %ar+ pl$nger %ar etc!

"(ii#

"i# A Pair of Tong$e Rails4 The tong$e rails along the stoc. rails in a t$rno$t form a

pair of points or switches! The tong$e rails facilitate the &iversion of a train from

the main trac. to a %ranch trac.!

"ii# A Pair of Stoc. Rails4 The* are the main rails to which the tong$e rails fit closel*!

The stoc. rails help in smooth wor.ing of tong$e rails!

"iii# Two Chec. Rails4 Chec. rails are provi&e& a&,acent to the lea& rails+ one in main

trac. an& another in %ranch trac.! These rails chec. the ten&enc* of wheels to

clim% over the crossing!


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"iv# Fo$r 2ea& Rails4 O$ter straight lea& rail+ o$ter c$rve lea& rail+ inner straight lea&

rail an& inner c$rve lea& rail are the fo$r lea& rails provi&e& in a t$rno$t! The

f$nction of these rails is to lea& the trac. from heel of switches to the toe of

crossing!

"v# A


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'!?!Rah$l

CROSS)N?

Crossing is a &evice provi&e& at the intersection of two r$nning rails to permit

the wheelflanges+ moving along one to pass across the other!

Component Parts of a Crossing

"i# A vee piece

"ii# A point rail

"iii# A splice rail

"iv# Two chec. rails

"v# Two wing rails


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"vi# 6eel %loc.s at throat+ nose an& heel of crossing

"vii# Chairs at crossing+ at toe an& at heel!

RE/0)REMENTS OF )1EA2 CROSS)N?

"i# Crossing assem%l* sho$l& %e rigi& eno$gh to withstan& severe vi%rations!

"ii# Wing rails an& nose of crossing sho$l& %e a%le to resist heav* wear &$e

to

movement of wheels+ hence sho$l& %e man$fact$re& of special steel "allo* steel#!

"iii# The nose of crossing sho$l& have a&e3$ate thic.ness to ta.e all stresses acting on

the crossing!

TYPES OF CROSS)N?S

Crossings can %e classifie& as follows4

5! On the %asis of shape of crossing

"a# S3$are crossing

"%# Ac$te angle or


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Documents

Component Parts of a Permanent Way