Sleepers main

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Present By:-

Shahzad Hashim BSCVL07‐44

Sleepers A railway sleeper, railroad tie (US usage), or railway tie

(Canadian usage) is a rectangular object used as a base

for railroad tracks. Ties are members generally laid

transverse to the rails, on which the rails are supported

and fixed.



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Main function of Sleepers • Holding rails to correct gauge and alignment.

• Firm and even support to rails.

• Transferring the load evenly from rails to

wider area of ballast.

• Elastic medium between rails and ballast.

•Providing

longitudinal

and

lateral

stability.

Types of

sleepers

Types depends upon the position of the sleeper

• Longitudinal sleeper • Cross Sleeper



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Types of sleepers • Depending upon the construction material types of

sleepers are:

Wooden Steel Cast Iron Concrete

Wooden Sleeper

• Wood is ideal material which fulfill all the

requirement of sleeper.

• But due to shortage of wood, it become more

expensive, so we have to search for another

material

•

Wood must

be

well

seasoned

otherwise

its

required treatment.



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Treatment of Wood • Wood contain cell which are fill with the juices

called sap and when this juices dried wood

turn to decay.

• Three method are used for treatment of wood

– Full cell process

– Empty cell process

– No Pressure method



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Pressure Treatmenr.

Care of

Wooden

Sleeper

• Wooden sleeper should be stocked in such a

manner that a free circulation of air all around

and a thin layer of soil is place at the top of the

layer to protect from the direct rays of sun,

shrinkage and cracking.

•

In

order

to

prevent

splitting

of

sleepers

the

spikes

are not driven in one line but are staged.

– Spikes are simply the nails which hold the rail

to the sleeper



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Cont… • Some time ends of sleeper are split so they shoud be

tied with wire.

• For avoiding the crushing of sleeper bearing plates should be interposed between foot of rail and sleeper.

STANDERS FOR WOODEN SLEEPER Sizes

• 9’ x 10” x 5” for BG

• 6’ x 8”

x 4.5”

• 5’ x 7” x 4.5”

Advantages and

Disadvantaged

Advantages: • Easy to manufacture and handling.

• Suitable for track circuited area.

• Can be used with or without ballast.

• Suitable for bridges, Points/Crossings..

• Alignment can be easily corrected.

Disadvantages: • Lesser life.

• Difficult to maintain the gauge.

• Susceptible to fire hazards.



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Life of wooden Sleeper Varies from 10‐12 years and maximum of 20 years and it

depending upon :

• Type of wood used

• Seasoning

• Treatment

• Climate conditions

• Axel loads

• Provision of bearing plated

• Handling conditions

• Location of sleepers

Steel Sleeper

• Steel sleeper are in the form of the shallow

inverted channels with the special fitting to

hold the foot of the rail, the ends of the

sleeper are bend down for stability purpose.



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ST Sleeper

Fittings

• There are two distinct types of fitting in the

steel sleeper:

• Wedges and keys

• Clips and bolt



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Life of Steel Sleeper • Life of steel sleeper is very much greater then

wooden sleeper, life of steel sleeper is lies in 25‐

30 years. But this short life is due to corrosion of

material.so steel sleeper are coated with tar after

manufacture as a protection material.

• Sizes

• Overall length

= 8’

‐9”

• Thickness = 0.25”

Advantages and

Disadvantaged

Advantage: • Steel sleeper keep better alignment of the track.

• The fitting which hold the foot of the rail with sleeper are

more stronger and have lesser tendency to get loose.

• Lateral strength of the track laid with steel sleeper is more.

• Steel sleeper do not much required much maintenance

• Life is greater then wooden sleeper.

Disadvantage: ,

• Steel sleeper should not laid near soil or marshy

area due to corrosion



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Concrete Sleeper • There are two type of reinforced concrete sleepers

Through type • Impact loading causes cracks…

Composite block and tie. • A steel tie or inverted tee section is used and

it

is

not

subjected

to

some

degree

of

tensile

stress so it has gives excellent result.

Cast Iron

Sleepers

Type of Cast Iron Sleepers: A) Pot Sleepers

B) Plate Sleepers

Advantages of Cast Iron Sleepers: i) Lesser corrosion.

ii) Easy handling due to light weight.

iii) Higher

Scrap

value.



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Pot sleeper

Plate Sleeper



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Advantages and Disadvantaged • It can easily manufacture by using locally available material

• Concrete sleeper keeps better alignment of the track.

• Due to heavy weight strength the durability of the track

increase.

• Increase chances of buckling of track minimum.

• Lesser chance of decay and very long life not less then 40 years

• Handling of concrete sleeper is costly and difficult.

• It has no scrap value (No chance of recycle)

• Damage to track are considerable in case of de‐railment.

Disadvantages

• Not suitable for high speed route.

• Difficult to maintain the Gauge.

• Lesser lateral stability.

• Not fit for track circuited area.

• Not suitable for mechanical maintenance.

• Tie bars

weakened

by

corrosion.



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Advantages of concrete Sleepers • Greater stability.

• Track geometry maintained for much.

• Longer duration hence economical.

• No chances of damage by fire/ corrosion

• No possibility of theft.

• No chances

of

gauge

widening.

Disadvantage

• Handling and laying is difficult being heavy.

• Damage is very heavy in case of derailment.

• No scrap value.

• Not suitable for manual packing.



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Sleeper Density • The sleeper density is the number of sleepers used per rail

length.

• Sleeper density depends upon max. permissible speed and

traffic density. axel load and The lateral thrust of locomotives

• let a rail is in yard long and it is provide a sleeper after one

yard so Sleeper density = n

• Sleeper Density = n + x

• N= number

of

yards

in

none

rail

length

• Number of sleeper more then n

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