sleepers & fittings

Sleepers

and fastenings

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.

Laying of Sleepers

• Sleepers shall be laid square to rails on straight and radially on curve.

• The sleeper spacing should be marked on outer rail in case of curved track.

• Closer spacing should be provided at joint sleepers of fish plated joints and between joint sleeper and shoulder sleeper.

• Rail joints should be suspended.

Suspended Joint

Sleeper density

• The sleeper density is the number of sleepers used per rail length.

• Described as M+1, M+2, M+3 etc. Where M is the length of standard rail in meters.

• In case of LWR/CWR, this is expressed in number of sleeper per Km of track.

• Sleeper density depends upon max. permissible speed and traffic density.

Types of Sleepers

Wooden Sleepers

Cast Iron Sleepers

Steel Sleepers

Concrete Sleepers

Wooden Sleepers

Classification of wooden sleepers

• Untreated Sleeper – ‘U’

• Treated Sleeper – ‘T’

Advantages/Disadvantages of wooden Sleepers

Advantages

i) Easy to manufacture and handling.

ii) Suitable for track circuited area.

iii) Can be used with or without ballast.

iv) Suitable for bridges, Points/Crossings.

v) Suitable for gaunteletted track.

vi) Alignment can be easily corrected.

Contd. …

Disadvantages:

i) Lesser life.

ii) Liable to damage by beater packing.

iii) Difficult to maintain the gauge.

iv) Susceptible to fire hazards.

Description of Wooden Sleepers

Size of wooden sleepers in mm :

B.G. : For ordinary track 2750x250x130 (9’x10”x5”)

Durable and non durable types of sleepers.

Life of Sleeper:

Durable –19 years (B.G.)/ 31 years (M.G.)

Non-Durable- 12 to16 years.

• Adzing of wooden sleeper

• End Binding of sleepers

• Stacking of sleepers

• Auguring of sleeper – T and U category

• Fixing of screw spike

• Dating

Number of Screw/Spike per Rail seat

Joint sleepers, Bridge timbers turn out sleepers

Four

Intermediate sleepers on curves on other than branch lines

Three

Intermediate sleepers on curve on branch lines and on straight

Two

Canted Bearing plate

Use of Bearing Plates

• ‘T’ Category sleepers

• Girder Bridges

• Turn outs

• Ash pits and examination pits

• On sharp curve of radius less than 600 m on B.G. and M.G.

Cast Iron Sleepers

Cast Iron Sleepers

Type of Cast Iron Sleepers: A) C. I. Pot Sleepers B) C S T- 9 Sleepers Advantages of Cast Iron Sleepers: i) Lesser corrosion. ii) Easy handling due to light weight. iii) Higher Scrap value.

Pot sleeper

CST-9 Sleeper

Contd. …

Disadvantages of Cast Iron Sleepers:

i) Not suitable for high speed route.

ii) Difficult to maintain the Gauge.

iii) Lesser lateral stability.

iv) Not fit for track circuited area.

v) Not suitable for mechanical maintenance.

vi) Tie bars weakened by corrosion.

Usual defects in CST-9 Sleepers

• Cracks at rail seats or fracture

• Wear of lug and rail seat

• Tie bars weakened by corrosion, broken or damaged by falling of wagon parts.

• Corrosion of tie bars inside the cast iron plates.

ST Sleeper

Steel trough Sleepers

Types of S.T. Sleepers

i) ST sleepers with Pressed up lugs.

ii) ST Sleepers with loose jaws.

iii) Bolt and clip type ST Sleepers.

iv) Special ST Sleepers for Turn out.

v) ST Sleepers with pad plates for use with elastic rail clip.

ST Sleeper with pressed up lug

ST Sleepers with loose jaws

Contd. …

Advantages of ST Sleepers:

i) Longer life

ii) Better Stability

iii) Lesser damage during handling /Transport

iv) Easy to maintain Gauge

v) Simple Manufacturing Process

vi) High Scrap value

Contd. …

Disadvantages of ST Sleepers: i) Liable for corrosion. ii) Not fit for track circuited area. iii) Develops cracks at rail seat during

service. iv) Can only be used for rails for which it is

manufactured.

Usual defects in ST Sleepers

• Rusted and corroded metal

• Cracks at rail seat or near the lugs

• Elongation of holes

Inspection of sleepers- Over 20 years old

Precautions during maintenance

Reconditioning of sleeper

Concrete Sleepers

Concrete Sleepers & Fastenings

Types of concrete Sleepers:

i)Mono-block Prestressed Concrete Sleepers.

a) PSC-12 for 52 Kg Rails

b) PSC-14 for 60 Kg Rails

ii) Two block reinforced concrete Sleepers.

Contd. …

Main features of PSC-12/PSC-14 Sleepers:

Length : 2750 mm

Weight : 267 Kg

Reinforcement : 18 number 3mm dia HTS stands

Dist bet. Insert at rail seat :148mm/162 mm

Service Life : 50 to 60 years.

Contd. …

Advantages of concrete Sleepers:

i) Greater stability.

ii) Track geometry maintained for much. longer duration hence economical.

iii) Best suited for machine maintenance.

iv) Suitable for Track circuiting area.

Contd. …

v) No chances of damage by fire/ corrosion

vi) No possibility of theft.

vii) No chances of gauge widening.

viii) 60 Kg Sleeper can be used for 52 Kg rail.

ix) Best suited for LWR track.

x) Best performance on P & C, S.E.J. Guard rails , Level Crossings, Check rail in curve.

Contd. …

Disadvantage :

i) Handling and laying is difficult being heavy.

ii) Damage is very heavy in case of derailment.

iii) No scrap value.

iv) Not suitable for manual packing.

Contd. …

Conditions for laying Concrete Sleepers:

i) Track should be deep screened.

ii) Cuttings having rocky bed should have clean ballast cushion of at least 300 mm.

iii)On Arch bridges formation cover min. 1 m.

iv) On other bridges ballast cushion not less than 300 mm.

Elastic Fastenings

Grooved rubber pads:• Provided between rails and sleepers.• It absorbs the shock.• Resists lateral movement of the rail.• Prevents abrasion of the bottom surface of

rail.• Laid in such a way that grooves are parallel

to rail .

Elastic Rail clip (Pandrol Clip)

• Fixed in Insert to hold the rail.

• Made from Spring Steel bar of 20.6 mm.

• Toe Load 900Kg to 1100 Kg (MKIII).

• On Fish plated Joint ‘J’ Clip can be used.

• Can be driven with ordinary 4 lbs hammer.

• Can be fixed on wooden,Steel, and Cast Iron Sleepers with Special arrangement.

Contd. …

Liners :

i) Metal Liners – Provided on Non track circuited Areas.

ii) Insulated Liners- Provided on Track circuited areas.

Most commonly used is GFN Liner

Different types of Liners used in Track

S.No Sleeper Rail Metal Liner

1 60Kg 60Kg T-3740

2 60Kg 52Kg T-3741/T-3742

3 52Kg 52Kg T-3738

Contd. …

S.No. Sleeper Rail GFN Liner

1 60Kg 60Kg T-3706

2 60Kg 52Kg T-3707/T3708

3 52Kg 52Kg T-3702

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