Transportation EngineeringAkhtar Abbas Assistant Professor

The University of Lahorewww.uol.edu.pk/ce

Department of Civil Engineering, (07-05-2013)

Railway EngineeringBrief History of RailwaysRailways originates in England, In 1784, mail coaches for carrying mails were introduced.In 1789 cast iron rails resting on stone blocks were introduced.The first ever railway in the world was opened for traffic on 27 September 1825*

Railway EngineeringThis railway line was run between Stockton and Darlington. The planning and design of railway line was carried out by George Stephenson.In France the first railway was opened in 1828 with horse as a tractive power. Passenger traffic had started in 1832, but steam locomotive were used in 1842.*

Railway EngineeringThe first railway line in America was laid in 1833.The first railway line in India was opened for traffic on 16th April 1853 between Bombay and Thana, a distance of 33 Km*

Railway EngineeringAdvantage of railwaysRailways have helped in the mass migration of the people in search of the better prospect of livelihoodRailways provide safe and convenient mode of transport to peopleRailways play a vital role in transporting goods from one region to other.*

Railway EngineeringRailway Track A railway track is a combination of rails, formation, ballast, sleepers and fasteningsIt also called permanent wayIt costs nearly 40% of the total investment to the railways.*

Railway EngineeringRequirement of Ideal TrackThe gauge of track should be correct and uniformThe alignment of track should be correct In straight reaches the rail level should be same, while on curves proper super elevation should be provided *

Railway Engineering4. The gradient should be uniform. Any change in gradient should be followed by vertical curve.The track should possess sufficient elasticity.The track should possess anti theft and sabotage quality.

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Railway EngineeringThe track should be constructed in such a way that its maintenance cost is minimum.The track should be design in such a way that the load of train should be distributed uniformly over it.The track should be high resistance to damage at the time of derailment.*

Railway EngineeringCapacity Of Railway TrackThe maximum number of trains that can be run safely on any given length of the track per hour. In actual practice it is some what less due to safety consideration. The maximum # of trains which can be handled in a yard per day is known as terminal capacity.*

Railway EngineeringFormationThe surface prepared to receive the ballast, sleepers and rails for construction the railway track is called formation or sub grade, depending upon the ground conditions, the formation may be in embankment or cutting*

Railway EngineeringFunction of FormationIt provides a smooth and uniform bed on which the track is laid.It bears the entire load transmitted from the moving loads to it through the ballastIt provides drainage facilities.It provides stability to the track.

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Railway EngineeringDesign AspectsWidth, The width of formation depend upon the following factorsNumber of track to be laid over itGauge of track.Width of ballast layer.Width of drains provided*

Railway EngineeringHeightThe height of the formation depends upon the topography of the alignment and the gradient adopted.Side SlopesThe side slopes of the formation depend upon the characteristics of the soil, as shear strength, angle of repose.*

Railway Engineering Angle of Reposeis the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is in the range 090.*

Railway Engineering*

Railway Engineering*

Railway EngineeringCONSTRUCTION OF RAILWAY TRACK IN DENMARK ON June 25'th 2010 BY USING Plasser & Theurer equipment (Attached movie)http://www.youtube.com/watch?v=Bk82bgPUcAM

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Rail GaugesThe minimum perpendicular distance between the inner face of the two rails.In some countries gauge is measured at a point 14 mm below the top of rails.It is difficult to spell out the reasons of adopting different gauges in different countries or in a country.

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Rail Gauges*

Rail Gauges*

Rail GaugesFactors Affecting the Choice of GaugeTraffic conditionsIf the intensity of traffic on track is more, a gauge wider than the standard gauge may be adopted. For such a condition a gauge width of 1676 mm (5-6) is more acceptable as the cost of operation per tone-km will be less for more carrying capacity, known as Broad gauge (B.G)*

Rail GaugesDevelopment of poor areasTo provide rail facilities for the development of poor areas, small gauge than standard may be adopted. It is known as narrow gauge. The width of this gauge varies from 762 to 610 mm.

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Rail GaugesCost of the trackIf the sufficient funds are not available for the construction of standard or Broad Gauge railway track, then meter gauge 1000 mm gauge is adopted for this area.Cost of constructionThere is not an appreciable increase in the cost of construction due to increase *

Rail Gaugesin the width of gauge due to following reasonsThe cost of bridge, tunnels, station, staff quarter buildings, signals and level crossing etc. is same for all gauges.Cost of earth work, sleepers, ballast etc. however will increase proportionally to the gauge width.*

Rail GaugesThe cost of acquisition of land for permanent land width increases proportionally with the increase in gauge width. Cost of rolling stock will be independent of gauge width.*

Rail GaugesSpeed of movement The speed of a train is proportional to the gauge . It is also a function of wheel diameter and the wheel diameter is kept 0.75 times the gauge width. Hence for higher speed Broad Gauge is prefered*

Rail GaugesTopography of area or the nature of countryIn hilly areas narrow gauges 762 to 610 mm gauge track is more useful as it is more flexible and can be laid of a smaller radius on the curve.*

Rail GaugesTypes of GaugesBroad GaugeStandard gaugeMeter GaugeNarrow Gauge*

Rail Gauges*

Rail Gauges*

Rail GaugesDisadvantages of Adoption of Different GaugesInconvenience to passengersAt the place of change of gauge, passengers have to move from one train to another train. This trans-shipment causes great hardship to passengers such as climbing stair cases of over head bridge,*

Rail Gaugesmovement of luggage, getting suitable accommodation in the new train.Transhipment of goodsLabor problemDamage of goods while trans-shipmentTheft or Misplacement of goodsTo store goods, costly yards are required at the junctions of two gauges*

Rail GaugesHindrance to fast movement of goods and passenger trafficInefficient use of railway stockAs meter gauge wagons and locomotives can not be used on broad gaugeDuplicity of equipment at stationsAt station where two gauges meet,*

Rail Gaugesduplicate facilities such as platform, clocks, ticket office, sanitary arrangements, etc. have to be provided, which will involve extra expenditure.Difficulty in war timeDifficulty in future*

Rail GaugesLoading GaugeLoading gauge consist of a vertical post with an arm. A steel arc is suspended from the top. It is constructed at the exit of the goods yard.FunctionIts main function is to confirm that the top of the loaded wagon would clear all the *

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Rail Gaugesstructures along the track such as tunnels and bridges etc. It represents the maximum height and width up to which a wagon should be loadedConstruction GaugeBy adding suitable clearance at the top side of loading gauge, construction gauge is obtained*

Rail GaugesFunction of construction gaugeIt decided the dimensions such as height and width of structure such as bridges and tunnels along the track, so that all wagons may pass through them without any damage to the structures.

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Rail Gauges*

Rail Gauges*

RailsRail is an iron beam. Its main function is to provide a most economical, smooth and level surface for the smooth passage of heavily loaded vehicles at great speed. The two rails of the track also serve as lateral guide for the running of the wheel.*

Rails*

Types of Rails Rails can be classified into the following categories:Double headed railBull headed railFlat footed railDouble Headed RailIt is of I section or dumb bell section. *

Types of RailsIt is the original rail. The idea was that when the head of the rail was worn out during the period of service, the rail could be inverted and reversed without incurring any extra expenditure. Such a rail have to be supported in chairs which rest on sleepers. Later it was found that during the service the bottom table of the rail*

Types of Railswas dented by the long and continuous contact with the chair to such an extent that it was impossible to reuse it. Hence it was rejected and other types of rail was searched.Bull Headed RailIt is similar in shape to double head rail. The only difference between double *

Types of Railsheaded and bull headed rail is that in bull headed rail more metal is added to the head to allow the greater wear and tear. The lower head or table was kept of just sufficient size to be able to withstand the stresses to be induced by moving loads. This rail also required chair for fixing it to the sleeper. This proved the greatest draw back of this rail*

Types of RailsFlat Footed RailIt is inverted T shaped rail. It was developed by Charles Vignoles as earlier as 1836. It posses the following advantages over double headed and bull headed railFor fixing this type of chair to sleepers, no chairs are required. The foot of the *

Types of Railsrail may be spiked direct to the sleepers. This effects economy to a great extent.For the same weight, this type of rail is stronger both vertically and laterally than the bull headed rails.This type of rail is cheaper than bull headed railsThis type of rail requires less fastenings

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Types of Railsthan B.H. railsV.F.F. rails distribute train load over a larger number of sleepers, which gives a better stability to the track.F.F. rails gives longer life to the track and reduce maintenance cost.Some engineers feels that B.H. rails gives better alignment, more solid and smooth track*

Types of Rails*

RailsRequirement of an Ideal Rail It should be possess adequate lateral and vertical stiffness.The shapes of the bottom of the head and top of the foot should be such that fish plate could be fixed easily.The C.G. of the rail section should be located very near the centre of the height

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Railsof the rail.4. To allow the sufficient margin for the vertical wear, the depth of the head of rail should be sufficient.5. The rail should be shaped suitably.6. The metal distribution in head, web and foot of the rail should be proper and balanced.*

Rails7. The surfaces and gauge faces of the rail should be hard and capable of resisting wear.8. The thickness of the web of the rail should be sufficient to withstand the load likely to come on the rail.9. The width of the foot of rail should be sufficient to spread the load on large area of sleepers*

Rails10. The contact area between the rail and the wheel should be sufficient to minimize the contact pressure.*

Defects in RailsDue to the passage of moving of a number of wheels and the friction between the wheel and the rail, the rail head gets worn out in course of time. The impact of moving loads, the forces due to rail wheel interaction , braking of wheels and effect of weather conditions caused considerable wear and tear on*

Wearing of Railsvertical and lateral planes of a rail head.Wear of rail head can be classifiedWearing on top or head of a railWear at the end of a rail Wear on the sides of a rail*

Wearing of RailsWearing on top of railThe metal from the top of the rail flows and assumes the shape forming projections on the sides. These projections beyond the original section of the rail are known as burrs.Causes of Wear on top of a railThe head of rail worn out due to the *

Wearing of RailsAbrasion of the rolling wheels over the rail.2. Due to the concentration of heavy wheel loads on a very small area, high stresses in rail exceeding the elastic limit are produced. Due to these high stresses the metal from the top flows out. This factor is more significant than the first in producing wear in rails. *

Wearing of RailsThe grinding action of the sand particles between the wheel and rail also help to produce wear of a rail.Corrosion of rail, also help in wear of top of a rail.II. Wear at the end of a railAt the joints due to the hammering action of the moving wheel cause the wear of *

Wearing of Railsthe rail at its ends. It is more pronounced than the wear on the top. This wear is also known as rail end batter. The rail end batter is measured as the difference between the vertical height of rail at the end and at a distance of 30 cm from the end. If the batter is up to 2 mm, it can be tolerated and it is called as average batter. *

Wearing of Railsbut a batter 2 and 3 mm is known as severe and in this condition rail end needs correction. If the batter is excessive and rail is otherwise alright , a portion of the rail may be cut off and it can be reusedEffect of End Wear of a RailDue to the impact blows of the moving wheels on the end of the rail, Results*

Wearing of RailsThe contact surfaces between rails and sleepers get worn out.Fish bolts and fish plates becomes loose.Due to vibrations at the joints, the settlement of the ballast takes place, which results in depression of the sleepers. The defect is enlarged due to the following factors.*

Wearing of RailsDue to heavy loads and large joint openingDue to bad conditions of vehicle springs.Due to poor maintenance of the track.IIIWear on the sides of a RailThis is the most destructive type of wear and occurs when the tracks are laid on curves.*

Wearing of RailsThese type of wear is caused by the following factors.On curved portion of the track , the centrifugal force causes thrust of the wheel flanges against the side of the outer rail head, which results in the grinding of the rail by the flanges producing side wear on the outer rail.

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Wearing of Rails2. On curved portion of the track, the vehicles do not bend to the shape of the curvature, resulting into biting of the inner side of the outer rail head by wheel flanges i.e., due to rigidity of wheel base.3. Wear on inner side of head of the inner rail also occurs. It takes place mainly due to slipping and skidding action of wheels on curves.*

Measure to minimize Wear to RailsBy coning the wheelsBy providing the super elevation on the track.By the use of special alloy steel for rails.By adopting good maintenance of track.By reducing the expansion gap and number of joints.

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Measure to minimize Wear to Railsvi. When the wear exceeds 5% of the total weight of the section. The rail must be replaced.vii. Regular tightening of fish bolts and packing of ballast will reduce wear*

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RAILWAY TRACK ENGINEERINGGOOD LUCK FOR MID TERM"How can one be considered among the people of knowledge when his worldly life is dearer to him than his Hereafter?" Prophet Isa (as)

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