transportation engg 2 cv63

8/12/2019 Transportation Engg 2 CV63

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Railway Engineering

Introduction

The two important modes of land transportation are Railways, Highways.Railways constitute the largest single commercial and public utility undertaking in

India.The first public railway in the world was opened to traffic on 27 thSeptember !2"

between Stockton and #arlington in $%The first railway line in India was opened for passenger traffic in !"& between

Thane and %alyan in 'umbai, in India, for a distance of 2 miles (&2 kms).

The Indian railway system has been di*ided into +onal railways.

Slno

Railway one -ode Headuarters

-entral -.R 'umbai

2 /astern /.R %olkata

& 0estern 0.R 'umbai1 orthern .R #elhi

" Southern S.R -hennai

3 orth4 /astern ./.R 5orakhpur

7 orth /ast 6rontier ./.6.R 5uwahati

! South -entral S.-.R Secunderabad

South /astern S./.R %olkata

8 South 0estern S.0.R 9angalore

These +onal railways take care of railway business in the respecti*e areas and are

responsible for all management and planning of works.:part from +onal railways, there are 1 manufacturing units.

Sl no 'anufacturing $nits Headuarters 6unctions

-hittaran;an

locomoti*e works

-hittaran;an 'anufacture of

electriclocomoti*e.

2 #iesel atiala 'anufacture

#iesel-omponents

Track Specifications on Indian Railways

) 6or Single lines , formation is3.8 mts wide for 95, 1.! mts wide for '5

2) 'a?imum #egree of -ur*ature permissible on a 95 8 8and '5 is 3 8&) 9allast used mostly is broken stone 28 cm to 2" cm cushion of ballast is

normally gi*en below the bottom of sleepers.

Transportation Engineering II CV63 1


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1) Sleeper density is the number of sleepers per rail length it *aries from '@3to '@& for main tracks and where ' is the length of rail in mts.

Track Rail Section(kg/m)

Rail Length Sleepers Perkm (number)

allast!ushion

(cms)

95 11.31 to "2 &

mts( 2.!mts)

&8 to "18 " to &8

'5 2.73 to &7.2 2mts &8 to "18 " to 2"

5auges in Railway Track

The gauges of a railway track is defined as the clear distance between the inner orrunning faces of the two rails which form the track.

In India , the e?isting gauges areA

) Standard 5auge or 9road 5auge 95 B 373 mm ( " C 3D)2) 'eter 5auge '5 B 888mm ( &E & &F!D)

&) arrow 5auge 5 B 732 mm ( 2E 3D)oteA The wheel diameter is generally 8.7" times that of 5auge.

6actors go*erning the selection of a suitable gauge

) -ost of construction A There is little increase in initial cost.

2) =olume of and nature of trafficA /? for hea*ier loads and high speeds, widergauges are reuired.

&) >hysical features of countryA e?A 5 is suitable in hilly countries1) Speed of mo*ementA for maintaining high speeds, 95 is prepared.

-lassification of railway linesA

#epending upon the importance of routes traffic carried and ma?imum permissible

speed Indian railways line ha*e been classified into & main categories.) Trunk routes

2) 'ain lines&) 9ranch


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-omparison between railways and roadwaysA

Slno

Roadways Railways


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9o?ing

The process of filling the ballast around the sleepers is called bo?ing of the ballast.

9road gauge (Standard gauge)The gauge of the track in which the distance between the runnings faces of two

tracks rails is .373mts.

9uckling of rails

The railway track gets out of the original position if the e?pansion of rails is

pre*ented during hot weather this is known as buckling of rails.

-ant or super ele*ationAGn cur*es to counteract the effect of centrifugal force the le*el of the outer rails is

raised abo*e the inner rail by a certain amount, this raising of outer rail o*er innerrail is called superele*ation or cant.

-apacity of track

-apacity of track is the number of rains that can run safely on a track per hour.

-hairsA - .I chairs are used to hold the bull headed and double headed rails, thesechairs are fi?ed to sleepers by round spikes.

-utting0hen the ground has to be cut or e?ca*ated for pro*iding the railway line at reuired

le*el below the ground le*el is called cutting

/mbankment

The raised bank of earth constructed abo*e the natural ground le*el for carrying therailway track is called embankment.

6ormation6ormation is the prepared Subgrade ready to recei*e the ballast.

5auge

The clear distance between the inner or running faces of rails near their tops isknown as the gauge of the track.

5oods yard: yard in which the goods wagons are shunted and sorted for loading and unloading

is called a goods yard.

5radient:ny departure of the railway track from the le*el is known as grade or gradient, it is

called an upgradient when the track rises in the direction of motion, and downgradient when track falls below in the direction of mo*ement.

Hauling capacity

Hauling capacity of locomoti*e is the total load which can be hauled by it indicatesthe power of the locomoti*e.

unction stationA

0hen two or more railway line meet at a station it is called a ;unction station, the



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line s may be of same gauge or different gauges.

%eysAIt is tapered pieces of timber or steel to fi? the rails to the chairs on metal sleepers.


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To reduce the risk of derailment and achie*e more safe and comfortable operationthe circular cur*es must be ;oined by transition cur*es, the cur*ature and super

ele*ation should be attained gradually. Transition cur*es is defines as a cur*e ofparabolic nature which is introduced between a straight and a circular cur*e

'arshalling yardsA yards in which wagons are sorted and new trains are formed are

called as marshalling yards.'etal sleepersA sleepers made of cast iron or steel are called as metal sleepers. -ST

sleepers, (-entral Standard TrialA -ST) are most commonly used on Indian

railways.

'eter gaugeA The gauge of a track in which the distance between the running facesof two tracks rails is one meter.

arrow gaugeA the gauge of a track in which the distance between the running faces

of two tracks rails is either 8.732 mts or 8.3 mts

>latformA a raised le*el surface from where passengers board and alight a from

trains at station is called a platform.

Rolling StockA Rolling stock consists of locomoti*es, passenger coaches and goods,

wagons, the term is used because they roll on rails.

Shunting operationA the mo*ement of rains and locomoti*es in the station yard forthe purpose of sorting, recei*ing, attaching, or detaching to make new trains ready

for dispatch are called as shunting operations.SidingA when a branch starting from a main line terminates at dead end with a buffer

stop or sand hump, it is known as siding.

TractionA The source through which the locomoti*e deri*es power is called traction, it

may be steam traction, diesel traction, or electric traction etc.,.

Permanent %ay or Railway Track$



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>ermanent way or railway track is the rail road on which the trains run , it consists oftwo parallel rails, sleepers, fittings , fastenings, ballast, formation etc., In a

permanent way , the rails are ;oined to each other by fish plates and bots and arefi?ed to sleepers by different yes of fastenings , the sleepers are properly spaced and

embedded in ballast, the ballast rests on the prepared Subgrade called theformation.The rails act as girders to transmit the wheel load to the sleepers, the sleepers hold

the rails in proper position with respect to the proper tilt gauge and le*el and

transmit the load from rails to the ballast. The ballast distributes the load o*er theformation and holds the sleepers in position it also pro*ides drainage.

oteA Gn cur*ed tracks, super ele*ation is maintained by ballast and the formation isle*eled minimum ballast cushion is maintained at the inner le*el, while the outer rails

get more ballast cushion.

Reuirements of Ideal permanent wayA

: good permanent way or track should gi*e comfortable and safe ride at ma?imum

permissible speed with minimum maintenance cost to achie*e this, the basicreuirement areA

) The gauge should be correct and uniform.2) The two rails should remain at the same le*el in as straight track, on cur*es

the outer rails should ha*e proper super ele*ation.&) The alignment should be straight and free from kinks.

1) The gradient should be uniform and any changes of gradients should befollowed by a smooth *ertical cur*e.

") The track should be resilient and elastic to absorb shocks and *ibrations.3) The track should ha*e good lateral strength so as to maintain its alignment

and its stability.

7) The track should ha*e good drainage to a*oid water logging.!) There should be pro*ision for easy replacement and renewals of *arious

track components.) The track should ha*e such structure that its initial cost is low and

maintenance is minimum.



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"2 kg railA "2 kg F meter.The weight of a rail and its section is decided on the following factors,

) Hea*iest a?le load.2) 'a?imum permissible speed

&) #epth of ballast cushion1) Type and spacing of sleepers.

-omparison of rails typesA

Sl'no

Particulars lat #ooted rails ull headed anddouble headed rails'

Strength and Stiffness 'ore


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-reep A The creep is the longitudinal mo*ement of rails in a track , this results in

buckling which may be lead to derailment of trains and hence serious loss of life orproperty.

-auses of creepA

These are based on the wa*e theory, dragging theory and percussion theory in

general they are due toA

) 5rowing out effect of the mo*ing wheel on the wa*e formed in the rail.

2) Impact of the wheels at the rail end at ;oints&) Tendency of the wheels to push the rail forward and backward during

braking and acceleration , deceleration, and running1) $nbalanced traffic

") /?pansion and contraction of rails. #ue to temperature *ariations.

/ffects of creepA

) Sleepers mo*e out of position, this affects gauge and alignment of track.2) The ;oints get ;ammed , this results in the formation of kinks

&) Rail ;oints get opened out, this results in elongated bolt holes and fracturingof fish plate and bolts.

1) >oints and crossings get distorted operation of switches and interlockingsystems are made difficult.

>re*ention of creepA

) 9y pulling back the rails

2) 9y pro*iding anchors or anti creep bearing plates

&) 9y using steel sleepers.1) 9y increasing the number of sleepers.

:nchorsA

:nchors are anti creep de*ices, they are fitted to the foot of the rail in contact withthe side of sleepers their function is to pre*ent creep.

0ear of RailsA

0ear is one of the ma;or defects of rail which de*elop during the ser*ice life. #ue tomo*ement of hea*y loads at the speeds and friction between the rail and the wheel

the rail head gets worn out in course of time, as such lot of metal gets worn out ofthe rail head and there is sufficient loss of weight of the rails. The amount of wear

should not be more than "K of the weight of rail.

Rail ointsARail ;oints are necessary to hold together the ad;oining ends of the rails in the correct

position both in hori+ontal and *ertical planes.Rail ;oint is the weakest part of the rail, there are two types of rail ;oints.

) Supported oint2) Suspended oint



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Supported ointA In this ;oint the rail ends are supported on a single sleeper , this;oint is not recommended

Suspended ointsA in this ;oint the rail ends are pro;ected beyond the sleepers calledas shoulder sleepers.

Suspended ;oints are most commonly used with timber and steel trough sleepers inIndian railways.

0elding of railsA

The main purpose of welding of rails isA) To build up the worn out parts of point and crossings

2) To build up the worn out heads of rail ends&) To increase the rail length thereby reducing number of ;oints

oteA the Indian practice is to weld ma?imum of " rail lengths.

:d*antages of welding of railsA) 9y forming a strong ;oint, it increases the life of rails and reduces

maintenance cost.

2) It reduces creep as the length of rail increases.&) /?pansion effect due to temperature is reduced which also reduces creep.

1) #efects such as hammering on rail ;oints, displacement o ;oint, disturbance inalignment and running surface are eliminated.



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SleepersSleepers are members laid trans*erse to rails on which the rails are supported and

fi?ed.6unction of sleepers.

) To held the rails to correct gauge and alignment.2) To gi*e a firm and e*en support to rails

&) To transfer the load from rails to the ballast.1) To act as an elastic medium in between the ballast and rails.

") To pro*ide general stability to the permanent way.

Reuirements of an ideal way.

) Initial cost and maintenance coats should b minimum.2) It should ha*e moderate weight.

&) The design of sleeper and fastenings should be such that it is possible to fi?and remo*e the rails easily.

1) The sleeper should be such that it is possible to maintain and ad;ust guge ,

track alignment and le*els of the rails.") The sleeper should ha*e sufficient bearing area.

3) The sleepers should ha*e capable of resisting shocks and *ibrators due tohea*y loads of high speed trains.

Types of sleepersA) 0ooden sleepers A timber sleepers

2) 'etal sleepers Aa) -ast iron sleepers

b) Steel Sleepers.&) -oncrete Sleepers

a. Reinforced -oncrete Sleepersb. >restressed -oncrete Sleepers

0ooden Sleepers

0ooden sleepers or timber sleepers is the most ideal sleeper, the life of the wooden

sleepers depends upon their ability to resist.) 0ear2) #ecay

&) :ttack of termites ( white ants)1) Luality of timber used.

Si+e of sleepersA

auge Si*e in mts Si*e in #eetand inches

9road 5auge 2.7"M8.2"M8.& E M 8D M "D

'eter 5auge .!8M8.28M8."

3E M !D M 1D

arrow 5auge ."8M8.!M8.

"

"E M 7D M 1D



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:d*antages of 0ooden SleepersA) -heap and easily a*ailable

2) 6ittings for wooden sleepers are few and simple&) Resists shocks and *ibration due to hea*y mo*ement of *ehicles

1) /asy to lay, relay, pack, lift N maintain.") Suitable for all types of ballast

3) :lignment can be easily corrected.7) 9est suited for track circuited sections.

#isad*antagesA

)


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9:


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3) %ankarA this is a soft material and rails to powder under loads , it is used for'5 and 5 tracks with light traffic and where a better type of ballast is not

a*ailable.7) 9rick ballastA where no stone or substitute a*ailable, o*er burnt bricks,

broken into small si+es and used as ballast, it powders easily and rails mayget corrugated.

!) 9last furnace slagA this is suitable as ballast material if it is hard dense andfree from gas holes.

Renewal of 9allastA

) 9allast should be periodically due to continuous mo*ement of the trains on

the track the ballast gets crushed and reduces its si+e.2) #rainage is obstructed due to the crushed particles which accumulates in the

*oids.&) #epth of ballast reduces due to hea*y load on it.



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R:I< 6IMT$R/S :# 6:ST/I5S>urpose and typesA

Rail fi?tures and fastenings are used to keep the rails in proper position they link therails endwise and fi? the rails to sleepers.

The important fittings used in a permanent way areA) 6ish plates

2) Spikes&) 9olts1) -hairs

") 9locks

3) %eys7) 9earing plates.

) 6ish platesA

6ish plates are used to hold the two rails together both in th hori+ontal and *ertical

planes they also pro*ide for any e?pansion or contraction of the rail caused bytemperature *ariations.

2) Spikes A spikes are used for fi?ing rail to the wooden sleepers, the *arious

types of spikes area) #og spikes

b) Screw spikesc) Round Spikes

&) 9oltsA bolts called as dog or hook bolts are used to fi? sleepers resting directly

on a girder.

1) -hairs A chairs are used for holding double headed and bull headed rails") 9locksA small blocks are inserted in between two rails to pro*ide the desired

gap as in aces of check and guide rails in crossings.3) %eys A kesy are small tapered pieces of steel to fi? rails to chairs on metal

sleepers.7) 9earing plates A bearing plates are rectangle plates of 'S and -I they are

used for fi?ing wooden sleepers to 66 rails to distribute the load on a largerare of sleepers.

:d*antages of bearing platesA

) To distribute the load coming on rails to the sleepers o*er a larger area andthus pre*ent sinking of the rails in the wooden sleepers.



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2) To pre*ent the destruction of the sleeper due to rubbing action of the rail andthus increasing the life of the sleeper.

&) o ad+ing of sleeper is reuired when bearing plates are used because thebearing surfaces are canted at in 28, this gi*es uniform distribution of load

o*er sleepers.1) They help in firm holding of spikes to the sleepers and thus pre*ent the

shifting of rails.") 9etter maintenance of gauge is possible.

#isad*antages of bearing plates.

) The plate shakes when loose2) 0hen a new hole is to be made for any in;ured hole all the spikes in the

bearing plate ha*e to be pulled out.&) 0hen bearing plates are loose , they admit moisture and increase mechanical

wear of the sleepers.



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Stations and yardsRailway stationA it is selected place in a railway line where trains e?change of

passengers and goods, it is also use for watering and cooling, ser*icing of engines,sorting of wagons, and control of mo*ements

unction stationA0hen two or more railway lines meet at a station, it is called a ;unction station, the

lines may be of same gauge or of different gauges.Terminal stationAStation at which the continuation of a main line is stopped is called a terminal

station.

0ay side stationA:ll stations other than terminal and ;unctions are called way side station.

These stations consist of an arrangement for crossing an up and down train or foro*ertaking the slower trains by the fast mo*ing trains.

: way side station layout may be pro*ided in the following ways.

) : way side station on a single line.

This is the simplest layout of a way side staion which consists of

a) : through lineb) : loop line to enable trains to cross each other

c) : passenger platform and a station building

d) : goods loop and a goods platform.latformA



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: raised le*el surface from where passenger board and alight from trains or loaingand unloading of goods is done is known as platform,

Types of platformA) >assenger platform

2) 5oods platform

>urpose of platformA) 6or e?change of passengersFgoods.2) 6or controlling trains mo*ement

&) To enable to o*ertake

1) 6or taking diesel F coalFwater for locomoti*es") 6or e?changing engines F staff

3) 6or attaching or detaching wagons7) To pro*ide shed for locomoti*es F wagons

5radients in yard in 188.

-onsiderations for selection of site of a railway station.

) :deuate landA adeuate land should be a*ailable not only for station building

and the proposed line but also for future e?pansion.2)


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TriangleA this consists of three sides of short length tracks in he form of a triangle,such triangles are pro*ided for changing the direction of engines.

Turn tableA a turn table is an arrangement for turning the engine by supporting ito*er a centrally pi*oted girder.

0ater columnA water columns are pro*ided fr feeding water to steam locomoti*es.: water column consists of a *ertical pipe with swi*eling hori+ontal are fi?ed near

the track for supplying water to the locomoti*es and bogies from an o*erhead tank.9uffer stopA buffer stop is a type of barrier placed at the dead end of a siding topre*ent *ehicles from running off the track.

Sand humpA this is a method to pre*ent the *ehicles from running off the track at h

end of a siding, a hump of sand with a rising gradient a he dead end of a siding ispro*ided.

6ouling markA a fouling mark is pro*ided between two con*erging tracks at a pointbeyond which the centre to centre distance of track is less than the minimum. It

indicates a foul or possibility of collision of *ehicles beyond these points.



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P+I,TS -," !R+SSI,S

>oints and crossings are the arrangements by which railway *ehicles can pass fromone track to another.

They are also useful for marshalling and shunting work in station and yards.The ob;ects of points are to di*ert the train and the ob;ect of crossing is to pro*ide

gaps in the rails through which the wheel flanges can pass. They control themo*ement automatically in the desired direction and the dri*er is not reuired to doanything.

TurnoutA a turnout is a combination of points and crossings which enables the traffic

to be di*erted to the left or right of the traffic. /?A from main line to branch line orsiding.

Reuirement of an Ideal crossingA) It should be rigid to withstand *ibrations.

2) The wing rails should be special steel to resists hea*y wear due to themo*ement of wheel.

&) It should ha*e sufficient thickness to take all stresses occurring at crossings.



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Signalling and interlockingThe purpose of signalling and interlocking is to control and regulate the mo*ement of

trains safely and efficiently.Signalling includes the use and working of signals, points, block instruments and

other euipments.Interlocking is an arrangement of points and other appliances which ensure proper

and safe working of the signals. The setting of points and signals is so arranged thatonly the desired mo*ement for the train is open and all the others are locked.Interlocking eliminates human error and pre*ents accidents and derailments.

Gb;ects of signallingA

) To regulate mo*ement of trains to run safely at ma?imum permissible speed2) To maintain safe distance between trains running on the same line in the

same direction.&) To ensure safety between two or more trains which cross or approach each

other.1) To pro*ide facilities for safe and efficient shunting operations.

") To regulate arri*al and departure of trains from station yards.3) To guide the trains to run at restricted speed during maintenance and repairs

of the track.

Types of signals) Hand signalsA are gi*en either by flags red or green fi?ed to a wooden handle

or by bare arms when flags are not *isible during day time, in night handlamps with mo*eable green and red slides are used. The hand signals are

generally used by guards, station masters, cabin men, bang men etc.,2) #etonating signalsA during foggy and cloudy weather, detonators are laced on

the rails which e?plode with a loud sound when the train passes o*er them.The sound alerts the dri*er to look for the approach of signals.

&) Semaphore signalsA this is so designed that if there is any failure in workingof the euipment, the signal will always show C Stop >ositionE, the semaphore

signal can be used as Cstop signalE as well as C 0arner signalE.

1) 0arner signalA this signal is meant to warn the dri*er that the train isapproaching the stop signal and so to control the speed. The 0arner signal is

placed on the same post of the semaphore signal below it. The 0arner signalis similar to semaphore signal in shape e?cept for a * notch at free end. The

white strip is also * shaped.") -olor light signalsA these signals consist of colored light both during day and

night. These are used in suburban sections and on sections with high traffic

density.

Track geometricsA

Reuirement of mode of communication) Speed

2) Safely&) -omforts.

It includesA) -Fs sPof elements O gauges , ballast, side slope, permanent land

2) 5radient4 ruling, ma? and min&) -ur*es

1) Super ele*ation or cant, its deficiency , widening etc.,



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&aintenance o# TrackIt is essential to maintain the track in god condition so that trains may run safely at

permissible speeds.ecessity for maintenanceA

) #ue to constant mo*ement of hea*y and fast trains, he packing under hesleepers gets loose, the gauge, alignment, and le*els get disturbed, this

endangers the safety of track.2) #ue to *ibrations and impact of fast mo*ing trains, fittings of track get loose.&) The track and its components are sub;ected to wear and tear due to effects of

rain, sun and wind.

'aintenance of trackAIn India , maintenance is carried out by manual labour, the maintenance of rack is

di*ided into 2 partsa) #aily maintenance

b) >eriodic maintenance.

a) #aily maintenance A this is carried out by full time maintenance gangs

throughout the year, the railway track is di*ided into suitable sections and one

gang is attached to each section for maintaining that section in goodcondition.

b) >eriodic maintenanceA this is carried out e*ery 2 or &years , during periodic

maintenance the gauge le*els, alignment, points , and crossings etc., arethoroughly checked to bring the track to perfect condition by remo*ing all its

ma;or and minor defects.Track maintenance work should include the following itemsA

) Surface of rails2) Track alignment.

&) 5auge1) >roper drainage

") Track components ( formation, side slopes, ballast, and fi?tures)

3) 9ridge and its approaches7) Rolling stock

!) >oints and crossings)


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'aintenance euipments and tools reuired in maintenance works) 'easuring euipments

Sl

no

ame of euipment 6unction

Rail guage To check the gauge of

the track

2 Straight edge or spirit le*el To check the gauge

as well as cross le*el

& -ant 9oard To check the

difference in cross

le*els or superele*ation

1 'allet or wooden hammer To check ad+ing of

sleepers

" T suare To check the suare

ness of sleeper3 Stepped feeler To measure the wear

or the clearances

2) 'aintenance Tools

Slno

ame of /uipment 6unction

Sleeper tong To carry the sleepers

2 Rail tong To lift and carry the rails

& 9eater or pick a?e To pack the ballast under the sleepers

1 -row bar To correct the track alignment and to lift the

track for surfacing, also to take out dog spikes

" im crow To bend the rails or to cut the rails

3 a) Spiking hammerb) %eying hammer

a) To dri*e the dog spikes, cotter etc.,b) To dri*e keys

7 Spanner To tighten bolts

! 0ire claw or ballast rake To draw or take out the ballast while

doing screening , packing etc.,

>haraoh To dig the earth or to take away ballast

8 :uger To drill holes in wooden sleepers.

9o? spanner 6or dri*ing

2 0ire basket 6or screening the ballast

& >an mortar iron 6or leading earth etc.,

#uties of a permanent way inspector (>0I)

) The duties of >0I are that he is responsible for maintaining the track in goodcondition. It is his duty to get defecti*e track repaired by his gang of workers.

2) He inspects the track of his section in a push trolley or a brake *an 2 to &times in a week, he notes down the defects such as bad alignment , kinks

irregular e?pansion, gaps , sags , defects in points and crossings etc., andrectifies them to keep the track in best condition for passage of trains.



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.-R+R E,I,EERI,

0' %ith a neat sketch show the 1arious components o# a harbour and

e2plain the #unction o# each'

T3PI!-L L-3+T + -, -RTII!I-L .-R+R

Harbour can be defined as a sheltered area of the sea in which *essels could belaunched, built or taken for repair, or could seek refuge in time of storm, or pro*ide

facilities for loading and unloading of cargo and passengers.

. /TR:-/ -H:/I/R :# /TTJAThese are docks, which pro;ect into water. They may be of solid

or open type. : ;etty is pro*ided near the entrance channel for reducing the silting of the

channel. : pier is referred to as a mole and in combination with a breakwater, a

breakwater pier.&. T$RI5 9:SIAThis is the water area reuired for maneu*ering the ship when it

goes to or lea*es the berth, so that the ship can proceed head on.1. #RJ #G-%AThey are primarily pro*ided for maintenance, repairs and construction

of ships.



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4' .ow are harbours classi#ied5 +n what basis the si*e o# the harbour isdecided'

Harbours can be broadly classified as

) :T$R:< ) H:R9G$R G6 R/6$5/

2) S/'I4:T$R:< 2) 'I


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(!) #efence and strategic aspects.() :*ailability of electrical energy and fresh water.

,E!ESSIT3 +R "+!9S

: dock is a general term used to describe the marine structure, which is used for themooring or tying of the *essels, for loading and unloading cargo or for embarkingand disembarking passengers. In many countries, there are large *ariations in tidal

le*el. Hence, open berthing becomes impossible. In such cases, an artificial basin

pro*ided with gates4called the wet dock is created for the smooth transactions withthe *essels In basins, where the water is pumped out, to carry out repairs to the hull

of a ship, then such a basin is called a dry dock. There are also other types of repairfacilities such as floating docks and slipways. The different types of docks and repair

facilities will be discussed in this chapter.

The general form of accommodation in any port can be in two formsA

() Gpen berthing, sub;ected to the tidal fluctuations.

(2) /nclosed basins or wet docks in which the water is maintained at uniform le*el bymeans of gates.

The important consideration in pro*iding a particular type of berth depends upon themagnitude of tidal range present in the harbour. >orts with small tidal ranges are

pro*ided with open berths and those with large tidal ranges euipped with docks.

Gpen tidal berths ha*e great ad*antages from military point of *iew and also due toits low initial construction cost. Howe*er, the two ma;or disad*antages of this type

areA

() The necessity of keeping a watch on board the ship at all times for the purpose of

slackening out or taking in the shipQs mooring lines as the tide rises or falls.(2) The constant rearrangement of the inclination of the gangways, con*eyors, etc

which are used for handling the cargo between the ship and uay.

Hence in locations where the magnitude of tidal ranges is large, then the pro*ision ofdocks becomes necessary.

%ET "+!9S

The water le*els in this dock are maintained by a system of locks and lock gates. :pumping plant may also be necessary. 0et docks are highly useful in the following

situationsA

() 0here the tidal range is greater than " m.(2) In locations, due to e?cessi*e costs, the approach channel cannot be dredged or

maintained from deep draft *essels at low stages of the tide.(&) In harbour sub;ect to hea*y silting, the lock gates of a wet dock are *ery

effecti*e in pre*enting the silt in entering the basin area.



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The shape and the area of land a*ailable go*ern the form in plan of the wet docks.The three main types areA

() Rectangular basins with long straight uay.(2) Rectangular main basins with se*eral branch docks, and

(&) 9asins of irregular form following the course of ri*ers.

The different types are shown in fig below

!+,SI"ER-TI+,S I, "ESI,

-onsiderations of purely local nature ha*e an important influence in selecting the

particular design suitable for a wet dock. /*en though it is not possible to lay downany hard and fast rule, the following points deser*e considerationsA

() The most con*enient position.(2) The most suitable shape for a dock.

(&) The best ratio between periphery and surface and that between uay space andwater area.


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determining the unbalanced the lateral loads. The acti*e and passi*e earth pressurethat are pre*ailing must be gi*en due consideration.

REP-IR -!ILITIES

The essential facilities of a repair facility areA

() :ccessibilityA :ll the parts of the ships keel and underside must readily beaccessible.(2) =entilationA If a ship has to be painted, then it is essential that the sides of ship

should dry as uickly as possible. This is best achie*ed in open slip way and floating

docks.(&)


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The blocks on which the ship is allowed to rest when the dock is dry are of two types

4 the keel blocks and the bilge blocks. The keel blocks come directly under the hullline and the sides of the hull rests on the bilge blocks. These blocks are made of

indi*idual slabs of wood and are pro*ided with wedges to facilitate the ad;ustment ofthe heights of the blocks to enable the ship to be seated properly. The height of the

keel block should be such as to allow a person to pass through easily below the hullof a ship. :dditional support to the ship is gi*en by means of shores which the topportions of the sides of the ship to pro;ections on the walls.

T3PES + "R3 "+!9S

:ccording to the design, there are three types. These areA() 6ully hydrostatic

(2) >artially relie*ed and(&) 6ully relie*ed.

In the fully hydrostatic type, there is sufficient weight in the cross section of the dock

to resist the hydrostatic pressure when empty. It has the highest initial cost. The

maintenance cost of this type is less, because of limited pumping of seepage water.This type is located in case of porous water bearing soils.

In partially relie*ed type, there is reduced pressure either on floor only or on boththe floor and sidewalls. >artial relief is obtained through cutoff walls e?tending

beneath the entire dock periphery. The relief holes at the bottom floor admit waterfrom the sub soil. These types of docks are suitable in places where relati*ely

imper*ious soil e?ists either below the floor throughout the dock height as well.

The fully relie*ed type is constructed when a rock e?ists beneath the dock andthroughout its height. This type has only a thin concrete lining o*er the sides and

floor of the e?ca*ated basin. Relief holes are usually pro*ided for safety against

accidental pressure accumulation. The *arious types are shown in figA

L+-TI, "+!9S

The floating dry dock is a floating structure with a floor and two sidewalls wider than

the ship. It is used to lift the *essel out of water for the purpose of repairs and

ser*icing. It is usually power operated. It has a trough shaped cross section with apontoon floor supporting upright wing walls. It is sub di*ided into compartments,

which can be flooded by submergence dewatered by rising. Separate space ispro*ided in the upper portions of the wing wall for housing the motor and control

rooms for pumping and for storage of reuired materials.

The floating dry docks possess the ad*antage mobility, rapid construction and lowercost of pumping as compared to gra*ing dock. They may be mo*ed from one location

to another and towed from place to place. It is not necessary that they should beconstructed at the place where they ha*e to be used, but may be built where natural

and labour conditions are fa*ourable.



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T3PES + L+-TI, "+!9S

They can also be called as multi4section and single section respecti*ely. The singlesection dock is primarily used for military purposes for which there is adaptability to

sea going is a decided ad*antage. 6or commercial purposes, the multi4section dock isused most e?clusi*ely.

The singly4section dock may be opened at both ends or it may ha*e a closed bow ofthe shape of a ship with a hinged gate at the stern. 'ulti4section docks are of se*eral

types as gi*en below and are built to lift ships of all si+esA 4

(i) 'ulti4sectional dock.

(ii) /nd sectional dock. (iii) #etachable pontoon dock.

(i*) Gff4shore dock.

These types are shown in fig. 8.1.

The multiple section docks ha*e loosely connected for maintaining appro?imate

alignment without longitudinal rigidity. /ach unit acts independently in lifting a ship.

The number of sections used may be ad;usted to suit the length of the ships andadditional sections ca be added, if necessary. The length of each unit is less than the

distance between the wing walls so that each section may be docked upon one ormore of the remaining sections for carrying out maintenance ad repair.

The end sectional type of floating docks has a continuous central section and two

detachable end sections. The central section is lifted by the stepped arrangements of

the end sections for the purpose of repair. The central section is about two4thirds ofthe total dock length. This type of dock possesses longitudinal strength at the centre

as compared to that of a single4section dock.

The detachable pontoon type has a continuous trough supported on a number ofpontoons. The trough is made of steel. The pontoons are made of steel or timber and

can be docked indi*idually for repairs, etc.

The off4shore dock has one wall and a floor as shown in fig. 8.&.It is hinged to theuay wall and can operate only in that location.



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Tunnel Engineering

Introduction

Tunnel is an indispensable engineering structure to transport liuids or traffic belowground and sometimes below water. It is a *ery costly proposal, which reuiresthorough study of geological features of the site to o*ercome unforeseen problems.

>erfection in centerline transfer and grade into the tunnel determines the accuracyand dependability of tunnel. Suitable shape and si+e should be selected for the

tunnel depending on uantity on uantity of material to be transported and type ofmaterial. #epending on feasibility sometimes open cuts are preferred than tunnels.

Tunnels reuire more time and money for construction in addition to sophisticatedeuipment and technology. :lso tunnels are not free from routine maintenance

operation.

;ESTI+,S

. 0hat is a tunnel 0hat is its usefulness

:ns. Tunnel is an engineering structure that could be used as a passage orroadway below the ground or below the bed of a stream or ri*er or sea or

through a hill or mountainTunnels may be used for the transport of passengers in *ehicles, trains, water,

sewage, gas etc.

2. 'ention the ad*antages and the disad*antages of tunnel

:ns. :d*antages

. >a*ements inside the tunnel are protected from weathering and cost ofmaintenance is reduced2. Tunnels are totally protected from bomb attacks during wars

&. Tunnels may be sometimes more *iable than open cuts1. -ongestion problems in cities may be sol*ed to some e?tent by constructing

tunnels

". Gpen cut slip failures are totally eliminated3. Tunnels do not affect surface life and traffic during construction

#isad*antages

. Tunnels reuire more period for construction2. Special skills, technologies and euipments are needed in tunnel construction

&. Tunnel failures lead to serious problems during normal operations.1. Tunnels are sometimes more e?pensi*e

". >roblems due to pollution, seepage, rock fragment slipping, *entilation etc aremore acute in nature



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7''ention the circumstances under which tunnels are preferred than open cut:ns. The following are the situations which forces one to go for tunnels than open

cuts. 0hen the city is highly congested and demands rapid and unobstructed traffic

facility in the form of tube rails2. If acuisition of land for surface facility is costly

&. If the alternate route than a tunnel is circuitous1. 0hen water is to be supplied for power generation continuously from a higher

le*el to lower le*el in hilly areas

". Tunnels permit easy gradient inside the mountainous terrain and traffic

operations is easy3. Since tunnels are hidden structures below ground le*el, safe for strategic

routes7. If open cuts are prone to landslides

&. 0hat are the factors that go*ern the shape and si+e of a tunnel

:ns. The factors that influence the shape are

. 'aterial to be transported in the tunnel2. /?ternal pressure of forces to be resisted&. Soil type encountered

1. Si+e reuirement of tunnel depending on the purpose

The factors that depend si+e of the tunnel are

. =olume of the traffic to be handled if it is meant for automobile traffic2. Type of traffic like pedestrian, highway or railway

&. Si+e of the clear opening reuired all round the tunnel1. #rainage facility reuired in case of seepage of water percolation

". :rtificial *entilation to be adopted in case of long tunnels

1. 0hat are the common shapes adopted for tunnels #iscuss briefly their merits and

demerits

:ns. -ircular sectionA

This type of sections is commonly used for tube rails, highway tunnels, and sewer

lines to carry water for power generation.

:d*antagesA. This shape is economical as it gi*es ma?imum cross sectional area with

minimum perimeter2. 'ost suitable for non cohesi*e soils

&. Shields may be used for construction1. Ideal section for resisting both e?ternal and internal pressures

". Suitable for sewer and water lines3.

#isad*antages. ot suitable for roads and railways as it reuires filling to create flat base

2. -onstruction of circular shape is difficult



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Horseshoe sectionA

This is a combination of both circular and arch section as shown in the figure

:d*antagesA. 9etter pressure resistance due to cur*ed sides and arch action

2. 'ost suited for soft rocks&. Ideal for highways and railways, as it reuires little filling1. :lso suitable for sewage and water transportation

#isad*antagesA. #ifficult to maintain specified geometries

2. Reuires more centering work and time for completion

Rectangular sectionASuitable for hard rocks and may be constructed in R--. this is commonly used for

pedestrian traffic. #ifficult to construct and also costly

Segmental sectionA

Suitable for subways and na*igational tunnels as *ertical ele*ation is a*ailable.Segmental roof takes the *ertical load and transfers it to sidewalls. Suitable for hardrock and R-- lining in case of soft soil


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/ach of the abo*e has ad*antages and disad*antages during tunneling work. $sually

drilling boreholes along the proposed route is adopted for in*estigation. In soft soilaugers or split tube may be used for collecting samples. Sometimes core samples

may ha*e to be e?ca*ated by drilling short holes of diameter 8 to 28 cm. Thesamples obtained by abo*e methods should be identified properly for rock

classification, its thickness in strata, mineral composition, structure, hardnessstrength etc. based on the type of rock or soil encountered in the strata along thetunnel alignment, the type of tunneling, the necessity of grouting, method of

blasting, drilling method and pattern, mucking, safety measures may be thought off.

>. E2plain a method o# trans#er o# centerline into the tunnel and pro1iding

grade5:ns., the transferring of centerline from ground into the tunnel is a *ery important

one and should be done accurately, else the work started form either side of thetunnel would not meet at a common point. :ny de*iation in the centerline will cause

additional work and e?penditure. The arrangement for transferring the tunnelcenterline into the tunnel is as shown in the figure.

Two reference pillars are established on the ground as shown in the figure and

are R< established. Two plumb bobs each weighing 8 kgs are lowered into thetunnel shaft from the surface in two opposite faces of the shaft. The plumb bobs aresuspended by piano wires passing o*er groo*es cut on pipes fi?ed, across the mouth

of the shaft. The wire of each plumb bob is wound o*er a reel and released to thereuired length to the bottom of the shaft. If oscillation are to be pre*ented, the

plumb bobs are to be suspended in oil pail. The line ;oining these two piano wires isfi?ed and e?tended by a transit Theodolite placed in the shaft or to a point on the

roof of the heading and inclined on spuds fi?ed to the roof of the heading. :corresponding point is transferred on the other face also. The e?tension of these two

points is the centerline of the tunnels transferred from surface.



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>ro*iding grade in the tunnel

>rocedureA

. The transit Theodolite is placed on the center al line of the tunnel (ie, transfer

from surface) and the Theodolite is centered and le*eled properly.2. >oints 9 and - are located on tunnel wall by rotating the telescope through

8degrees&. ow the direction of telescope to get the points 9 and - as % and roduction of compressed air using air compressors is *ery easy

and simple.2. -ontrol and regulation of compressed air are easy.

&. Ideal for soft soils with water bearing strata1. -ontinuous working is possible with change in shift for workers

0?' /?plain with sketches shield method of tunneling.

:ns. This is an impro*ed method tunneling which could be used in soft soils.

The progress of work may be from mere 38cm per day to &78cm per dayand could be used for tunnels of si+e & to m.

Shield consists of a steel ring in circular shape of suitable diameterand with a tra*erse diaphragm. It also has the following parts like hood, tail,

cutting edges and propelling ;acks as e?plained below.HoodA Hood is the forward e?tension of the circular ring at the top and

affords protection to minors working in the forward direction.TailA Tail is made up of hea*y caste iron and forms rear sections which

pro;ects back little distance o*er the completed lining

-utting edgesA This is used to cut the earth during e?ca*ation. It is shiftedwith stiffness to protect it from breakage.>ropelling ;acksA These are used to propel the shield and are mounted on

center line of the central ring beam of the shield .the ;acks are of hydraulictype with hea*y propelling power and are eually spaced which causes

reaction against the completed lining and thus push the shield forward,cutting the soil.

>ortholes in the diaphragm are used to do permit the out flow of the muck.To o*ercome the resistance from soil, hori+ontal and *ertical bo? girders

stiffen the circular bo? girder.>rimary lining of caste iron is pro*ided for the tunnel section consisting of

channel sections of lengths "84 !8cm and ha*ing a minimum thickness of

2" mm.Steering the ;acksA operating ;acks propels the shield forward, which e?erts

thrust against primary lining immediately behind. The primary lining shouldbe erected first to withstand this thrust due to forward motion of the shield



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0@'0ith reference to hard rock tunneling, e?plain briefly the followingA a. 'ethods a*ailable and ad*antages

b. #rilling euipments used c. #rilling hole pattern

d. >recautions to be obser*ed:nsA depending on the si+e of the tunnel the following different methods are

a*ailable for hard rock tunnelingA

. 6ull4face methodA in full face method the entire cross section is attacked

at a time for completing tunneling operation. This method is usually adopted

for tunnels of small cross section and in rocks that self4support. Theseuence of operations like drilling, loading the holes with e?plosi*es and

detonators, blasting and mucking are done in seuence. it has the followingad*antages.

. It reuires minimum euipment and simple is operation.2. Simultaneous tackling of full face sa*es time.

&. :ll operations will be o*er in less time.1. Track for mucking could be laid once for all.

2. Heading and bench methodA in heading and bench method top headingand bottom heading are worked in seuence to complete the tunnelingoperation. 6irst top heading is drilled, loaded with e?plosi*es and blasted.

Then using this as bench or platform, same seuences of operations are

performed on bottom heading. This is repeated for further length of tunnel

and work is progressed. This reuired less uantity of e?plosi*es and brokenrock fragments might need support temporarily.



49/84

&. #rift methodA in this method a small heading of suitable si+e either ontop, middle or bottom is made and this drift is e?panded in remaining

directions as the case may be. /?pansion may be done either by widening orbenching depending on con*enience. The following figure gi*es the seuence

of drift method indicated by numbers.

The si+e of the heading should be sufficient to accommodate

tunneling euipment and the other machinery. 6reuent shifting of mucktrack may be a*oided by completing heading and bench to a short distance.

1. #rilling euipmentA The selection of proper drilling euipment depends on

si+e and depth of drill hold, hardness of rock, pro;ect si+e, terrain conditions,fissures in rocks etc. The following types of drilling euipments are a*ailable.

a. >ercussion drillsA The rock is broken by repeated impact by blowsb. :brasion #rillsA Rock is ground to small particles by aeration effect



50/84

of drilling bits, which rotate in the drill holec. 6ussion #rillsA G?ygen and flu? like kerosene are burnt at the tip of

blowpipe and flame de*eloped is directed against the rock to get atemperature up to 88c thus causing rock to flake off.

". #rilling patternAa. >yramidal patternA In pyramidal pattern four different types of cut

holes are used in combination to get ma?imum output. -ut holes are inclinedin words forming the side edges of a pyramid.

These holes are assisted by relie*ers spaced between them. /T 4(>enta /nythrital), R#M 4

(rapid detonating e?plosi*e) or TT (tri nitro taluene).

Safety measuresA



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. Rock protrusion should be remo*ed by scaling using hammers.2. Rock fragments loose and which does not fall should be properly propped.

&. 6irst aid, light and power lines should lines be properly a*ailable.1. :ll workers should be pro*ided with a metallic helmets.

". Steps to a*oid misfire, premature e?plosion and suffocation due to gases.3. Steps to detect une?ploded holes and its proper defusing.

7. 6iring face should be at least &88m away from e?plosion control point.!. 0et and slippery flooring should be a*oided.

40'0hat are pilot tunnels 0hat are ad*antages

:nsA to facilitate speedy completion of tunneling operation, a small tunnel is

dri*en parallel to the main tunnel as shown in figure and such tunnels arecalled pilot tunnels. 'ain tunnels and pilot tunnels are connected by cross

cuts as shown in the figure. >ilot tunnels are preferred when *erticalapproaches i.e., shafts are of high deep than hori+ontal approach.

:d*antagesA. -rosscuts and pilot tunnels may be used to store tools and

materials using tunneling work.

2. >ilot tunnels may be sometimes economical than *ertical cuts orshafts.

&. Luite safer than shafts.1. :fter completion of main tunnel, pilot tunnel may be used for

maintenance operation.

". -ould also be used for mocking operation during construction ofmain tunnel.

3. 'ay used for artificial *entilation.



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2". /?plain telescoping form of lining in tunnels.

:nsA usually the lining for tunnels is done separately for arch portion andwall portion in seuence. 9ut this has been replaced by single unit forms

known as telescoping form that are suitable for small tunnels only i.e., up to3 to ! m diameter. 6or bigger tunnels the sections becomes too hea*y for

handling and erecting. Telescoping form consists of a tra*eler mounted ontrack and has many ;acks to support ribs of steel sections so that backsection could be collapsed and mo*ed forward for ne?t use without

disturbing concreting.



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4


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-irport engineering

-1iation de1elopment

Introduction

The first attempt to fly in the sky was made in 8& and there after with insmall span of time aircrafts were used to transport both men and materials on alarge scale. :ircrafts were used during 6irst 0orld 0ar also between 14!.

Grgani+ations were formed to bring in standardi+ations in a*iation industry and

airport design to ha*e uniformity in the design practices. To ha*e positi*e andhealthy growth of a*iation industry in the country it is necessary to estimate the

future demand for air tra*el and to pro*ide suitable facility for air tra*elers. 9eforeany airport is designed and constructed it is necessary to consider all the aircrafts

characteristics that use the airport and design the facilities accordingly. It is alsoessentially to understand the definitions of a few new terminologies connected with

the airport and how each one is located at an airport for its proper use. Gne problemthe pilots normally face is the *isibility conditions and flights should be carried out in

accordance to stipulations.

0' E2plain brie#ly the history o# air transportation in general and India inparticular'

-ns$ The first flight in air was carried out by an :merican by name Gr*ille 0right on#ecember 7, 8& at %itty Hawk, orth of -alifornia in $S:. He flew through a

distance of &"m. The de*elopment of aircraft industry was *ery slow during 0orld0ar I period i.e. between 14!. 5ermany used to transport people from one

place to other in eppelin :ero planes. 6irst ;et flight was done on august 27, & in5ermany, manufactured by Heinkel :ircraft -ompany. The first international air

ser*ice between 6rance and Spain was started in !. :ir to ground communicationwas established in 2 which rendered air tra*el safer.

Te first air flight in India was made by Henry >iuet, a 6renchman from

:llahabad to aini in . In 27 ci*il a*iation department was established tode*elop aerodromes in the country. In 2 air ser*ices was commenced between

#elhi and %arachi . I &2 internal ser*ices was started by Tata :irways


56/84

7'%hat is the role o# ,-- and I--I in the de1elopment o# airport #acilitiesin India'

-ns$ :: is the abbre*iated from of ational :irports :uthority and was establishedon une , !3. This organi+ation manages all the domestic ci*il airports distributed

all o*er India. It manages the essential facilities that are necessary for safe landingand take off aircrafts at an airport. It also maintains international airports using

latest communication systems, radars etc reuired for air traffic control.I::I is abbre*iated form of International :irports :uthority of India. This as

established in :pril 72 to de*elop , construct and maintain the International air

ports in India i.e. at 'adras ,9ombay, #elhi and -alcutta. The ob;ecti*e of forming

this organi+ation was that, with the introduction of big si+e air crafts to air traffic inIndia in serious congestion problems and delay occurred at airports resulting in time

loss. To recommend suitable measures, go*ernment of India appointed a -ommitteeunder the chairmanship of 'r. .> Tata to suggest suitable measures for the said

problem.

8' List the 1arious elements o# an airport and e2plain them with neatsketch'

-ns$ The following are the *arious elements of an airport as shown in the abo*e

figure

)Runway 2) Ta?iway &) Hanger 1) Terminal building ")


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This is the ma?imum radius with which the aircraft can take a turn in sky or space.This depends on minimum speed which an aircraft can sustain in space during

circling. It also depends on weather conditions as gi*en below.) Small aircrafts under =6R conditions4.3kmSunday, :pril 7, 288"

2) 9ig aircrafts under =6R conditions 4&km&) >iston engine aircrafts under I6R conditions4&km

1) et aircrafts under I6R conditions4!8km'ore than this distance should be maintained between two nearby airports so

as not to ha*e interference during simultaneous circling at both the airports. If

spacing can not be maintained then both airports should operate in coordination.

Turning radius$

This is the minimum radius with which the aircraft can take turn on ground. This isreuired to be pro*ided at ;unction of runway ta?iway and to establish the position of

aircraft an apron and inside the hanger. Turning radius may be determined ase?plained below.

a line is drawn through the a?is of the nose gear when it is at its ma?imumangle of rotation of front wheels as indicated in the figure. This line should intersect

the line drawn through the a?is of the rear wheel assembly and this is called centre

of Rotarian. The distance of the farther wing tip from the centre of rotation is theminimum turning radius .To minimi+e the wear due to sharp turning angle is usuallykept to a ma?imum *alue between "8438.

uel spillage$

6uel spilling or lubricants may take place in hangers or refueling points hear apron.This cannot be totally a*oided or eliminated but could be minimi+ed by some

remedial measures. This problem is more serious with bituminous type of pa*ementssince bitumen is soluble in high grade petrol used for aircraft.

Cet blast$

et blast e;ects high *elocities of e?haust gases at an *elocity of up to &88kph. This

causes lot of incon*enience to the passengers boarding or alighting aircrafts. 9lastfences or detectors may be constructed to reduce the effect of ;et blast. et blast

may erode the bituminous surface of pa*ement.

,oise$et aircrafts make noise than other type of aircrafts during landing and take off. The

noise le*el is more during takeoff than landing. :lso noise le*el is more in old type of

aircrafts and affords are in progress to reduce noise. To o*ercome the problem ofnoise o*er a city is to orient the runway from de*eloped part of the city.

Runway length #or take o## and landing$

6or each type of aircraft the manufacturer will ha*e gi*en the basic runway lengthreuired during landing, takeoff or in case of engine failure conditions. This length

should be increased for pre*ailing condition at the airport. 9asic length of runwaydepends on characteristics of the aircraft.



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&) >ossibility of impro*ing the e?isting airport.1) ew airport planning.

The abo*e mentioned steps should be followed carefully and correctly.

step06uture air traffic pro;ection should be based on estimated demand for air

tra*el depending on rate of growth of economy, industrial de*elopment ,populationgrowth, increase in percapita income etc. this data should be pro;ected for ne?t "428 years of planning period. The future air traffic prediction depends on correct

pro;ection of past data.

step4

The possibility of de*eloping the e?isting airport reuires through study for theincreased air tra*el demand. #ata regarding adeuacy of approaches for the

airport ,capacity to handle the peak hour traffic for runways and connecting ta?iways,facilities at terminal building and apron to cope with increased or anticipated

demand.

step7

If the afore said considerations pro*e that the e?isting airport is inadeuate for thee?pected air traffic demand then the possibility of impro*ing the capacity of e?istingairport should be studied with regards to e?tension of runway, either new or parallel

and impro*ing ta?iway for high speeds, increased or new facilities at the terminalbuilding and impro*ing the air traffic control facilities at the control tower.

step8

6rom the earlier steps, if it is not possible to handle the air traffic in all aspects thenit is ine*itable to propose a new airport to cater to the pro;ected demand of air

traffic.The following additional information or data may be considered for the future

airport to be de*eloped.

) >eak hourly *olume of air traffic to be handled.2) -haracteristics of aircrafts that use the airport presently and in near future.

&) Terminal facilities for passengers, baggage, cargo, aircrafts landing, aircraft takeoff and ser*icing facilities etc.

7'List and e2plain the 1arious #actors to be considered in the design and lay

out o# airport'

-ns$The following factors, which influence the airports site selection, should be

thoroughly studied.Regional plan

The selection of site for an airport should be such that it fits well into the regionalplan thus forming an integral part of the national network of airports. The si+e of the

airport and its planning should be so determined to cope with the de*elopment of theregion under considerations.

-irport useormally airports constructed either for ci*ilian purposes or military use. The airports

are taken o*er and used for defense purposes during war times and hence the designof airports should ser*e dual purposes.

Pro2imity or nearness to other airportsSufficient separation clearance should be a*ailable between two nearby airports so

that the landing and take off in on airport does not interfere with such operations in



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other airports. This depends on air traffic *olume, type and si+e of aircraft, air trafficcontrol facilities installed *isibility conditions etc. The following are some of the

recommended minimum spacing to be maintained for planning purposes dependingon *isibility conditions.

:ircraft si+e N type =isibility Separation clearance in km

Small =6R &.29ig =6R 3.1>iston engine I6R 2".3

et aircrafts I6R 38

round accessibility

The airport site should be near to the city so that it is easily accessible. The mainob;ecti*e of choosing air tra*el is to sa*e time in tra*el. Hence airport should be

located along a highway where uick con*eyance is a*ailable to reach within areasonable time. :lso the airport site should ha*e well connected network of roads to

reach it.

Topographical #eatures

These may include the general terrain, undulations, hill locks, streams, etc. $sually aele*ated ground may be preferred for airport site because of the following reasonsA

) -onsistent wind *elocity2) 'inimum number of obstructions in approach and turning +one in the form of tall

structures like transmission towers, high rise buildings etc.&) Terrain facilitates natural drainage thus cutting down cost of drainage structures.

1) /nhanced *isibility on hill top because fog usually settles in *alley portion.

+bstructions$:ny structures like tall building ,raised ground ,tall trees, transmission towers

become ha+ardous for air na*igation, depending on at what distance the ob;ect is

situated and its height with respect to the airport reference point. It is preferable tolocate the airport in general at a place where less number of obstructions is present

along approach path.

:isibility$>oor *isibility may be due to the presence of fog or smoke o*er the airport site.

Smoke may be emitted by some type of industries which when passes o*er the air

port site reduces the *isibility .Hence such industries should be curbed by suitablelegislation. To reduce the problem of *isibility due to industrial acti*ities the airport

site should be located on leeward side of wind direction

%ind$0ind data at a airport site should be collected for minimum period of "yrs and

preferably for 8 yrs period. 0ind parameters like direction duration and intensityshould be recorded for the said period and runway should be oriented accordingly. :s

far as possible the wind data collection centre should be an open field without hilllocks surrounding.

,oise nuisance$

The problem of noise nuisance is more acute in case of ;et aircrafts particularlyduring takeoff. Hence runway should be oriented along less de*eloped part of the city

and along approaches. 6urther de*elopment of industries or industrial centers should



62/84

be curbed by suitable laws. Sometimes preferential runways are constructed tominimi+e noise nuisance as shown in the following figure.

In the figure the pre*ailing wind runway is pro*ided long thickly populated +onewhich is not ad*isable. To a*oid this one more runway as indicated in the figure may

be pro*ided as this reduces the noise nuisance o*er the city. This runway is calledpreferential runway which is used only if wind permits to use it.

radingD drainage and soil characteristics$5rading means the operation in*ol*ed in earthwork like cutting and embankment for

the construction of *arious airport elements at the airport t site. Sometimes grading

plan influences the layout of an airport. :s far as possible *alley portion should bea*oid reducing the chance of flooding during rainy season. >er*ious soil is preferred

since the rain water easily percolates resulting in less surface flow. Thus reducing thecist of drainage structures .The thickness of pa*ement also depends on type of soil

and its properties which has direct bearing on cost of airport .Some percent of clayas binder is preferred in the soil.

Scope #or #uture de1elopment$

The site area should be large enough to satisfy the future needs of an airport which

may be in the form of e?tension of runway in either direction, ta?iways ande?pansion of terminal building and other facilities at the airport without additionalacuisition of land .ooming laws should be strictly implemented to check the

construction of any type of high rise buildings which may be ob;ectionable from airna*igation point of *iew.

-1ailability o# essential utilities #rom town$

The utilities or ser*ices may be in the form of electricity, telephone, f facilities, watersupply, sanitary system and fire fighting should be easily a*ailable from city or town.

9ecause these utilities if pro*ide e?clusi*ely for airport would be costly as creatingsuch facilities separately on indi*idual basis is e?pensi*e.

Economic consideration$The *arious cost components in*ol*ed in the construction and de*elopment of airport

are cost of land acuisition cost of earthwork, drainage structures, compensation forha+ard remo*al, parking facilities at airport, airport lighting, cost of terminal building,

construction of roads etc. has to be worked out correctly. The o*erall construction,maintenance and operation of an airport should be minimum for a site under

consideration .Howe*er the economy of the airport could be decided only if alternate

proposals are worked out.


63/84

,umber o# runways and connecting ta2iways$

If the airport is pro*ided with more number of numbers of runways, thecapacity of airport with two runways would be more than with a single runway.

:ircraft characteristic that uses the airportASmall si+e aircrafts with less number of seating capacity reuire less runway time

than the big si+e aircrafts. Hence the airports ser*ing smaller si+e aircrafts would bemore than the airports ser*ing big aircrafts.

:isibility and weather conditions$

If the *isibility conditions is good at the airport then =6R conditions e?ist, ob*iouslythe capacity of the airport would be higher. If the weather is foggy or raining, then

*isibility at the airport would be poor and the aircrafts ha*e to switch o*er to I6Rsystem during landing operation .9ut the capacity of airport under I6R conditions is

*ery less.Gbstruction surrounding the airportA

Gbstruction in the form of transmission tower, high4rise buildings or any othermanmade structures may pose problem for safe air na*igation and would reduce the

airport capacity.

Loading space at apron$-ongestion may occur due to lack of enough space at apron near terminal building

which is mainly used for loading and unloading of passengers, baggage and cargo.The congestion may result in delay to the departing aircraft reducing airport capacity.

a*igation aids a*ailable at control towerASophisticated instruments should be a*ailable to the aircraft controller to control

aircrafts at the airport which finally affects the airport capacity. This system reducesthe delay in landing at the airport.



64/84

R,%-3 "ESI,

Introduction$

The basic runway length for the aircraft may be found out for standard & cases and

the highest among the & *alues should be taken in to consideration for designing therunway length for the airport. This basic runway length needs to be corrected forpre*ailing field conditions since basic runway length is for ideal site conditions, which

do not e?it in reality anywhere. This basic runway length needs correction for

ele*ation, temperature and gradient as per the site conditions. The runway should be oriented along pre*ailing wind direction at the airport. This

may be determined by plotting the wind data along all the 3 directions. 6rom windrose diagram it is possible to find the best direction for the runway at an airport site

and also it is possible to find the percentage of time during which the runway couldbe safely be utili+ed for landing and takeoff of aircrafts considering cross wind

component at the site. -lassification of airports is needed to ha*e uniformity in design standards all

o*er the world. It is also necessary to study runway configuration to know the

capacity of the airport.

0' %hat is the meaning o# runway orientation5

-ns$It may be defined as aligning the runway along pre*ailing wind at the airport

site. Takeoff against wind would gi*e better uplift to wings and landing against windreduces the braking distance for an aircraft. :part from wind direction practical

considerations like obstruction along approach path like towers, high rise buildingsetc, e?cessi*e earthwork or places of public assembly make the planners to de*iate

the runway away from pre*ailing wind direction.

4.E2plain the meaning o# cross wind component and its e##ect on aircra#ts'

-nsA 0ind parameters such as direction, duration and intensity keep changing with

respect to time i.e. hour to hour, day to day etc. 0ind blowing at an angle ..... 0ithrespect to centre line of runway generates cross wind component which acts at right

angles to the centre line of the runway. The *elocity = at an angle....may be split upin to hori+ontal component =cos....and *ertical component i.e. cross wind

components =sin...The effect of this cross wind component is to cause drift of the

aircraft that is likely to land along centre line of the runway.

Problem0$6ind the cross wind component for a wind *elocity of "8kph acting at an

angle of &" degree with respect to hori+ontal. If sible cross wind component is2"kph. 6ind whether the runway could be safely utili+ed for airport operation.

Sol$-ross wind componentB *sin44

B"8 sin &" B2!.3! kph

Since the allowable crosswind component in 2"kph the runway cannot beutili+ed for landing operation as pre*ailing cross wind component is 2!.3!kph



65/84

7'%hat does u understand by the term wind co1erage5

-ns$The percentage of time in year during which the crosswind component at anytime remains with in the specified limit is called co*erage. It is designated by

percentage ./?ample "K wind co*erage indicates that the percentage of time in ayear during which the runway could be safely utilised for landing and take off is ",

remaining "K of time the cross wind component may e?ceed the permissible limit.6or e?ample for *ery big airports the wind co*erage should be as high as !K withan permissible ports the wind component of &"kph .Remaining 2K of the time the

crosswind component may cross the limit making it difficult for landing or take off

operation.

8'%hat is a wind rose diagram5 E2plain its application'

-ns$>lotting of wind direction duration and intensity graphically to a suitable scale is

called wind rose diagram. /?ample wind blowing with a *elocity of 1"kph at an angleof &8 with respect to north for !K of time in a year may be plotted .Here the wind

parameters are

=elocity, =B1"kph:ngle of wind blow B &8 with respect to north#uration B!K of time in one year

The abo*e data may be graphically represented.In the accompanying figure the wind is blowing at &8 with respect to north

and usually wind blowing in a sector of 22F2 i.e. .2" to left plus .2" to the rightis considered as wind blowing in that particular direction as indicated in the figure 2.

$sually wind rose diagram is used to find the percentage of time in a year therunway could be safely utili+ed for airport operation.

The following 24types of wind role diagrams may be plotted.) Type A indicating direction and duration

2) Type 2A indicating direction and intensity of wind.

B'%hat is calm period5 Illustrate suitably'

-ns$If the percentage of time in a year during which the wind *elocity is less than

3.1kph is called calm period.To find the calm period, add all percentages of time the wind blowing in

different directions and this sum deducted in 88 gi*es the calm period in

percentages./?ampleA If the sum of percentages of time the wind blowing in all the 3 directions

is 2K, then calm period is obtained as(8842)KB!K. This calm period *alueshould be added to the total co*erageEs.



66/84

;< or the #ollowing data plot type 0 wind rose diagramD e2plain theprocedure and #ind the orientation o# runway and percentage o# wind

co1erage'

-ns$

%ind direction "uration o# wind

in percentage o#time

%ind direction "uration o# wind

in percentage o#time

, >'7 S ?'lace this transparent paper on the wind rose diagram such that both parallellines pass tangentially to the second circle as shown in fig 1.

(3) Irrespecti*e of the position of transparent paper the first set of *alues are fullyco*ered under the parallel lines and the third set of *alues are too low *alue and

does not contribute much to the sum of total co*erage. Hence the paper should be

rotated in such a way that ma? is in between two parallel lines. This reuires therotation of paper either in clockwise or anticlockwise direction or at a particularposition would gi*e ma?imum co*erage.

(7) ow find the sum of all partial and full co*erageEs to get the total co*erage andadd calm period of 1."K to this to get full co*erage. The total co*erage is the sum

calculated as followsA(:) 7.3 @ ".& @ 2.! @ .8 @ 8.8 @ 8.& @ 1.3 @ ". @ . @ 3. @ &. @ 8. @ 8."

@ 8.2 @ ".8 @ 1.&B "!.!!K (sum of all the *alues)

(9) 2.! @ 2.3 @ 8.3 @ 8. @ .2 @ &.8 @ 1.1 @ &.8 @ 8.& @ 8.2 @ 8.7 B 3.K(Sum of full and partial

co*erageEs)

(-) 8.1 @ 8 @ 8.1 @ 8.8! @ 8.2 @ 8.2 B .2!K(#) -alm period B 1."K

.Q. Total wind co*erage B "!.! @ 3.! @ .2! @ 1." B.1!K



69/84

;?' "e#ine basic runway length' List and e2plain the assumptions made'

-ns'The basic runway length may be defined as the length runway reuired forlanding or takeoff under the following assumed ideal conditions.

() :irport is located at mean sea le*el i.e. +ero ele*ation.(2) Temperature at the airport is constant or standard "-

(&) Runway is le*el in the longitudinal direction i.e. +ero gradient.(1) o wind is blowing on the runway.

(") :ircraft is loaded to its full capacity.(3) o wind is blowing in the en route direction.

(7) /n route temperature is constant.

E2planation #or the assumptions$ It is assumed that the airport is at +ero ele*ation and any change in altitude at a

place is suitably incorporated in the form of correction to basic runway length. Thelength of runway reuired is more at higher altitude since air density decreases, thus

increasing the length of the runway for takeoff. The effect of increase in temperatureis same as that of increase in ele*ation hence any increase in temperature other than

standard temperature of " - is taken care by applying correction. The assumption that the runway is le*el in the longitudinal gradient signifies that

any change in gradient increases the length of runway reuired for landing ortakeoff. :ircraft reuires more length of runway during takeoff a positi*e gradient.

0hen no wind is blowing on the runway indicates the worst condition for landingand takeoff. o wind blowing on runway reuires more length of runway since wind

blow could be effecti*ely used during landing and takeoff reducing the length ofrunway reuired.

The aircraft reuires more length of runway during the takeoff when it is loaded

to its full capacity or rated capacity and this is the worst condition in the field foraircraft on the runway.

If the temperature change or wind blows in en route direction pre*ails, it alters

fuel reuired for the trip.



70/84

;@' E2plain the 7 cases considered in arri1ing at the basic runway length #or

an airport'

-ns' The basic runway length reuired for an aircraft depends on its performancecharacteristics under the following &4cases. :mong the &4cases highest *alue of basic

runway length should be pro*idedA

() ormal landing case

(2) ormal take off case

(&) Gne engine failure case(1)

,ormal landing case$In normal landing case the length of the runway reuired for safe landing from a

height of "m to a stop point making use of 38K of total landing distance pro*idedthe e?tra 18K runway pro*ided is only for safety.

,ormal take o## case$In normal take off case it is assumed that the aircraft accelerates from one end of

the runway, lifts off and reaches a height of 8." m abo*e the runway. -lear way is

pro*ided at the other end of the runway for safety. This width should be minimum"8m.+ne engine #ailure case$

This case may reuire either a stop way or a clear way or both depending on thesituation. Stop way is pro*ided at the end of the runway protruding in to the clear

way. Stop way may be used for decelerating the aircraft.In this case if the engine failure occurs at less than the designated speed for the

aircraft (i.e. ground sped before liftoff) then the aircraft could be decelerated andbrought to stop making use of stop way. This is called aborted takeoff. If the engine

fails at a speed more than the designated speed, then there is no option for the pilote?cept to take off and take a turn in turning +one, land again for a normal takeoff.

;0A' E2plain the meaning o# balanced runway or #ield concept'

-ns'

In case of engine failure, the failure speed is so selected by the manufacturer ofthat the length in which the aircraft accelerates and takeoff distances are eual. Thus

the basic runway length is considered based on balanced field concept or balanced

runway length. This minimi+es the runway length for aircrafts.

;00' E2plain the correction re=uired #or basic runway length'

-ns' The basic runway length of runway determined by &4methods is for ideal

conditions. If any change is assumed conditions pre*ails, then suitable correctionsha*e to be applied for basic runway length at the prescribed rate as followsA

(0) !orrection #or ele1ation$

It is assumed that the runway is at 'S


71/84

(4) !orrection #or temperature$

The effect of temperature increase is same as that of ele*ation. The following factorsto be kept in *iew while applying correction.

(a) The standard temperature at airport is "-.(b) This standard temperature decreases as the ele*ation increases at the rate of

8.883" -Fm increase in ele*ation.(c) 9ased on the abo*e two factors find the new standard temperature at the airport.(d) :irport reference temperature should be determined by the following formula for

the hottest month of the year.

:RT B Ta @ (Tm4Ta)F& 0here :RT B :irport reference temperature c

Ta B monthly mean of a*erage daily temperature - TmB monthly mean of ma?imum daily temperature-

Hence :RT may be defined as the monthly mean of a*erage daily temperature(Ta) plus one third of this temperature to monthly mean of ma?imum daily

temperature (Tm).(e) rise in temperature is gi*en by difference of :RT to new standard temperature.

:s per I-:G for e*ery - rise in temperature abo*e standard temperature the

runway length that is corrected for ele*ation should be further increased by K.

(7) !heck #or total correction #or ele1ation and temperature$

:s per I-:G guidelines the total correction for both ele*ation and temperaturefor basic runway length should not be more that &"K of basic runway length.

i.e. if < is the basic runway length and '?

48



72/84

Sol$6rom the abo*e data it is clear that 'ay is the hottest month of the year.

.Q. Ta B &&.8 and Tm B &7."

.Q. :RT B &&.8 @ (&7." 4 &&.8)F& B &1." - .Q. :RT B &1."-

Problem 7$

-t an airport Ta 7BF! G Tm 80F! and airport has an ele1ation o# @AAmabo1e &SL' ind the increase in temperature #or which correction is

re=uired'

Soln$ Ta B &"- , Tm B 1-

:RT B Ta @ (Tm 4 Ta) F & B &" @ (1 4 &) F &

:RT B &7-

ew standard temperature at the airport isB " 4 8.883" 88 B " 4 ".!" B ."-

Hence ride in temperature is (&7 4 .")- B 27.!"-

Problem 8$

The #ollowing data pertains to the pro#ile o# a ground selected #or runwayconstruction at an airport' I# the chain length is 7AmD #ind the e##ecti1e

length o# the runway' !hainage grade H

A 4A J0'A4A 7B A'B

7B BB A'4

BB >A J0'B >A @A JA'B

@A 04A A'7

Soln$ :ssume R< at beginning as 88.88

-hainage,-hains #istance, pointto point

5radientpercentage

#ifference inheight , mts

R< mts

8 4 4 4 88.88

8428 388 @3 83.88

284&" 1"8 48." 2.2" 8&.7"

&"4"" 388 48.2 4.2 82."

""478 1"8 @." @3.7" 8.&8

7848 388 @8." @& &.&8

8428 88 48.& 42.7 8.38

'a?imum difference in ele*ation is (&.& 4 88) B &.&m

Total length of profile B 28 &8 B &388m.Q. /ffecti*e gradient B (&.&& F &388) 88 B 8.&31K

Problem B$

Transportation E

transportation engg 2 cv63

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