Transportation engineering 2

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Prepared by R.Vijayakumar, B.Tech (CIVIL), CCET, Puducherry

TRANSPORTATION ENGINEERING – 2

UNIT – 1

1. What is meant by zonal railways?

The entire railway station has been divided into nine zonal railways

having different territorial Jurisdictions which are responsible for all

management and planning of works.

2. What are the advantages of railways?

Railways have helped in the mass migration of the population.

The role of railways during emergencies in mobilizing troops and war

equipment has been very significant.

Railway has made it easier to reach places of religious importance.

Railways provide a convenient and safe mode of transport for the

country.

Land values have increased due to industrial development which

ultimately results in the increase of national wealth.

Speedy distribution of finished product is achieved through railways.

Environment friendliness

Higher safety and energy efficiency.

3. What are the different types of gauges?

Broad gauge

Metre gauge

Narrow gauge

Feeder track-gauge (or light gauge)

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4. Define gauge of track.

The gauge of a track in India is measured as the minimum distance

between the inner or running faces of the two track rails.

5. Enumerate the various factors that govern the selection of various types

of gauges.

Cost of construction

Volume and nature of traffic

Development of the areas

Physical features of the country

Speed of movement

6. Define formation.

Formation is the prepared sub – grade ready to receive the ballast.

7. Define ash pits.

These are long masonry pits built longitudinally under the track for

discharging of ash from locomotives.

8. Define drop pits.

They are rectangular deep pits in which wheels of the locomotives are

taken out for repairs.

9. Define examination pits.

These are rectangular masonry lined pits, larger than ash pits in size,

and are provided in locomotive yards to examine the engine from

underneath.

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10. Define inspection pits.

These are the pits, similar to ash pits, but of larger dimensions

provided in loco yard for inspection of the engine from underneath.

11. What is meant by cutting?

When the ground has to be cut, it is called cutting. Cutting is termed

as shallow cutting when the depth is 3m or less and is called deep cutting

when the depth is more than 3m.

12. What is meant by embankment?

The raised structure above the ground level for carrying the railway

track is called embankment. When the height of the embankment is more,

the side slopes are steepened for better stability of slopes.

13. What are the two types of continuous automatic brakes?

Compressed air brakes

Vacuum brakes

14. What are the objectives of “Reconnaissance Survey”?

To acquire the knowledge of physical features of the country like the

rivers, valleys, cultivated lands, forests, hills, existing roads, canals,

etc., for selecting the proper position of alignment

To collect geological information regarding the following points are

nature of soil, surface formation of the ground, dip of the existing

rocks and hill slopes

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To collect the information regarding availability of constructional

materials, labour and sources of water as permanent facilities for the

proposed alternative alignments

To have an idea about possible alternative alignments

To have an idea of rivers and streams which may cross the proposed

alignments for determining suitable bridge sites and their bridging

requirements

To locate various control points or obligatory points for getting an

idea from where the alignment should pass and from where the

alignment should not pass

To decide the maximum gradient and curvature for proposed

alignment

To prepare rough estimates for different proposed alignments to know

most economical, safe and efficient alignment

15. What are the various resisting forces which a locomotive has to

encounter before starting a train and to keep it in motion?

Train resistances

Resistances due to track profile

Resistances due to starting and acceleration

Wind resistance

16. What engineering surveys are to be conducted for choice of route for a

new railway line?

Traffic survey

Reconnaissance survey

Preliminary survey

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Detailed survey

17. What are the details to be taken on reconnaissance survey?

Accurate topography of the country.

Towns, railways, river crossings, tunnel sites, etc.

Geological characteristics of the soil of the area affecting foundations

for bridges and stability of the project line.

Width of waterway required for rivers and drainages.

Maximum flood levels of the intercepting natural drainages.

Availability of building materials and labor.

Probable radii of the horizontal curves.

The total length of the route.

Amount of expected earth work.

The approximate cost of construction of each probable line.

18. What are the factors to be kept in view during reconnaissance survey?

The reconnaissance survey should be done for the whole area

influencing the railway project, particularly for wide belt on either

side of the general direction of alignment rather than for a line only

All the possible alignments marked on the map, during map study,

should be examined and improvements made if necessary

All the intermediate points should be very carefully fixed so as to

attract maximum traffic and hence more revenue; less construction

problems and hence economy in construction, to achieve this, the

following points should be considered:

Rivers should be crossed at right angles and those places where

approaches are sound and approach banks are not very high

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Mountain passes should be so located that they could be

reached without steep gradients or deep cuttings

A tunnel may also be proposed if very economical

The station site should be located within 2km from the existing

town or village and at level stretch of land.

19. What are the instruments used in preliminary survey?

Theodolite – for traversing

Tacheometer – for plotting main features

Dumpy level – for drawing the longitudinal sections and cross

sections

Plane table – for plotting interior details

Prismatic compass – for magnetic bearings of routes and main points

20. Write a brief note on Indian railways.

In the nineteenth century before the introduction of railways, India

was a country with extremely poor means of communications and without a

well-developed system of transport. Early efforts for the introduction of

railways may be traced back to the year 1832 when construction of a railway

line between madras and Bangalore was contemplated, though it did not

materialize then.

21. What is a dynamometer car and what is its purpose in railways?

This car gives information regarding the condition of track. It is

placed between the locomotive and train. It plots automatic graphic record

called ‘Hallade Chart’ of the track profile. The recording equipment is

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called ‘Hallade recorder’. This test on the track condition with

Dynamometer car is usually conducted every six months.

22. What is EDM?

Electro-magnetic Distance measurement is a general term used

collectively in the Measurement of distances applying electronic methods.

23. List the uses of Remote sensing data.

Gives a bird’s eye view of large areas

Ground condition can be defined with a combination of satellite

images and Topographic maps

24. Write the advantages of flat footed rails.

Initial cost is less

Higher strength, stiffness and rigidity

No chairs required

Simple arrangements at points and crossings

Less liable to form kinks

Load distribution is high

25. What are the merits and demerits of bull headed rails?

MERITS:

They keep better alignment and give more solid and smoother track

The rails are easily disconnected from sleepers as they have no direct

connection with the latter

The heavy chairs with larger bearing on sleepers give longer life to

wooden sleepers and greater stability to the track

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DEMERITS:

They require additional cost of iron chairs

They have less strength and stiffness

They require heavy maintenance cost

26. What do you understand by the term “Buckling of rails”?

Buckling means the track has gone out of its original position or

alignment due to prevention of expansion of rails in hot weather on account

of temperature variations. This buckling may take place on tangent lengths

and at curves.

27. What is the importance of railways?

The railways have their greatest utilization in the transport of large

volumes of heavy and bulk commodities over long distances and in very

long distance journeys of passengers with safety, comfort and convenience.

28. What are the advantages of “Coning of wheels”?

To reduce the wear and tear of the wheel flanges and rails, which is

due to rubbing action of flanges with inside faces of the rail head

To provide a possibility of lateral movement of the axle with its

wheels

To prevent the wheels from slipping to some extent

29. Define kinks of rails and write its causes and effects.

When, the ends of adjoining rails move slightly out of position,

“shoulders” or “kinks” are formed.

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CAUSES:

Loose packing at joints

Defect in gauge and alignment

Defect in cross level at joints

Uneven wear of rail head, where kinks are formed at joints.

EFFECTS:

These kinks cause unpleasant jerks in vehicles passing over them

Due to uneven wear of rail heads, these kinks appear at places other

than the joints and obstruct the smooth running of trains

A series of kinks are seen at curves due to which defect in gauge,

alignment and camber may occur. This involves, sometimes, a

serious risk in turning operations of trains.

30. Define sleepers.

Sleepers are members generally laid transverse to the rails on which

the rails are supported and fixed, to transfer the loads from rails to the ballast

and sub-grade below.

31. What are the functions of sleepers in the track?

To hold the rails to correct gauge.

To hold the rails in proper level or transverse tilt.

To act as an elastic medium in between the ballast and rails to absorb

the blows and vibrations of moving loads.

To distribute the load from the rails to the index area of ballast

underlying it or to the girders in case of bridges.

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To support the rails at a proper level in straight tracks and at proper

super elevation on curves.

32. What are the requirements of sleepers?

The sleepers to be used should be economical

The fittings of the sleepers should be such that they can be easily

adjusted during maintenance operations such as easy lifting, packing,

removal and replacement

The weight of sleepers should not be too heavy or excessively light

The design of sleepers should be such that the gauge, alignment of

track and levels of the rails can be easily adjusted and maintained

The sleeper design and spacing should be such as to facilitate easy

removal and replacement of ballast

The sleepers should be capable of resisting shocks and vibrations due

to passage of heavy loads of high speed trains

33. Define sleeper density.

Sleeper density is the number of sleepers per rail length and it is

specified as (M + x or N + x), where M is the length of the rail in metres (N

is the length of rail in yards) and x is a number, varying according to the

following factors and is fixed by the railway board for various axle loads.

The factors governing the sleeper density are,

Axle load and speed

Type and section of the rails

Type of ballast and ballast cushion

Type and strength of sleepers

Nature of foundation

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34. Write a small note on the need of construction of a new railway line.

Strategic reasons

Connecting trade centers

Developing a backward area

Shortening the existing route

35. Define track alignment.

The direction and position given to the centre line of the railway track

on the ground is called the track alignment.

36. What is meant by track circuit?

The length of the track, which is connected by electric circuit to signal

cabin, block telegraph apparatus, etc. required for indication of light or bell,

is called track circuit.

37. List the factors influencing the selection of a good railway track

alignment.

Obligatory or controlling points

Position, amount and type of traffic

Gauge selection

Geometric standards

Topography of the country

Economic considerations

Other considerations

38. What are the three stages of construction of new railway track?

First stage: Earth work – formation and consolidation

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Second stage: Plate laying – laying of a railway track

Third stage: Laying of ballast on the track

39. Write the requirements of a good rail alignment.

Purpose of the track

Feasibility

Economy

Safety

Aesthetic aspects

UNIT – 2

1. Define permanent way.

The combination of rails fitted on sleepers and resting on ballast and

sub-grade is called the railway track or permanent way.

2. What are the requirements of ideal permanent way?

The gauge should be correct and uniform

The rails should be in proper level

The alignment should be correct

The gradient should be uniform and as gentle as possible

The radii and super elevation on curves should be properly designed

and maintained

Drainage system must be perfect for enhancing safety and durability

of track

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3. What is meant by capacity of a railway track?

Capacity of the track is the number of trains that can run safely on a

track per hour.

4. What is meant by hauling capacity?

Hauling capacity of locomotive is the total load which can be hauled

by it. It indicates the power of the locomotive.

5. What are the three types of rails?

Double headed rail

Bull headed rail

Flat footed rail

6. What do you understand by the term “Ballast”?

Ballast is the granular material usually broken stone or brick, shingle

or kankar, gravel or sand placed and packed below and around the sleepers

to transmit load (due to the wheels of the train) from sleepers, to formation

and at the same time allowing drainage of the track.

7. What are the functions of ballast?

It transfers the load from the sleeper to the sub-grade and distributes it

uniformly over a larger area of the formation

It holds the sleepers in position and prevents the lateral and

longitudinal movement, due to dynamic loads and vibrations of

moving trains

It imparts some degree of elasticity to the track

Provides effective drainage to track

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Act as a medium for provision of super elevation in curves of railway

tracks

8. What are the requirements of good ballast?

It should be able to withstand hard packing without disintegrating

It should not make the track dusty or muddy due to powder under

dynamic wheel loads

It should allow for easy drainage with minimum soakage and the

voids should be large enough to prevent capillary action

It should offer resistance to abrasion and weathering

It should retain its position laterally and longitudinally under all

conditions of traffic, particularly on curves, where it should be able to

prevent transverse displacement of sleepers

It should not produce any chemical action with rail and metal sleepers

The size of stone ballast should be 5cm for wooden sleepers, 4cm for

metal sleepers and 2.5cm for turnouts and crossovers

The materials should be easily workable by means of the implements

in use

9. What are the different types of “Ballast”?

Broken stone

Gravel or river pebbles or shingle

Ashes or cinders

Sand

Moorum

Kankar

Brick ballast

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Blast furnace slag

Selected earth

10. What are the components of a permanent way?

Rails

Sleepers

Ballast

Formation

11. What is creep of rails?

Creep is defined as the longitudinal movement of rails with respect to

sleepers in a track.

12. What are the causes of creep?

Ironing out effect of moving wheels on waves formed in rails

Tendency of wheels to push rails forward and backward during

braking, acceleration, deceleration and running

Impact when wheels run on ends of rails

13. What are the effects of creep?

Sleepers get out of square and consequently gauge and alignment get

distorted

Rail joints get opened out, resulting in failure of fishplates and bolts

The joints are continuously jammed

Points and signals fails

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If any rails is removed from the track for any purpose, it becomes

difficult to fix it again at proper position because by the time gap

becomes too short or too long due to creep

14. What is meant by coning of wheels?

The distance between the inside edges of wheel flanges is generally

kept less than the gauge of the track. So there is a gap between the wheel

flanges and running edges of the rails, nearly equal to 1cm on either side.

Normally, the thread of wheels is absolutely dead centre of the head of the

rail, as the wheel is coned to keep it in this central position automatically.

These wheels are coned at a slope of 1 in 20.

15. What are the various types of sleepers used in Indian railways?

Wooden sleepers

Metal sleepers

Cast iron sleepers

Steel sleepers

Concrete sleepers

Reinforced concrete sleepers

Pre-stressed concrete sleepers

16. What are the different types of rail joints?

Supported rail joint

Suspended rail joint

Bridge joint

Base joint

Welded rail joint

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Staggered or broken joint

Square or even joint

Compromise joint

Insulated joint

Expansion joint

17. Write short notes on rail section.

The rails on the track can be considered as the steel girders for the

purpose of carrying axle loads. They are made of high carbon steel to

withstand wear and tear. Flat footed rails are mostly used in railway track.

18. What are the functions of rails?

Rails provide a hard, smooth and unchanging surface for passage of

heavy moving loads with a minimum friction between the steel rails

and steel wheels

Rails bear the stresses developed due to heavy vertical loads, lateral

and braking forces and thermal stresses

The rail material used is such that it gives minimum wear to avoid

replacement charges and failures of rails due to wear

Rails transmit the loads to sleepers and consequently reduce pressure

on ballast and formation below

19. What are the requirements of rails?

They should be of proper composition of steel as given above and

should be manufactured by open hearth or duplex process

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The vertical stiffness should be high enough to transmit the load to

several sleepers underneath. The height of rail should, therefore, be

adequate

Rails should be capable of withstanding lateral forces. Large width of

head and foot endows the rails with high lateral stiffness

The head must be sufficiently deep to allow for an adequate margin of

vertical wear. The wearing surface should be hard

Web of rails should be sufficiently thick to bear the load coming on it

and should provide adequate flexural rigidity in horizontal plane

Foot should be wide enough so that rails are stable against

overturning, especially on curves

20. What is meant by hogged rails?

Due to battering action of wheels over the end of the rails, the rails get

bent down and get deflected at the ends. These rails are called hogged rails.

21. What is meant by corrugated or roaring rails?

In some locations, heads of the rails are found to be corrugated.

Vehicles passing over such rails produce a roaring sound. Such rails are,

therefore, called roaring rails.

22. What are the different forms of rail failure?

Crushed heads

Square or angular break

Split heads

Split web

Horizontal fissures

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Transverse fissures

Flowing metal in heads

Horizontal cracks

23. What is meant by wear of rails?

Due to movement of very heavy loads at high speeds, the concentrated

stresses often exceed the elastic limit of metal, resulting in the metal flow.

This flowed material of rails is chipped off by the striking of wheels. The

rail is then called worn out and this happening is called wear of rails.

24. What are the types of fittings and fastenings available in railway?

Fish plates

Spikes

Bolts

Chairs

Blocks

Keys

Plates

25. What do you understand by the term “Fish Plates” and what are its

uses?

Fish plates are used in rail joints to maintain the continuity of the rails

and to allow for any expansion or contraction of the rail caused by

temperature variations. They maintain the correct alignment of the line both

horizontally and vertically.

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26. What is meant by spikes?

Spikes are used for fixing rails to the wooden sleepers. There are

various types of spikes commonly used for holding flat footed rails. These

can be used with or without bearing plates below the rails.

27. What are the uses of spikes?

For holding the rails to the wooden sleepers

Spikes should be strong enough to hold the rail in position

Spike should be as deep as possible, easy in fixing, removal, cheap in

cost.

28. What is meant by chairs?

C.I chairs are used to hold the bull headed and double headed rails.

These chairs are fixed to sleepers by round spikes.

29. What is meant be blocks?

To provide the required gap between the two rails, steel pieces called

blocks or heel blocks are used. Such blocks are used between main rails and

check or guard rails.

30. What is meant by bearing plates?

Bearing plates are rectangular plates of mild steel or cast iron and are

used below flat footed rails to distribute the load on a larger area of timber

sleepers particularly of soften variety.

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31. What are the uses of keys?

Keys are tapered pieces of timber or steel to fix the rails to the chairs

on metal sleepers.

32. Define elastic fastening.

These are the special types of fastenings used for holding rails to the

sleepers firmly at a constant pressure without affecting the track structure for

sufficient time. These fastenings are suitable for high speed tracks as they

can withstand high frequency vibrations and shocks.

33. Define “Track modulus”.

Track modulus (µ) is an index for stiffness of track (i.e. resistance to

deformation) and is defined as load per unit length of the rail required to

produce a unit depression in the track.

34. List down the various causes of “Track stresses”.

The wheel loads

The dynamic effect of wheel loads

The hammer blow – due to overbalance of driving wheels of

locomotive

The horizontal thrust

The horizontal thrust – due to nosing action of the locomotive

Pressure exerted by flanges of wheels on sides of the rail

Stresses due to irregularities in the track

Additional stresses on curves

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UNIT – 3

1. Enumerate the necessities of “Curves”.

To bypass the natural or artificial obstacles

To provide easier gradients by diversions from the straight route

To route the line through areas having traffic potentialities

To balance the earth work in excavation and cutting thereby

minimizing the cost of construction

2. Write the types of horizontal curves.

Simple curve

Compound curve

Reverse curve

Transition curve

3. Define Simple curves.

The horizontal curve which consists of a single arc of a circle is called

a simple curve or simple Circular curve. Simple circular curves are

designated either by their degree of radius. They are inserted between two

straights or between two transition curves.

4. Define Compound curves.

The horizontal curve which consists of two or more arcs of different

circles with different radii, having different centers on the same side of the

common tangent and bending in the same Direction, is called a compound

curve.

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5. Define Reverse curves.

The horizontal curve, which consists of two arcs of different circles of

same or different radii, bending in opposite directions with a common

tangent at the junction, is called a reverse curve.

6. What is transition curve? Where is it provided?

Transition curve is defined as a curve of parabolic nature which is

introduced between a straight and a circular curve or between two branches

of a compound curve. Its radius rises from infinity to a selected minimum in

order to attain full super elevation and curvature gradually. This is also

known as spiral or easement curve. The transition curves are, therefore,

necessary to provide an easy change from a tangent to the radius selected for

a particular curve.

7. Define valley or sag curve.

Valley or sag curves are formed when a descending gradient meets

with an ascending gradient. When a train passes over sag, front portions of

the train ascend while rear portion may traverse on the descending gradient.

This compresses the couplings and buffers. Once the train passes on the sag,

again the couplings and buffers are under tension causing a jerk. In order to

avoid inconvenience, sag curves are introduced at the meeting points.

8. Define summit curve.

Summit curves are formed when an ascending gradient meets a

descending gradient. Deviation angle between two intersecting gradients is

equal to algebraic difference between them. When a trains climbs at a

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uniform speed and passes over them summit of a curve, acceleration begins

to act up on it and makes the train to move faster.

9. What is cant deficiency?

Cant deficiency occurs when a train travels on a curve at a speed

higher than equilibrium speed. It is the difference between theoretical cant

required for such higher speed and actual cant provided.

10. Define cant excess.

Cant excess occurs when a train travels on a curve at a speed lower

than equilibrium speed. It is the difference between actual cant and

theoretical cant required for such a lower speed.

11. List few objectives of signaling.

To provide facilities for the efficient movement of trains.

To ensure safety between two or more trains which cross or approach

each other’s path

To provide facilities for the maximum utility of the track.

To provide facilities for safe and efficient shunting operations

To guide the trains movement during maintenance and the repairs of

the track.

To safeguard the trains at converging junctions and give directional

indications at diverging junctions.

12. What are the types of signals based on the various categories?

Operating characteristics

Detonating signal (also called fog or audible signal)

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Hand signal (visual indication signal)

Fixed signal (visual indication signal)

Functional characteristics

Stop or semaphore type signal

Warner signal

Shunting signal (disc or ground signal)

Coloured – light signal

Locational characteristics

Reception signal

o Quoter signal

o Home signal

Departure signal

o Starter

o Advance starter

Special characteristics

Repeater or co – acting signal

Routing signal

Calling on signal

Point indicators

Modified lower quadrant semaphore signal

Miscellaneous signal

13. Write the types of transition curves and draw it.

Spiral curve

Cubic parabola

Bernoulli’s lemniscate

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14. Define shift and write its formulae.

For the main circular curve to fit in the transition curve, which is laid

in the shape of a cubic parabola, it is required be moved inward by a

measure known as the shift. The value of shift can be calculated using the

formula is given by,

𝑆 = 𝐿2

24 𝑅

15. What are the requirements of a transition curve?

It should be perfectly tangential to the straight

The length of the transition curve should be such that curvature may

increase at the same rate as the super elevation. This is necessary to

attain the full super elevation at the junction of transition and circular

curve.

This curve should join the circular arc tangentially (i.e.) curvature of

transition curve should conform to that of circular curve.

16. What is meant by Widening of gauge on Curves?

Due to impounding action of the wheels on curves, the gauge of the

track gets widened and the Rails get tilted outward. To prevent the tendency

of tilting the rail outward the gauge of the track on curves is suitably

widened. The amount of widening of gauge depends on the radius of the

Curve, gauge and rigid wheel base of the vehicles.

17. Write the formulae for widening of gauges.

𝑑 = 13 ( 𝐵 + 𝐿 )2

𝑅

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Where,

B = rigid wheel base in metres

For B.G track, B = 6m

For M.G track, B = 4.88m

R = radius of the curve in metres

L = lap of flange in metres

𝑑 = 0.02 √ℎ2 + 𝐷. ℎ Metres

Where,

h = depth of wheel flange below rail top level in cm

D = diameter of wheel in cm.

18. Define switch angle.

This is the angle formed between the running faces (gauge face) of

stock rail and tongue rail.

19. Define Angle of deflection.

The angle through which forward tangent deflected is called angle of

deflection of the curve. It May be either to the left or to the right.

20. What is meant by flange way clearance?

This is the distance between the adjacent faces of the stock rails or

running rails and the check or guard rails. It is provided for free movement

of the wheel flanges.

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21. What is flange way depth?

It is the vertical distance between the top surface to the running rails

or stock rails top to the surface of the heel block which is used between

stock rail and the check rail.

22. Define gradient.

Any departure of the track from the level is known as grade or

gradient, an up or rising gradient is one when the track rises in the direction

of movement, and a down or falling gradient is one when the track fails in

the direction of movement.

23. What are the Various Types of Gradients?

Ruling gradient

Momentum gradient

Pusher or helper gradient

Gradients at station yards

24. What do you understand by the term “Grade compensation”?

In order to avoid resistances beyond the allowable limits, the gradients

are reduced on curves and this reduction in gradients is known as grade

compensation for curves.

25. Define cant or super elevation.

When a vehicle negotiates a curve, it is subjected to a constant radial

acceleration which produces Centrifugal force acting horizontally at the

center of gravity of the vehicle, radially away from the center of the curve.

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To counteract the effect of centrifugal force, the level of the outer rail is

raised above the inner rail by a certain amount to introduce the centripetal

force. This raised elevation of outer rail above the inner rail at a horizontal

curve is called super elevation.

26. Differentiate between equilibrium cant and negative cant.

When the lateral forces and wheel loads are almost equal, the cant is

said to be in equilibrium. This equilibrium cant is provided on the basis of

average speed of the trains.

Elevation of outer rail below inner rail of turnout or branch track at

the place it meets main track on a curve is known as negative super

elevation/cant.

27. Define crossing.

A crossing is a device, inserted at a location, where two rails cross

each other. Purpose of the introduction is to enable the wheel flanges of rail

vehicles to pass from one track to another. Flanged wheels jump over the

gap provided from the throat to the nose of a crossing. Checkrails guide

wheels on the other side of the train vehicles in order to ensure that wheels

negotiate the gap properly and do not strike the nose.

28. What you mean by Diamond crossing?

When straight tracks or curved tracks of the same or different gauges

cross each other at an angle less than 90 degree, a diamond shape is formed.

So this crossing is called as diamond crossing.

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29. What are the various types of crossings?

On the basis of shape of crossing

Acute angle crossing or “V” crossing or frog

Obtuse angle crossing or diamond crossing

Square crossing

On the basis of assembly of crossing

Spring or movable wing crossing

Ramped crossing

30. What are the component parts of crossing?

A crossing or Vee piece

Point and splice rails

Wing rails

Check rails

Chairs at crossing, at toe and at heel

Blocks at throat, at nose, at heel and distance block

In some cases, packing below the wing rails at toe and throat

31. List down the characteristics of Crossing.

The assembly of crossing has to be rigid to stand against severe

vibrations

The wear on parts of wing rails opposite the nose and also of nose

itself must be protected

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32. What is meant by crossing number?

The number of crossing is defined as the ratio of spread (i.e. distance

between the point and splice rails at the leg of crossing, generally 30cm) to

the length of crossings are designated by this number and is denoted by the

symbol ‘N’.

33. What is meant by nosing action?

The wheels of the locomotive, wagons and compartments follow a zig

– zag path moving from one rail to another within the limits of wheel gauge

tolerance. This happening is called as nosing action.

34. List out the special types of signals.

Repeater or co-acting signals

Routing signals

Calling on signals

Point indicators

Modified lower quadrant semaphore signal

Miscellaneous signals

35. What is meant by turnouts and write its functions?

Turnout is the simplest combination of points and crossings which

enables one track either a branch line or a siding, to take off from another

track. So the object of turnout is to provide facilities for safe movement of

trains in either direction on both the tracks.

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36. Define tongue rail.

It is a tapered movable rail, made of high-carbon or -manganese steel

to withstand wear. At its thicker end, it is attached to a running rail. A

tongue rail is also called a switch rail.

37. What is termed as points and crossing?

Points and crossings are arrangements by which different routes are

connected. The connection facilitates movement of trains from one route to

another safely. It is also useful for marshalling and shunting operations in

station yards. Combination of points and crossings are termed as turnouts.

38. What is the necessity of points and crossings?

Points and Crossings provide flexibility of movement by connecting

one line to another.

They help in Imposing restrictions over turn outs which necessarily

retard the movements.

In regard of safety aspects, points and crossings are weak kinks or

points in the track which are susceptible to derailments.

39. List down the different types of track junctions.

Turnouts

Symmetrical split (or equivalent turnout)

Three throw switch (contrary and similar flextures)

Double turnout or tandem

Diamond crossing

Cross over’s (between parallel tracks and diverging tracks)

Single slip and double slip

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Gauntlet track and fixed point system

Scissor cross – over

Gathering lines or ladder tracks

Temporary diversion

Triangle

Double junctions

40. Define cross-over in track junction?

When two adjacent parallel or diverging tracks, which may be straight

or curved, are connected by two sets of turnouts, with or without a straight

length between them, the connecting line is known as cross-over.

41. Define Ladder tracks?

When a number of parallel tracks are branched off from the straight

track in Continuation of a turnout, it is called a gathering line or ladder track.

42. What is meant by flare?

It is the gradual or tapered widening to the flange way which is

formed by bending and splaying the end of check rail or wing rail away from

the gauge line.

43. Define buffer stop.

The dead end of a railway line is provided with a barrier erected

across the track to prevent the vehicles running off the track is called buffer

stop.

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44. Define switch.

A switch consists of a stock rail and a tongue rail. Switches are

tapered rails with the thicker end known as the heels, fixed to the main track

while thinner end known as the toe is kept movable.

45. What are the two types of switches?

Stub switch

Split switch

Loose heel type or articulated type

Fixed heel type or spring type or flexible type

Under cut switches

Overriding switches

Straight cut switches

46. What is meant by throw of switch?

It is the distance through which the toe of the tongue rail rotates

sideways, with heel of tongue rail as the centre of rotation.

47. Define Platform.

A raised level surface from where passengers board and alight from

trains at the station is called platform.

48. Write short notes on Drainage of Platforms.

All end platforms shall normally be sloped away from the track.

All drains from platform shelters, tea stalls toilets, water taps or other

sullage generation points shall be in pipes and normally discharge on

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the non-track slide of the end platform. If necessary longitudinal

covered drains may be provided on the platform.

49. What are the various sources of moisture in a railway track?

Surface water due to rain, dew or snow.

Hydroscopic water or Held water.

Seepage water

Moisture by capillary action In sub grade

50. What is meant by mechanical tamping or mechanized maintenance?

This is a mechanized method of maintaining the track by use of Tie

Tamping Machines. This method is more effective, economical and

efficient for maintaining high speed and super high speed tracks. This

method is widely used on Indian railways these days.

51. What is directed track maintenance?

Directed track maintenance is a method of track maintenance. This is

based on the directions that are given for maintenance given every day rather

than the routine maintenance. It is need based maintenance.

52. What is calendar system of maintenance?

Calendar system of maintenance is conventional method. Track

maintenance work to be performed by gangs on the course of a year.

53. Write any two necessity of Track Maintenance.

The strength of track structure goes on deteriorating or reducing due

to movement of high speed trains, heavy axle loads and repetition of

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loads. The elastic structure of railway track thus get disturbed in

alignment, gauge and surface level of rails.

The track structure is also subjected to other deteriorating effects like

rain water, action of sun and wind. The wear and tear of rails and of

rolling stock is then bound to take place due to their adverse effects.

The track structure has to bear too many other effects due to

curvature, speed and load, particularly on curves, points and

crossings, bridge approaches and at level – crossings.

54. Write the essentials of Good Track Maintenance.

The correct gauge is within specified limits.

Longitudinal levels are uniform.

The cross levels are same except on curves where difference in cross

levels is equal to the desired super-elevation.

Along straights, the alignment is perfectly linear.

There is a sufficient quantity of ballast bed.

The sleepers are well packed.

The formation is well maintained with good track drainage for

disposal of rain water.

55. Write any two advantages of Proper Track Maintenance.

A well maintained track provides safe and comfortable journey to

passengers. If the track is not maintained properly, there will e

discomfort to the passengers and sometimes, there may be a

derailment of vehicles, causing accidents and consequently loss of

lives and property.

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Proper maintenance of track increases the life of track as well as that

of the Rolling stock.

56. What is Rolling stock?

Rolling stock consists of locomotives, passenger coaches and goods

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

57. What are the advantages of good maintenance of railway track?

The life of both track as well as of rolling stock increases by proper

maintenance

A well maintained track imparts smooth riding quality surface for

vehicles which results in comfort to passengers and safety to goods.

There is also saving in operating costs as fuel consumptions is less by

locomotives due to reduced friction between wheels and rail surface.

Safety to passengers and goods encourages the use of railways and

better earnings.

58. What are the requirements of a track drainage system?

The track alignment should be made to rest on pervious naturally

drained soils.

The highest level of water table should be much below the level of

sub grade.

Sub surface water should be efficiently drained off by the sub surface

drainage system.

The surface water from adjoining Land could be prevented from

entering the track formation.

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59. List the methods of sub-surface drainage methods adopted in railways.

Drainage of capillary water

Drainage of seepage water

60. Define railway station.

Railway stations are selected locations along railway tracks where

trains stop for boarding and alighting of passengers, loading and unloading

of goods, detachment or attachment of wagons and compartments, crossing

of trains and for fuelling or watering of locomotives.

61. What are the data’s to be collected for the site selection of railway

station?

Acquisition of land

Proximity to town or village

Nature of land area

Approach roads to station site

Station site alignment

Site drainage

Station amenities

Type of station and yard

Role of authorities

62. What are the requirements of a railway station?

Public requirements

Traffic staff and police requirements

Train requirements

Requirements of locomotives

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Requirements for development of railways

63. What are the different classifications of railway stations?

Classification based on operational characteristics

Halt station

Flag station

Crossing station

Junctions

Terminals

Classification based on minimum signal requirement

‘A’ class station

‘B’ class station

‘C’ class station

‘D’ class station or Non – block stations

64. What do you mean by halt station?

This is the lower most in the hierarchy. In its simplest form, the halt

stations have rail level platform with name boards at either ends. Sometimes

a small waiting shed, which may also serve as booking office is also

provided.

65. What do you mean by flag station?

A flag station stands next to halting station, in ranking. The flag

station has a waiting hall, booking office, platforms with benches and

drinking water facilities. Importantly, the flag stations may have a control

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phone connected to one of the stations on either side for easy

communication.

66. What do you mean by crossing station?

The crossing stations have in addition to basic facilities, arrangements

and equipments to control movement of trains. This facilitates trains going

in opposite direction. In case of double line section, there are separate up

and down lines. This enables trains from either direction to pass

independently.

67. What do you mean by double line station?

Layout of a double line station, with separate up and down line is

different to certain extent.

68. What do you mean by junction station?

Railway stations, where two or more lines from different directions

meet are termed as railway junctions. The meeting may be between main

lines and branch lines or between main lines. Different lines are linked by

foot over bridges or other arrangements.

69. What do you mean by terminal station?

A station at which, a railway line or one of its branches terminates is

known as terminal station. Such terminal facilities require higher order

facilities such as servicing, repairing, reversing, sidings, changing of

carriages and such other allied facilities.

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70. What do you understand by the term Stations yards?

A yard is defined as a system of tracks laid usually on a level within

defined limits, for receiving, storing, sorting, making up new trains, dispatch

of vehicles and for other purposes over which movements are not authorized

by a time table. The various movements on a system of tracks are governed

by prescribed rules, regulations and signals.

71. Write the types of yards.

Coaching or Passenger bogie yard

Goods yard

Marshalling yard

Flat yard

Gravitational yard

Hump yard

Locomotive yard

72. Define marshalling yard.

A goods yard which deals with the sorting of goods wagons to form

new goods trains is called a marshalling yard.

73. What are the functions of marshalling yards and explain any one.

Reception

Sorting

Departure

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74. Define coaching or passenger bogie yard.

The main function of a coaching yard is to deal with the reception and

dispatch of passenger trains. Depending upon the volume of traffic, this yard

provides facilities such as watering and fuelling of engines, washing of

rakes, examination of coaches, charging of batteries, and trans-shipment of

passengers.

75. Define goods yard.

A goods yard provides facilities for the reception, stabling, loading,

unloading, and dispatch of goods wagons. Most goods yards deal with a full

train load of wagons. No sorting, marshalling, and reforming is done at

goods yards except in the case of ‘sick’ wagons or a few wagons booked for

that particular station. Separate goods sidings are provided with the

platforms for the loading and unloading of the goods being handled at that

station.

76. Define locomotive yard.

These yards provide services to locomotives and serve as stables. The

services include coaling, watering, repairing, oiling and cleaning. Normally,

junction stations have locomotive yards. Usually, they are constructed on

the same side as that of the marshalling yard. The loco yards have engine

sheds, inspection pits, repair pits and coaling site.

77. Define flat yard.

In this type of yard, the entire space of the yard is almost level and all

the sorting works or movements of wagons are carried out by means of

engines running to and from this arrangement is costly due to more

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consumption of power in the use of engines. But this type of yard is

justified where the available space is limited for the layout of marshalling

yards. The other two types of yards require more area for their layouts.

78. Define gravitational yard.

In this yard, the level of the natural ground is such that it is possible to

lay some tracks at a gradient. The tracks are so laid that the wagons move to

the siding assigned for the purpose of sorting by the action of gravity.

Sometimes, shunting is done with the help of gravity assisted by engine

power. However, it is very seldom that natural ground levels are so well

suited for gravitation yards.

79. Define hump yard.

In this type of yard, an artificial hump or summit is made through

proper earth work. Wagons are pushed upto summit or hump with the help

of engines. Then wagons move down the hump and go to sidings under the

action of gravity.

UNIT – 4

1. What are the classifications of airport?

Terminal airport

Defense

Commercial

o Ownership

Public

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Joint

Private venture

o Size

Smaller

Medium

Larger

o Area of operation

Domestic

International

ICAO classification

o Letter code : A , B, C, D, E

o Number code : 1, 2, 3, 4, 5

Intermediate landing port

2. What are the types of surveys conducted on airport?

Approach zone survey

Drainage survey

Meteorological survey

Natural resources survey

Soil survey

Topographical survey

Traffic survey

3. What is meant by clearway?

It is defined as a rectangular area at the end of a strip or channel in the

direction of takeoff over which the aircraft may make its initial climb.

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4. List out the merits and demerits of air transport.

MERITS:

Accessibility

Continuous journey

Demand for technical skill

Emergency use

Engineering use

Saving in time

DEMERITS:

Flight rules

Operating expenses

Safety

Weather conditions

5. What are the drawings should be prepared for construction of new

airport?

Drainage plan, grading plan, Lighting plan, Master plan, Obstruction

plan, paving plan and Topographic plan

6. What is the necessity of surveying in construction of new airport?

To ascertain the characteristics of soil.

To workout the detailed estimate of the project.

To prepare suitable drawings

To make provision for future extension of the airport

To give an idea of the meteorological conditions prevailing at the

proposed site

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7. What are the three aspects considered for the airport planning?

Adequate access to the metropolitan area

Securing sufficient airspace for access to the air

Sufficient land for carrying out ground operations

8. Write the objectives of airport planning.

Justify the need for an airport

Formulate a layout plan for the airport and design of runways,

taxiways and airport buildings

Prepare cost estimation

Propose institutional arrangement

9. What are the factors affecting the size of an airport?

Elevation of the airport site

Meteorological conditions

Performance characteristics of aircrafts

Volume of traffic

10. What are the environmental factors considered in the development of a

new airport or the expansion of an existing one?

Environmental Impact Assessment (EIA)

Environmental Impact Statement (EIS)

Environmental Management Plan (EMP)

11. Define Turning zone.

Area of airports used for turning operations of aircrafts is termed as

turning zones. In the event of any emergency like engine failure, if pilots

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opt for landing immediately after taking over, aircrafts have to come in line

with runways before landing. Normally, area of an airport other than an

approach zone is used for turning.

12. Comment on clear zone.

Clear zone is the innermost portion of an approach zone. It is the

most critical part of an approach zone from obstructions point of view. As

name itself indicates, the portion should be clear and no developments of

any type are permitted.

13. Define apron.

It indicates a defined area of the airport to accommodate aircrafts for

loading and Unloading of cargo and passengers, parking, refueling, etc. It is

usually paved and is located in front of the building or adjacent to hangers.

14. What are the three factors which affect the size of an apron?

Gate position

Number of gates

Systems of aircraft parking

15. Define gate position.

The space allotted to an aircraft parking at a loading apron is known

as gate position.

16. Define holding apron.

The portion of paved area which is provided adjacent to the ends of

runway in case of busy airports is known as the holding apron.

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17. Define orientation of the runway.

The orientation of a runway is defined by the direction, relative to

magnetic north, of the operations performed by aircraft on the runway.

Typically, but not always, runways are oriented in such a manner that they

may be used in either direction. It is less preferred to orient a runway in such

a way that operating in one direction is precluded, normally due to nearby

obstacles.

18. Define runway.

A defined rectangular area prepared for landing and take-off of

aircrafts and over which aircrafts runs on ground.

19. What are the four basic patterns of runway?

Single runway

Parallel runways

Intersecting runways

Divergent or open – V runways

20. Write the design elements of a runway.

Runway orientation

Length of runway – basic and corrected runway lengths

Runway width

Width and length of safety area

Transverse gradient

Longitudinal and effective gradient

Rate of change of longitudinal gradient

Sight distance

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Design of runway pavement

21. Write the elements of geometric design of runways.

Runway length

Runway width

Width and length of safety area

Transverse gradient

Longitudinal and effective gradient


Sight distance

22. What are the markings made on the runways?

Runway centre – line marking

Runway edge stripes

Runway numbering

Touchdown or landing zone

Threshold marking

Two or more parallel runways

23. What are the types of runway lightings?

Emergency lighting

Aeronautical beacons

Approach lighting system

Runway lead – in lighting systems

Runway threshold identification lights

Runway edge lights

Runway threshold and wing bar lights

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Runway end lights

Runway centre line lights

Runway touchdown zone lights

Stop way lights

24. What are the corrections required for runway length?

Correction for elevation

Correction for gradient

Correction for temperature

25. What do you understand by the term basic runway length?

The length of the runway based on the following assumed conditions

is known as the basic runway length.

No wind is blowing on the runway

The aircraft is loaded to its full loading capacity

The airport is situated at sea level

There is no wind blowing on the way to the destination

The runway is leveled in the longitudinal direction or in other words,

it has zero effective gradient

The standard temperature is maintained along the way

The standard temperature of 15oc exists at the airport

26. Define taxiway.

A defined path on a land aerodrome selected or paved for the use of

taxiing aircraft to and from the runway and loading apron is known as

taxiway.

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27. Mention the different types of aircraft propulsion.

According to the method of propulsion, the aircrafts can be classified

in the following three categories

Piston engine

Jet engine

Turbo jet

Turbo propulsion

Ram jet

Rocket engine

28. Differentiate between approach zone and approach surface.

APPROACH ZONE APPROACH SURFACE

An approach zone is an area

through which aircrafts approach or

leaves airports. It is the climb out

and landing path. In this zone,

aircrafts loose or gain altitude at a

very slow pace as compared to

forward speed. In view of this,

wider clearance on both sides of the

runways is required in the approach

zones of the airport.

A line rising at a particular slope

from the runway – end represents

the obstruction clearance line and

the imaginary inclined plane

containing this line and directly

above the approach area is known

as approach surface.

29. What is meant by wind rose diagram?

The diagram showing direction, duration and intensity of wind over a

certain period in a specified region is known as wind rose diagram.

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30. What are the parameters represented in a wind rose diagram?

Direction of wind

Duration of wind

Intensity of wind

31. Name the different characteristics of aircrafts?

Aircraft capacity

Aircraft speed

Aircraft weight and wheel arrangement

Fuel spilling

Jet blast

Minimum circling radius

Minimum turning radius

Noise

Range

Size of aircraft

Takeoff and landing distances

Type of propulsion

Tyre pressure and contact area

32. What are the data’s to be collected for airport site selection?

Regional plan

Types of airport

Ground accessibility

Topography

Soil characteristics

Meteorological factors

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Wind

Frost and fog

Temperature

Noise nuisance

On – site and off – site infrastructures

Shape and dimensions of site

Future development

Comprehensive evaluation

33. Define airport obstructions and zones.

Restrictions and removal of obstructions in airspace around airports

are essential to conduct safe aircraft operations. Obstructions may be

broadly divided into two categories. They are,

Imaginary surfaces

Objects with actual heights

The different types of zones are,

Approach zone

Clear zone

Turning zone

34. What is meant by zoning?

It pertains to the enactment of legislation for a restricted development

of the area surrounding the airport so that no structure protrudes above the

obstruction clearance line and thus cause hazard to safe air navigation,

especially in the approach and turning areas.

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35. What are the two types of zoning?

Height zoning

Land use zoning

36. What are the phases of Master plan by FAA recommendation?

Phase І: Airport Requirements

Phase ІІ: Site selection

Phase ІІІ: Airport plans

Phase ІV: Financial plans

37. What do you mean by airport capacity?

The number of aircraft movements which an airport can process or

handle within a specified period of time, usually an hour, is called the airport

capacity. A landing or take off operation is taken as one movement.

38. Define wind coverage.

The percentage of time in a year during which the cross wind

component remains within the limit of 25kmph is called the wind coverage

of the runway.

39. Define Hangar.

The large shed erected at the airport for the purpose of housing,

servicing, and repairing of aircrafts is known as hangar.

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40. Define terminal area.

The portion of the airport other than the landing area is known as

terminal area and it includes terminal building, aircraft apron, cargo storage

building, hangars, automobile parking area, etc.

41. Define terminal building.

The building or buildings which are meant for providing facilities to

all Passengers, for serving as office for airport management and for carrying

out other non- aeronautical functions are known as terminal buildings. They

act as the focal points of the terminal area.

42. What is the main function of hangar?

The main function of a hangar is to provide an enclosure for housing

and repairing of the aircraft. They are constructed of steel framework

covered with the galvanized iron sheets.

UNIT – 5

1. Specify the functions of taxiway.

The main function of taxiways is to provide access from the runways

to the terminal area and service hangars. It is evident that the speed of

aircraft on the taxiway will be much less than that on the runway at the time

of landing or take off. The standards for the taxiway design and

construction will therefore not be as rigorous as for the runway.

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2. Differentiate cross wind and head wind components.

CROSS WIND COMPONENT HEAD WIND COMPONENT

It is not possible to get the direction

of opposite wind parallel to the

centre – line of the runway length

everyday of throughout the year.

For some period of the year at least,

the wind may blow making some

angle θ with the direction of the

centre – line of the runway length.

If ‘V’ kmph is the velocity of the

inclined opposing wind, its

component 𝑉 sin 𝜃 which is normal

to the centre – line of the runway

length is called cross wind

component.

The runway is usually oriented in

the direction of the prevailing

winds. The head wind indicates the

wind from the opposite direction of

the head or nose of the aircraft

while it is landing or taking off.

3. What are the advantages of head wind?

During landing, it provides a breaking effect and the aircraft comes to

a stop in a short length of the runway

During takeoff, it provides greater lift on the wings of the aircraft

4. What are the elements of geometric design of taxiway?

Length of taxiway

Width of taxiway

Longitudinal gradient


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Sight distance

Transverse gradient

Turning radius

Width of safety area

5. What are the markings made on taxiways?

Taxiway centre line marking

Taxiway holding position marking

Taxiway intersection marking

6. What are the types of taxiway lightings?

Taxiway centre line lights

Taxiway centre line lights on rapid exist taxiways

Taxiway centre line lights on other exit taxiways

Taxiway guard lights

7. What are the factors should be consider for layout of taxiway?

Arrangement

Busy airports

Crossing

Higher turn – off speeds

Route

8. What are the factors considered for the location of exit taxiways?

Air traffic control

Exit speed

Location of runways

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Number of exists

Pilot variability

Topographical features

Types of aircraft

Weather conditions

9. Enumerate the necessity of aircraft classification.

The necessity of aircraft classification is the method of propulsion and

method of engine is provided. The main purpose of providing an engine to

the aircraft is to make available the force for propelling the aircraft through

the air.

10. Define “turning radius of taxiway”.

A horizontal curve is to be provided whenever there is a change in the

direction of the taxiway. It is necessary to design the curve in such a way

that the aircraft can negotiate it without significantly reducing the speed.

For this purpose, the circular curve of large radius is most suitable and its

radius can be obtained from the following formula

𝑅 = 𝑉2

125 𝑓

Where,

R = radius of curve in m

V = speed of aircraft in kmph

f = coefficient of friction between the tyre and pavement surface usually

assumed as 0.13

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11. Mention the purpose of installing visual aids at the airport?

To avoid accidents during landing of the aircraft

To convey to the pilot the ground to air visual information required

during landing

To direct the pilot to make the landing of the aircraft in the landing

area only

To enable the pilot to locate and identify the particular feature

specified by the marking

To grant safety to the persons and properties

To maintain an orderly flow of aircraft without any congestion

To satisfy the visual requirements for takeoff and taxiing

12. What are the airport markings?

Apron marking

Landing direction indicator

Runway marking

Shoulder marking

Taxiway marking

Wind direction indicator

13. What are the guidance and information required by the pilots during

landing operation?

Alignment guidance

Height information

Visual parameters

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14. What are the factors, which affect the type and intensity of airport

lighting?

Airport classification

Amount of traffic

Availability of power

Nature of aircraft using the airport

Type of night operations planned

Type of the landing surfaces provided

Weather conditions

15. Give the elements of airport lightings.

Airport beacon

Approach lighting

Apron and hangar lighting

Boundary lighting

Lighting of landing direction indicator

Lighting of wind direction indicator

Runway lighting

Taxiway lighting

Threshold lighting

16. Define heliport.

The area for landing and taking off of helicopter is known as heliport.

17. What are the two arrangements adopted for approach lighting?

Calvert system

ICAO system

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18. Define the term visibility.

The greatest distance, to which a prominent object of certain specified

dimension is perceivable to the eye, the object being observed in the day

light during day and properly lit during night under the existing atmospheric

conditions is known as visibility.

19. Define ceiling.

The meteorological visibility is also generally associated with the

height of the underside of a dense cloud above the airport surface. The

height is referred to as the ceiling.

20. What are the broad principles that are to be observed in the design of a

terminal building?

Arrival and departure areas

Baggage delivery

Information

Movement

21. What are the basic requirements to be kept in mind while deciding the

site for a terminal building?

It should be centrally located with respect to the runways

It should have convenient and easy access to the highway

It should have enough provision for future expansion

It should have favorable orientation with respect to wind,

topographical features of the area, etc.

There should be adequate space available for the parking of the

vehicles

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The site should have easy facility of natural drainage

The utilities like water, sewage and telephone should be easily

available

22. What is the importance of air traffic control?

It avoids the possibility of occurrence of the accidents in the air

It grants the economic and efficient utilization of the aircraft and the

airports

It guides the aircraft to their destinations safely and speedily

It increases the confidence of the passengers using the facility of air

travel

It separates the aircraft to a safe distance during their flight both

vertically as well as horizontally

23. What are the three components of an air traffic control network?

Control centres

Control towers

Flight service stations

24. What are the types of air traffic control aids?

En route aids or airway aids

Landing aids or terminal aids

25. Define passenger flow.

The design of the terminal building should be such that an

uninterrupted flow route is formed for the passengers to follow on or off an

aircraft without offending or disturbing each other.

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26. Define calm period.

The absence of appreciable wind, generally considered as 6kmph or

less is called the calm period. The knowledge of calm periods of a particular

place throughout the year plays an important role in designing an airport.

27. What are the systems of aircraft parking?

Frontal or linear system

Open – apron or transporter system

Pier or finger system

Satellite system

28. What are the different types of parking of aircraft?

Nose – in parking

Angled nose – in parking

Nose – out parking

Angled nose – out parking

Parallel parking

29. Define time of concentration.

The total time required by the flow to reach to the maximum limit is

known as the time of concentration and it consists of two parts are time of

entry and time of flow.

30. What are the functions of airport drainage?

To intercept and divert the surface and groundwater flow originating

from lands adjacent to the airport

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To lower the sub – surface water level in the airport so as to be within

permissible limit

To remove the surface runoff from the airport

31. What are the characteristics of airport drainage?

Absence of side surface ditches or drains

Combined drainage pipe for surface and sub – surface drainage

Comparatively flat longitudinal and transverse grades

Concentration of the outfall flow

Extensive area under consideration

Heavy concentrated wheel loads of the modern aircraft

Large percentage of paved areas in the form of the aprons, taxiways

and runways

Proper provision of future runway extension

Requirement of rapid drainage for the safety of the aircraft operations

Shallow water courses

Varying soil conditions

32. What are the basic requirements of airport drainage system?

Capacity

Future expansion

Rapid drainage

Strength

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33. What are the aims of Airport drainage?

If the sub – surface drainage system is improper, it may moisten and

weaken the sub – grade and thus, reduce its load bearing capacity,

resulting in the failure of pavements of runways, taxiways, etc.

If the surface drainage system is improper, it may result in the

ponding on the pavements of runways, taxiways and aprons which

might prove hazardous to the takeoff and landing operations of the

aircraft

It grants longevity to the pavements

It increases the efficiency of the airport

It is essential for proper and safe functioning of the aircraft

It reduces the maintenance cost of an airport

It shortens the periods during which the airport might have to be kept

out of use due to inundation, etc. The closing down of the airport

results in great loss in addition to the inconvenience of the passengers