Page | 285 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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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