TRANSPORT Flashcards
0.3 Suppose if you are associated with a
highway project, which drawings will
usually be prepared by you?
Key map, index map, preliminary survey plans,
detailed plan, detailed X-section land
acquisition plan etc.
0.2 What are the basic requirements of an ideal
alignment?
Ans. Short, easy, safe & economical.
Which concept is used in arriving at the
best road system out of the alternate
proposals?
Saturation system i.e. maximum utility per unit
length of road.
What is the thirtieth highest hourly volume?
It is the hourly volume that will be exceeded
only 29 times in a year, which is considered
economical for design.
The length of valley curve is based on the
which criteria?
Comfort condition, head light sight distance.
What are different traffic control devices?
Signs, signals, markings, islands etc.
What are the various measures to
decrease the accident rates?
Engineering measures, Enforcement
measures, Education measures (EEE).
What is the purpose of divisional island?
To divert the traffic into definite travel path at
the intersection.
When are rotary intersections provided?
When vehicle flow rate > 500 vehicle/hr but
<3000 vehicle/hr and at least 30 % traffic
turning right.
What is the cause for the initial concavity
of the load-penetration curve in CBR test?
(a) The top layer of the specimen being too
soft or irregular
(b) The bottom surface of the plunger or the
top surface of the soil specimen not being .
truly horizontal
What is the equivalent single wheel load?
The total stresses due to the dual wheels at
any depth greater than 2S is considered to be
equivalent to a single wheel load of
magnitude 2P.
where, S = spacing between the two tyres.
What is the difference between abrasion
and attrition?
Abrasion is due to moving traffic while attrition
is the mutual rubbing of stones/aggregates
What do you understand by the Mud
pumping in a typical rigid pavement?
Soil slurry ejects out through the joints.
What is the significance of tyre pressure
in the design of upper layer of pavement?
The tyre pressure of high magnitudes demand
high quality of materials in upper layers of
pavement.
If the stability of the local soil is not
adequate for supporting wheel loads, what
measures would you adopt?
The properties of the local soil can be
improved by the soil stabilization techniques
What is the frost heaving?
Frost heaving (or a frost heave) is an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary).
What is the Bituminous Bound Macadam?
It is premixed construction method consisting
of one or more courses of compacted crushed
aggregate premixed with bituminous binder,
laid immediately after mixing.
What are W B M roads? What is their
construction procedure?
These are water bound macadam roads. Following are the steps of their construction: (a) Preparation of foundation (b) Provision of lateral confinement (c) Spreading of coarse aggregate (d) Rolling (e) Application of screening (D Sprinkling and grouting (g) Application of binding material.
What do you understand by Grade
Compensation?
Amount of gradient is reduced, wherever a
curve and gradient has to be provided
together
How the pavement is evaluated and how
the strengthening of pavement is done?
Structural evalution by plate bearing test.
Equipment used is Benkelman Beam.
The surface condition of flexible pavement may
be evaluated by unevenness (Bump
Integrator), ruts, patches and cracks.
Rolling Stock?
Rolling Stock: It consists of all the vehicles
that can move on a railway line. Rolling stock
can be classified as powered and unpowered
rolling stock. Locomotives are powered rolling
stock while wagons, coaches etc. are
unpowered rolling stock
What do you understand by the relief of
stresses in rails?
The group of wheel loads, counteract the
bending moment developed by a single wheel
load.
What is the creep in rails & how to prevent
it?
Longitudinal movement of rails, prevented by
using steel sleepers, anticreepers I anchors
and pulling back the rails, etc.
What material as ballast you would suggest
for high speed tracks and why?
For high speed tracks, crushed rock is the
best material to be used as ballast. The ballast must be hard, durable and angular, free from
organic impurities and inorganic residues
What are the advantages and
disadvantages of tramc signals?
Traffic signals: At intersections where there
are large number of crossings, the crossing
streams of traffic flow are separated by time
segregation. Traffic signals are control devices
which alternatively direct the traffic to stop and
proceed.
Advantages:
(a) They provide orderly movement of traffic.
(b) They reduce certain type of collisions.
(c) Pedestrians can cross the roads safety.
(d) Automatic and properly co-ordinated/
syncrohised traffic signals are intact
economical as compared to manual
control.
�:·.Disa’dvantages ,,
(a) Rear-end collision chances increases.
(b) Improperly designed traffic signals may
lead to impact at intersections.
(c) Failure of signal leads to traffic
congestions.
What are the various types of stresses
induced in the railway track?
Types of stresses induced in railway track are:
(a) Residual stresses which result due to rail
manufacturing process.
(b) Thermal stresses result due to the
restraining of expansion or contraction of
rails due to variation in temperatures.
(c) Bending stresses which arise due to
moving of rolling stock. These get
magnified due to dynamic effect.
(d) Stresses due to unforeseen reasons.
(e) Contact stresses due to interaction of rail
and wheel at the contact surface.
What are the different types of bituminous
materials used in road constructions?
(ESE 2016)
Different types of bitumioous materials:
Bitumen material used in road construction
can be classified as:
(a) Bitumen:
(i} Petroleum asphalt
(ii) Natural asphalt
(b) Tar: Obtained when natural organic
materials like coal and wood are carbonized/
distilled destructively in the absence of air.
What are the various tests for judging the
suitability of road stones
Tests for suitability of road stones: The following tests are carried out: (a) Crushing test (b) Abrasion test (c) Impact test (d) Water absorption test (e) soundness test
What are the various tests carried out on
bitumen?
Tests carried out on bitumenf: The various
tests carried out on bitumen are:
(a) Penetration test
(b) Ductility test
(c) Flash and fire point test
{d) Softenoing point test
(e) Test for water content
(f) Loss on heating test
(g) Specific gravity test
(h) Viscosity test
(i) Spot test
U) Solubility testDiscuss •• the desirablel properties. £1
bitumen.
Desirable properties of bitumen: The desirable properties of bitumen are: (a) Adequate viscosity at the time of mixing and compaction. (b) It should not be too much susceptible to temperature. (c) It should not loose adhesion with aggregates in presence of water.
Explain ‘Flexible and Rigid’ pavements.
Flexible pavements: In flexible pavements,
the load transfer occurs through grain to grain
and these pavements . do not PQS�ess flex�r?l
strength.
IRC 37
Rigid pavements: In rigid pavements, load
transfer occurs through flexural strength of
pavement.
IRC 58
What-are the desirable. pro perties· of
_b_ituminous mixes? What-are the step�in bituminous mix design? Discuss brie.fly
Desirable properties of bituminous mixes:
Following are the desirable properties of
bituminous mixes:
(a) Stability: Resistance of paving mix
against deformation under loads.
(b) Durability: Resistance of the mix against
weathering and abrasive actions.
(c) Flexibility.
(d) Skid resistance.
Steps followed in �ituf!1inous mix design:
(a) Selection of aggregates which possess
sufficient strength, hardness, soundness,
toughness etc.
(b) Selection of aggregate grading: Densely
graded aggregates are preferred.
(c) Specific gravity determination
(d) Proportioning of aggregates
(e) Specimen preparation
(f) DeterminatOon of specific gravity of
compacted specimen.
(g) Solubility tests on compact�d specimens.
(h) Selection of optimum bitumen content.
What do you unders.tand,by crazing?
Bre a k’ 1ng up of road surface layer through
crack’ · lng Into regularly shaped areas is known
as crazing.
What is a dynamometer car and why ‘Is �t
used?’
Dynamometer Car: It is a railroad maintenance
way car for measuring various characteristics
of a locomotive like tractive effort, power, top
speed, drawbar pull, brake pipe pressure etc.
It was first used in Britain
Discuss the necessity and effects of coning
of wheels and tiling of rails.
Conning of wheels: Coning of wheels is a
method of beveling the wheels to avoid
depreciation to the wheels and rims. In
general, the wheels are conned by a cone of
semi-angle. It is based on the theorem of coning
Rail wheels are usually beveled by means of
a ·cone semi:.angle onne arrangemeril on n ·
20. The rails-are also:fixed at thi_s - identical .·,
angle (1 in·20) to the perpendicular
What do you understand by a railway track
and a permanent way? Mention the
requirements of an ideal permanent way.
Permanent way: The permanent way is the
element of railway lines which generally
include the pairs of rails laid on the sleepers
which in turn are embedded in ballast,
intended to carry the rail traffic. It is described
as permanent way because in the earlier days
of railway construction, contractors often laid
a temporary track to transport soil and
materials at the site; when this work was
substantially completed, the temporary track
was taken up and the permanent way
installed.
Railway track is a major part of permanent
way and it actually carries the train load. It is
ge.[1erally uble headed_fixed to the sleepers
at the bottom head and is made of steel.
What are the objects of signaQiing?
Describe the engineering principles of
signalling
Signalling: At intersections where there is a
possibility of right turn and straight movement
of traffic, there the possibility of accidents
are very high. However due to massive
expansion of cities and consequently in the
number of intersections and vehicles, it is not
possible to deploy a traffic police personnel
at every intersection. Thus different streams
of traffic are segregated by time segregation.
Traffic signals are control devices which
alternatively direct the traffic to stop and
proceed at intersections by the use of
GREEN, AMBER/YELLOW, RED signals.
Principles of signalling:
(a) STOP or RED phase of the signal R1 is
the sum of GO and CLEARANCE intervals
i.e. sum of green and amber signals for
cross traffic i.e. G2 + A2.
(b) Towards the end of RED phase, there may
be a short duration when the AMBER lights
are put on along with RED signal to imply
‘get set go’.
(c) CLEARANCE amber phase is provided
just after the GREEN phase and before
the RED phase in order to provide
stopping time for the coming vehicles to
stop at stop line.
(d) GREEN time is decided on the basis of
traffic volume during peak hour and to
enable the queued vehicles to clear otf
the signal in one cycle.
Explain the necessity of sleeper in railway.
What are the d esirable qualities or
requirements of good sleepers?
Railway sleepers transfer the load of train to
the ballast underneath. Also they hold the rails
in position and at proper alignment.
Requirements of a good sleeper:
(a) It should be economical.
(b) It should have minimum possible initial
and maintenance costs.
(c) The fittings should be such that they
can be easily adjusted.
(d) Weight should not be too heavy or too
light.
(e) It should not be easily damaged by antinationals.
(f) They should ,be caP._�ble of resisting
shock� ano vib.[ tions.
(g) The :.nsulation of ails should be possible
for track circuiting, if required through
sleepers.
(h) It should be so designed that it could
not be disturbed from its position easily
by the passage of trains
·steam traction is _being gradually replaced
by diesel and electric tractions on world
railways”. Why?
Steam traction is being replaced by diesel
and electric traction since steam traction
requires burning of coals which causes
pollution in the air. Also the horse power that
can be achieved by diesel and electric traction
is much higher than that of steam traction.
Under–what .. circumstances and why the
electric traction is being adopted in place
of steam and diesel tractions?
Electric traction possesses the advantage
of being pollution free as compared to steam
or diesel traction. Also it is easier to design
electric locomotives with much higher horse
power than that of steam or diesel
locomotives.
Explain. spot speed, run.rning speed, spacemean speed Ume-mean speed and average speed. How are spot speed studies carried out? . . . (ESE 2016)
Spot speed: It is the instantaneous speed of
a vehicle at a particular:. point or secti�n of a road.
Running Speed: It is the average speed
maintained by a vehicle over a particular
stretch of road, while the vehicle is in mot_ion . ..
It is obtai ned by dividi ng the distance “
travelled by the time for which the vehicle was
actually in �otion.
Space mean speed: It is the average speed
of vehicles over a particular length of road at
any given time. :t
Time mean s peed: It is the s peed
distribution of vehicles at a particular point :
on the road and is the average -of
instantaneous speeds of the_
�ehicles at _
a
spot.
Average speed: It is the average of spot
speeds of all the vehicles passing over a
given point on the road.
There are a number of methods to measure
the spot speeds of vehicles. It can be obtained
by finding the running speed of vehic�es over
a short distance, say 50 m or 100 m. It can
also be o btained by measuring the
instantaneous speeds of the vehicles crossing
a particular section of road.
Explain brieHy the various aspects
investigated during parking studies. What
are the uses of these studies?
Parking studies: It is carried out to assess
the demand by the vehicle users for parking
space that is required to park their vehicles.
(a) Parki ng demand wh ich can be
determined by various methods.
(b) Parking characteristics to assess the
present parking practices I
characteristics in an area.
(c) Inventory of parking space in the form
of a map which shows all the available
kerb parking and off-street parking
places
Explain traffic capacity, basic capacity,
possible capacity and practical capacity
Traffic capacity: It is the ability of a roadway
to accommodate a traffic volume. It is the
maximum number of vehicles in a lane that
can pass a given point per unit time.
Basic capacity: It is the maximum number
of passer.ger cars that can pass a given poi.nt
on a road in one hour under the most ideal
road and traffic conditions. It is the theoretical
capacity of a road.
Possible capacity: It is the maximum number
of passenger cars that can pass a given point
on a road in one hour under the prevailing/
existing road and traffic conditions. It is
generally much lower than the basic capacity.
Practical capacity: It is the maximum
_,., _ · :
-
number of passenger cars that can pass a . given poin{on”
a �o�d in one hour without traffic
· . qensity, being. so great so as to cause
,
-;
unreasonable delay and other hazards/
restrictions to driver’s maneuverability under
the prevailing/existi ng road and traffic
conditions.
What are the various types of traffic
markings commonly used? What are the
uses of each?
(a) Pavement markings: These..are generally
of·.white colour: Yellow colour marl
What are the various causes of traffic
accidents? Discuss the m ethod of
analyzing the speed of vehicle involved in
the accident.
Causes of traffic accidents: The four basic elements of traffic accidents are: (a) Road user (b) Vehicles (c) Condition of the road (d) Environmental factors, traffic etc. The various causes of accidents are: (a) Drivers driving the vehicles carelessly violating the traffic rules. (b) Pedestrians violating the use of carriage way/road which is meant for vehicular traffic. (c) Passengers boarding and de-boarding the vehicles. (d) Defects in the vehicles like brake failure, tyre bursts etc. (e) Road conditions (f) Road geometric design like improper sight distance, inadequate curve design etc. (g) Weather which includes fog, snow, du�t. mist etc. (h) Animals straying on roads.
What is a traffic rotary? What are its
advantages and limitations, in particular
reference to traffic conditions in India?
(ESE 2016}
Traffic Rotary is a road intersection which is
made enlarged where all converging vehicles
move in a one direction around a large island
before they get separated out from the rotating
traffic. It is used to eliminate the necessity of
bringing the vehicle to a halt at signals. Also
the crossing of vehicles get eliminated thereby
reducing the conflict points.
Advantages of a rotary:
(a) The crossing movement of vehicle is
converted to weaving movement and
also the vehicles need not to stop.
(b) All traffic including turning right and
going straight have equal opportunity as
those turning left.
(c) Although the distance to be travelled in
. ‘II a rotary is large compared to s1gnals stt
the overall fuel consumption is less in a
rotary. .
(d) Rotary eliminates the necessity of trafftc
pollee and traffic control staff and also
there is no possibility of signal failure
etc.
(e) The possible number of accidents in a
rotary is less than that of signalized
intersections.
(f) Rotary possess the highest capacity
among all other intersections at grade.
Limitations of a rotary:
(a) Rotary requires a comparatively large
area and thus cannot be used where
space limitation is there.
(b) When pedestrian traffic is large then
rotary itself cannot control the traffic and
a traffic police personnel· has to be
deployed. _
(c) Mixed traffic involving a-large-number�
of cycle use[s makes the rotary operation .
quite complex.
(d) When more than seven roads�are
intersecting or tl}e angle g,f ntersection
of two roads is too acute then rotary.:
operation is compleX. -·
(e) Rotary is not economically feasible where
the traffic volume is too low
Explain grade separated intersections, their
advantages and limitations.
Grade separated i.ntersec�ions: This type
of intersection causes the least oolay and is
also safe for cross moving traffic. The
separation of grades is achieved by means
of a bridge or an under-pass thus eliminating
the cross moving traffic conflict. Ramps are
provided to transform the grade separation.
Advantages of grade separation:
(a) Maximum ease is given to the cross
moving traffic at grade separation.
(b) It avoi·ds the necessity of bringing the
vehicle to a halt.
(c) It increases the overall comfort and
convenience to the vehicle users.
(d) It is an essential part of controlled access
roads like expressways anod freeways.
(e) It is possible to provide grade separation
for all angles of intersection at grade
roads
Disadvantages of grade separation:
(a) It is costly to provide grade separation.
(b) It is difficult where there is a limited right
of way particularly in metro cities.
(c) Its constr�uction disturbs the existing
traffic for a considerable period of time
What’ typ otf ings �are: used :-to· fix ul.
headed raiHron wooaen sleeper?
Round spikes, dog spikes, stewart keys, etc.
0.55 Why is it important for a highway engineer
to study the behaviour of soil?
For a highway engineer it is important to
study the behavior of soil. All roads and
other traffic elements are founded on ground
which requires the study of soil
characteristics. Soil study is required to avoid
the possible failure of traffic structure due to
frost, heave, expansion, liquefaction, piping,
scourin·g etc. Quality and characteristics of
soil determines the type of foundation to be
provided for a traffic facility.
If we consi8er’the creep ofrails, which’tYpe
of sleep’er –aoes not’·need anchoring
· arrangement?”-
Concrete sleeper
In-which- type of the track wear of the rail
is ma>cimum
Sharp curve
.,-
Metal sleepers� are,. sup·erior· than ·the
‘
wooden sle.epers;why
They are more durable.
If we consi8er’the creep ofrails, which’tYpe
of sleep’er –aoes not’·need anchoring
· arrangement?”-
Concrete sleeper
Why·the signals are not-cprovided wnere
-the track- is provided ·with. momentum
gradient?
Otherwise train may stop and momentum is
brought down to zero.
How rail isJixed to steel sleepers?
By using keys between lugs or loose joints.
What. is taxiway�
It connects the runway to the apron
How can we reduce the wear ln·the·rall?
By decreasing the number of rail joints.
Which typ’Evot l is· installed as the
second signal on the main signal post for ‘.
better v�sibility?
Co-acting signal.
What do you understand by traversong
bridge?
Which can be rolled forward and backward.
Which type of signal is provided beyond
the trailing points and switches in a railway
yard?
Advance starter.
What Is the use of. base course In rigid
pavement?·
Prevention of pumping.
What is the advantage of e gg-shaped
tunnel?
It gives the self cleansing velocity even in dry
weather.
What is castor angle?
Angle between longitudinal axis of aircraft and
the direction of movement of the nose gear
What do you understand by the maximum
gross take-off weight of an aircraft?
The empty operating weight plus the payload
, What is’floating dock?
A chamber in which a ship is berthed and lifted
by principle of buoyancy
What is the advantage of heading and
benching method of tunnel construction?
It is easy to take corrective steps in the case
of excessive water
What is the advantage of concrete sleepers?
Improve the track modulus, maintain the
gauge quite satisfactorily.
What are fouling marks?:
The point fixed between a pair of converging
track to indicate possibility of side collision.
What are the various rail tuxtures � required
for the flat footed rail in wooden sleeper?
Bearin·g plate, dog spikes
For welding the raws in workshop which type
of welding is done
Oxy-acetylene welding
Which instrument is used for measuring the:
spot speed?
Enoscope
What. is�the … use ·of thB raii’ tonQs?
To remove dog spikes out of sleepers.
Which test in done for the determination of
softening point of bitumen?
Ring and ball test
In which type of pavement, reflection
cracking is observed?
Bituminous overlaid over cement coocrete
pavement.
What are frontal roads’
These are the roads which are provided to give
access to properties along an important
higrhway
