Railway Building Engineering Practice Exam paper
Question and Model Answers
a) Write two merits of roadways over railways.
Ans :-
1. They provide door to door service.
2. In hilly or mountainous region, roads are the only means of conveyance.
3. They help to provide medical aid to remote places.
4. They transport men and material from one part to other speedily and easily.
5. A number of small units like rickshaw, cars, scooter etc are available for
personalized transport.
6. The roads can be improved in terms of width and nature of surface as the demand
of traffic grows.
7. Starting and destination points need not be necessarily defined.
b) List the types of rail gauge.
Ans :-
1. Broad gauge = 1676 mm
2. Meter gauge 1000 mm
3. Narrow gauge = 762 mm
4. Light gauge =610 mm
c) Define cant deficiency and negative cant.
Ans :-
Cant deficiency: The difference between the equilibrium cant, necessary for maximum
permissible speed on a curved railway track and the actual cant provided is known as cant
deficiency.
Cant deficiency: is the amount by which the actual superelevation falls short of the
equilibrium superelevation.
Negative cant: The elevation of outer rail below the inner rail of a turnout or branch track
at the place where it meets the main track on a curve is called as negative cant or negative
super elevation.
d) Give two purposes of station yard.
Ans :-
I. Passenger bogie yards provide facilities for the safe movement of the passengers
and vehicles for the passenger.
II. Goods yard provide facilities for receiving, Loading, Unloading and delivery of goods
and movement of goods vehicle.
III. Marshalling yards provide facilities of receiving train and other loads, sorting out
and forming new trains and their dispatch onwards.
IV. Locomotive yards provide facilities for coaling, watering, repairing, oiling, cleaning
etc for servicing and maintenance of locomotive.
e) Write the necessity of temporary bridge.
Ans :-
I. These bridges help in facilitating the construction of permanent bridges.
II. When the bridges are required for shorter period or at the earliest time for
temporary purpose.
III. Temporary bridges are required under emergency conditions.
IV. Temporary bridges are easy in construction and suitable for light traffic.
f) List out the components of left hand turnouts.
Ans :-
I. Stock rails
II. Lead rails
III. Check rails
IV. Splice rails
V. Tongue rails
VI. Wing rails
VII. Stretcher bar
VIII. Point rails
IX. Toes of switch
X. Throw of switch
XI. Nose of crossing
XII. Main track
XIII. Branch track
XIV. Crossing angle.
g) Classify tunnels based on its purpose.
Ans :-
I. Railway tunnel
II. Highway tunnel
III. Navigation tunnel
IV. Subway tunnel
V. Pedestrian tunnel
VI. Water supply tunnel
VII. Sewer tunnel
VIII. Hydro – electric power tunnel
IX. Tunnels for industrial use.
X. Tunnels for intake and conveying public utilities.
Q. 2 Attempt any THREE of the following.
a) Write the ideal requirements of permanent way.
Ans :-
Ideal requirements of permanent way:
I. The gauge should be uniform and correct.
II. The alignment should be correct and the rails should be at the same level on
straight portion.
III. The track should be resilient. (i.e. there must be a certain amount of elasticity in the
track)
IV. The gradient should be uniform and any change in gradient should be followed by a
smooth curve.
V. The track should have enough lateral strength so that alignment is maintained.
VI. Points and crossings and rail joints should be perfectly designed and maintained.
VII. The radii and superelevation on curves should be properly designed and
maintained.
VIII. The drainage system must be perfect.
IX. Fixtures and fastenings should be strong enough to withstand the stresses.
X. It should not have excessive rail joints.
XI. There should be adequate provision for easy renewals and replacements.
XII. The load of the train should be distributed uniformly over the permanent way.
b) Explain the functions of ballast.
Ans :-
I. To distribute uniformly the load from the sleepers over a large area of formation or
subgrade.
II. To hold the sleepers in their correct position and preventing their lateral
movements.
III. To prevent the growth of weeds inside the track.
IV. To drain off the rain water from the track quickly and to provide well drained
foundation bed immediately below the sleepers.
V. To provide cushion effect to the track since it acts as an elastic medium between
the sleepers and the formation.
VI. To provide a firm bed for the sleepers to rest upon.
VII. To protect the top surface of formation.
VIII. To provide an easy method for track adjustment and gradients without any
disturbance to formation.
c) Classify the bridges based on:
Ans :-
I. Span of bridge
II. Purpose of bridge
Classification of bridges according to span.
I. Culverts
II. Minor bridges
III. Major bridges
IV. Long span bridge
Classification of bridges according to purpose:
I. Aqueducts
II. Viaducts
III. Foot Bridges
IV. Highway Bridges
V. Railway Bridges
d) Discuss the factors affecting selection of rail gauge.
Ans :-
A. Cost of construction.
There is little increase in the initial cost if we select a wider gauge (say B. G.)
This is due to the following reasons:
I. The cost of earthwork, ballast, sleepers, rails etc. would increase with increase in
gauge width.
II. There is little increase in the acquisition of land for permanent track with increase
in gauge.
III. The cost of rolling stock is independent of the gauge used. For the same volume of
traffic.
B. Volume and nature of traffic
It is evident with greater traffic volume and greater load carrying capacity, the trains
should be run by a better traction technique or by better locomotive.
C. Development of the area
Narrow gauge can be used to develop the thinly populated areas by joining the poor
developed areas with developed or urban areas.
D. Physical features of the country.
Use of narrow gauge is warranted in hilly regions where broad and meter gauge are
not possible due to steep gradients and sharp curves.
E. Speed of movement
The speed of a train is almost proportion to the gauge. Speed is the function of
diameter of wheel, which in turn is limited by the gauge. The wheel diameter is
generally 0.75 times that of gauge. Lower speeds discourage the customers and so far
maintaining high speeds, the broad gauge are preferred.
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