Railway Engineering MCQ Quiz - Objective Question with Answer for Railway Engineering - Download Free PDF

The choice of different gauges of railway track depends upon following important factors and prevailing conditions in the region.

Traffic condition: If the intensity of traffic on the track is likely to be more, a gauge wider than the standard gauge is suitable.

Development of areas: To connect a remote location of a smaller population to the world, a narrow gauge may be suitable.

Cost of the track: It is directly proportional to the width of the gauge of railway track. As gauge width increases, the cost of ballast, sleepers, rails, etc increase proportionally.

Speed of Movement: The speed of the train is a function of the diameter of the wheel of a train, the diameter of a wheel is usually about 0.75 times the gauge width. Therefore, as the gauge width increases, wheel diameter increases and thus the speed of the train increases.

Explanation:

Elastic Rail Clip:

• This fastening system is commonly used with concrete sleepers in Indian Railways.
• It provides better stability and resilience, as it helps in keeping the rails in place by exerting a clamping force.
• The elasticity of the clip allows it to absorb vibrations and impacts, which improves the overall performance and durability of the track.

 Additional Information

1. Dog Spike: This is traditionally used with wooden sleepers. It is driven into the timber to hold the rails in place, but it is not suitable for concrete sleepers.

2. Fang Bolt: Typically used in some older or specific rail applications, it is not as common as the elastic rail clip for concrete sleepers in India.

3. Fish Plate: A fish plate is a metal plate used to join two rails together. It is not a fastening system for securing the rails to the sleepers but rather for connecting adjacent rails.

Explanation:

Primary function of a fish plate:

• A fish plate (also known as a rail joint or joint bar) is used to connect two rails together at a rail joint.

• It is bolted to the ends of adjacent rails to maintain continuity, alignment, and stability in the track.

• Fish plates are typically used in rail tracks to ensure the proper transfer of loads between connected rails and to prevent separation due to thermal expansion or mechanical stresses.

 Additional Information

• Rail continuity: Fish plates help in maintaining the continuous flow of forces along the track, allowing for smooth and stable operation of trains.

• Maintenance: They are often used to make repairs or provide a temporary solution when replacing rails.

Explanation:

• Rail transport is generally preferred over road transport for bulk goods movement because it is more energy-efficient, especially over long distances.
• Trains can carry a large quantity of goods with less energy consumption compared to trucks, especially when moving bulk commodities like coal, minerals, or agricultural products.
• The efficiency comes from the ability of trains to carry large loads with lower friction (due to steel-on-steel contact) and from the fact that trains are often more fuel-efficient per ton-mile.

Additional Information

1. Rail transport requires more energy due to heavier infrastructure.
   This is incorrect. While rail infrastructure is heavier than road infrastructure, it is more energy-efficient in terms of transporting large quantities of goods over long distances.

2. Rail transport is only suitable for short-distance bulk movement.
   This is incorrect. Rail transport is actually more efficient for long-distance bulk movement, such as between cities or across countries, because it can handle larger loads at lower costs over long distances.

3. Rail transport is always faster than road transport for all types of goods.
   This is incorrect. Rail transport is often slower than road transport for shorter distances or when speed is essential, like for perishable goods. Road transport provides more flexibility and quicker delivery for certain types of goods.

Explanation:

Standard Gauge for BG: In India, the Broad Gauge (BG) is defined as having a track gauge of 1676 mm (5 feet 6 inches). This is the most commonly used gauge in the country and accounts for the majority of the railway network.

• Significance of 1676 mm Gauge:

  • The 1676 mm Broad Gauge is used for long-distance passenger trains, freight trains, and high-speed services across India.

  • It provides better stability and allows for the operation of faster trains compared to narrower gauges (like meter gauge or narrow gauge).

  • The BG tracks can handle larger and heavier trains, which is essential for transporting both passengers and freight over long distances efficiently.

  • Over 80% of the total track length in India is Broad Gauge.

Additional Information Other Gauges in India:

• Standard Gauge (1435 mm): This is mostly used in some specialized or high-speed rail corridors, like the Mumbai-Ahmedabad bullet train project.

• Meter Gauge (1000 mm) and Narrow Gauge (762 mm or less): These are used for shorter, regional, or mountainous routes, though their use is gradually being replaced by Broad Gauge for better efficiency.

Explanation:

Ballast

It is the granular material that is placed and packed below and surrounding the sleeper.

Functions:

1. It transmits the load from sleepers to subgrade

2. Provide good drainage.

The characteristics of ballast are:

1. The depth of ballast for different type tracks is:

For BG: 20-25 cm

For MG: 15-20 cm

For NG: 15 cm

2. The quantity of stone ballast required for one-meter length of track for different type of tracks is as follow:

For BG – 1.036 m³.

For MG – 0.71 m³.

For NG – 0.53 m³.

3. The size of ballast depends on the type of sleeper and location of track and its is given as:

For Wooden sleeper - 5 cm

For Metal sleeper - 4 cm

For turnouts and cross-over - 2.5 cm

CONCEPT

Length of 1 rail(N) is taken as 13m

Number of sleepers = N + 3

Spacing of sleepers(S) = (length of 1 rail * 100) / number of sleepers (cm) 

Optimum depth of blast cushion = (S - W ) / 2

Given

Sleeper density = N+ 3 

width of the sleeper is 20.25 cm

CALCULATION

Number of sleepers = 13 + 3 = 16

Spacing of sleepers(S) = 13 X 100 / 16 = 81.25cm

Width of sleepers(W) = 20.25 cm

Minimum depth of blast cushion = (S - W ) / 2 

= (81.25 - 20.25) / 2 

= 30.5 cm (ans)

Explanation:

Sleeper density:

• It is defined as the number of sleepers required under one rail length of a railway track.
• It is expressed as (M + x) where M is the length of one rail in meters and x is constant whose value varies from 3 to 6. 
• In India generally, the sleeper density is taken as (M + 3) to (M + 6).

Calculation:

Given data:

Length of rail = 15 m

Number of sleepers per rail = 22

Expression for density =?

The number of sleepers required for 525 m track =?

Let, Sleeper density = n + x

22 = 15 + x

x = 7

Sleeper density = M + 7

Number of sleepers required for 525 m track = sleeper density × Number of rails on one side of the track

Number of sleepers required for 525 m track = (15 + 7) × (\({Length\, of\, track\over One\, rail\, length}\)) 

Number of sleepers required for 525 m track = 22× (\({525\over 15}\)) = 770

Number of sleepers required for 525 m track = 770

Concept:

Curve lead = 2GN

Where, G = Gauge of track

N = Number of crossing

Calculation:

Given,

N = 8.5

Gauge length for BG track (G) = 1.676 m

Explanation:

Given data:

Density of sleeper = M+5

For BG track length of one rail (\(l\)) = 13 m

Length of track (L) = 1 km or 1000 m

The number of fish plates required (N) =?

Number of rails required for 1 km of track (n) = \({Length\, of\, track(L)\over One\, rail\, length\,(l)}\)

Number of rails required for 1 km of track (n) = \({1000\over 13}=76.92 \approx77\)

Number of rails required for 1 km of track (n) = 77

Number of joints on both sides of the track (n'') = 2 × Number of rails required for the track (n)

Number of joints on both sides of the track (n'') = 2 × 77 = 154

Number of joints on both sides of the track (n'') = 154

Number of fish plates required for a given track (N) = 2 × Number of joints on track (n'')

Number of fish plates required for given track (N) = 2 × 154 = 308

Number of fish plates required for given track (N) = 308

Important Points

There are two fish plates and four bolts and four nuts required at one joint.

Concept

Grade compensation (GC) for BG = 0.04% per degree of curve

Calculation

Given,

Degree of curve D = 3° 

Ruling Gradient = 1 in 250 

So for 3° curve, compensation,

= 0.04 × 3 = 0.12%

∴ Ruling gradient \(= \frac{1}{{250}} \times 100 = 0.4{\rm{\% }}\)

∴ The actual ruling gradient considering the grade compensation of curvature = 0.4 - 0.12 = 0.28%

Concept:

The points and crossing are the vital components of track asset; necessary for diversion of traffic from one track to another track, such diversion may be necessitated for giving precedence to faster trains in the same direction, giving passage to a train moving in the opposite direction or for connecting places not on the direct line of the track.

Constituents of the points and crossing are explained below:

1. Turnout - The term denotes points and crossing with the lead rails.

2. Tongue rail - It is a tapered moveable rail, connected at its thickest end to the running rail.

3. Stock rail - It is the running rail, against which a tongue rail functions.

4. Switch - A pair of tongues with stock rail with necessary connections and fittings.

5. Points - A pair of tongue rail with their stock rails are termed as points.

6. Crossing - A crossing is a device introduced at the junction where two rails cross to permit the wheel flange of railway vehicle to pass from one track to another track.

7. Heel of the switch - It is an imaginary point on the gauge line midway between the end of the lead rail and the tongue rail in case of loose heel switches In case of fixed heel switches, it is a point on the gauge line of tongue rail opposite the centre of heel block.

8. Lead - The track portion between heels of the switch to the beginning of crossing assembly is called the lead.

9. Turn – in – curve - The track portion between the heel of crossing to the fouling marks is called the turn – in – curve.

For points & crossing, the maximum of nominal size of the ballast is 25 mm.

Other Points:

1. Points & crossing provide flexibility of movement by connecting one lien to another according to requirements.

2. They also help for imposing restrictions on turnouts which further retards the speed of the train.

3. The main function of ballast is to hold the sleepers and convert line load to uniformly distributed load.

Concept:

Classification of the signal based on location characteristics:

(1) Reception signal: 

Signals which control the reception of trains into a station.

These signals are related to the station section (station section is that section that comes under the direct control of that station and it is this particular section in which trains remain stationed at that platform).

Here, also we have two types of signals:

• Outer signal
• Home signal

​Outer signal:

The outer signal is the first stop signal before the train enters from the block section to the station section.

Home signal:

The home signal is just provided at the door of the station (signal just before reaching the platform).

(2) Departure signal:

When the train standing on the platform and has to depart, at that location the signal provided to dispatch the train from the station is known as the departure signal.

Departure signals can be subdivided into two types:

• Starter signal
• Advance signal

(3) Routing signals:

It is a group of semaphore signals placed at the facing point of a cone or a number of turnouts.

(4) Shunting signal:

Used for shunting operations (It is the slow operations which take place in station yard) in station yards.

On Indian railways standard length of BG rail = 13 m 

So, total no. of rail required in 1.024 km or 1024 m

= 1024/13 = 78.78 = 80 (in round figure)

Sleeper density = M + 7

M = length of rail

So, sleeper density = 13 + 7 = 20

No. of sleepers = 20 × 80 = 1600