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

Explanation:

1. Definition of Rail Wear
   Rail wear refers to the gradual loss of material from the rail surface due to friction, impact, and stress from repeated wheel contact. It affects the rail’s profile, strength, and alignment over time.

2. Maximum Wear in Sharp Curves
   On sharp curves, the outer rail experiences more lateral force due to centrifugal action, and the flange of the wheel exerts greater pressure, causing gauge face wear. This is the most severe location for rail wear.

3. Types of Rail Wear

   • Top wear: due to vertical loading from train wheels.

   • Side (gauge face) wear: from lateral thrust in curves.

   • End wear: due to improper jointing or impact at rail ends.

   • Corrugation: formation of waves or undulations due to vibration.

4. Factors Influencing Rail Wear

   • Traffic volume and speed

   • Track geometry (curves vs. tangents)

   • Rail material and hardness

   • Axle loads and wheel profiles

   • Lubrication and maintenance practices

 Additional InformationOther Types of Rail Damage 

• Crushing of Rail Head:  Happens under high axle loads, especially if material is soft or under-lubricated. It leads to deformation of the rail crown, which affects riding comfort and increases the risk of derailment.

• Rail Fractures and Cracks: Initiated by internal flaws or fatigue, aggravated by repeated impact loading. Cracks often originate from bolt holes, fishplate areas, or welded joints.

• Shelling and Spalling: Shelling occurs when small pieces of metal flake off due to internal fatigue. Spalling is surface chipping due to impact or stress concentrations, often seen near switches or crossings.

• Rail Buckling: Common in extreme heat, when thermal expansion causes longitudinal stress. If rails are not adequately anchored, it results in track misalignment and severe safety hazards.

• Plastic Flow: Repeated stress can cause metal flow on the rail surface, especially in soft rails. This leads to change in rail profile, requiring grinding or replacement.

• Squats and Corrugations: Squats are small surface defects from rolling contact fatigue. Corrugations are wave-like wear patterns caused by vibration, leading to noise and uneven running surfaces.

Explanation:

Wire Claw

• The wire claw is a hand-held steel tool used to loosen and remove caked ballast from between and around the sleepers, especially in sections with limited access.

• It has curved, claw-like prongs that are ideal for reaching tight spots where machines cannot operate effectively.

• It ensures proper cleaning before re-tamping and helps maintain drainage and track performance.

Jim Crow

• A Jim crow is a manual or hydraulic rail bender, used to bend rails horizontally during laying of curves or to correct alignment deviations.

• It has a strong frame with a screw jack mechanism to apply lateral force to the rail web or head.

• It is essential during the initial laying of curved tracks and for adjusting rails during maintenance.

 Beater

• A beater is a tamping tool used to compact ballast underneath sleepers manually. It is typically a flat or round heavy steel plate attached to a long handle.

• Track workers strike the ballast repeatedly to eliminate voids under sleepers and improve track stability.

• It is mainly used in small-scale maintenance where mechanized tamping machines are not employed.

Mallet

• A mallet is a soft-faced hammer, usually made of wood, rubber, or plastic, used for sounding sleepers to detect voids or loose support.

• When a sleeper is tapped, a hollow sound indicates inadequate ballast support, which signals the need for re-tamping.

• It prevents over-tamping and ensures maintenance is only carried out where required, saving time and resources.

 Additional InformationTrack Gauge

• Used to measure and maintain the correct rail gauge (distance between inner faces of rails).

• It ensures track safety and prevents derailment.

Lining Bar

• Used to adjust the lateral position of rails to correct alignment during track laying or maintenance.

Fish Bolt Spanner

• A large wrench used to tighten or loosen bolts connecting rail joints (fish plates), ensuring strong and aligned rail connections.

Rail Tong / Rail Lifter

• Used to lift and position rails manually during replacement or realignment operations.

Explanation:

Flangeway Clearance

• Flangeway clearance is the gap provided between the running rail and the check rail to allow the wheel flange to pass through safely without interference.

• It is critical near crossings and turnouts, especially where the wheels might otherwise derail due to lack of continuous rail support.

• This clearance helps in guiding the wheel along the intended path and avoids collisions or excessive wear between the flange and the check rail.

 Additional Information Check Rail

• A check rail (also called a guard rail) is laid parallel to the running rail, usually on the inner side of curves and crossings.

• Its function is to guide the wheel flange and prevent derailment at locations like crossings, bridges, or sharp curves.

• It works in coordination with flangeway clearance to ensure smooth passage of wheels.

Switch (Turnout)

• A switch or point is a movable arrangement in track that allows a train to be diverted from one track to another.

• It consists of tongue rails (switch rails) and stock rails, with the tongue rail moving laterally to connect to either of the diverging tracks.

• The point of movement is called the toe of switch.

Explanation:

Broad Gauge (1676 mm)

1. Broad Gauge is the standard for most of Indian Railways with a track width of 1676 mm. It allows for higher speeds, better stability, and greater load-carrying capacity. Suitable for main lines, high-speed corridors, and long-distance routes.

2. It supports heavier axle loads and larger train dimensions, improving efficiency. Both passenger and freight trains run more smoothly on this gauge. Major express and superfast trains operate on Broad Gauge tracks.

3. The Unigauge policy promotes Broad Gauge as the uniform standard in India. This eliminates transshipment and enables seamless connectivity across zones. It simplifies maintenance and operational planning across the network.

 Additional InformationMeter Gauge (1000 mm)

1. Meter Gauge has a track width of 1000 mm, commonly used in earlier rail development. It was preferred due to lower construction costs and suitability for light traffic. Mostly found in rural and low-density routes in past decades.

2. It has lower speed and load capacity than Broad Gauge, limiting efficiency. Trains running on meter gauge are generally smaller and slower. It cannot handle the same volume as broader gauges.

3. Meter Gauge is being gradually replaced under the Unigauge policy.
   Many routes have already been converted to Broad Gauge for standardization. This helps improve network connectivity and operational flexibility.

Narrow Gauge (762 mm and 610 mm)

1. Narrow Gauge includes tracks less than 1000 mm, commonly 762 mm or 610 mm.It was used in hilly, forested, or difficult terrains where wider gauges were impractical. Construction and maintenance are cheaper due to lighter infrastructure.

2. These gauges are suitable for light traffic and short-distance railways.
   Rolling stock is smaller, and speeds are significantly lower. Used for heritage lines, rural lines, and industrial railways.

3. Examples include Darjeeling Himalayan Railway (610 mm) and Matheran Hill Railway (610 mm). These lines are often tourist attractions and preserved as heritage sites. They demonstrate engineering solutions in mountainous regions.

Concept:

Sleeper density is denoted as n + x.

Here n + x denotes the number of sleepers to be used for one rail length.

n = length of one rail.

Calculations:

Given:

• Gauge (G) = Broad Gauge (BG) = 1.676 m

• Sleeper density =$(n+4)$, where n = length of one rail in meters

• Length of one rail = 13 m

• Track length = 1 km = 1000 m

So, sleeper density = 13 + 4 = 17 sleepers per rail

Number of rails in 1 km \(=\frac{1000}{13}=76.92rails\)

Total number of sleepers\(=76.92\times17=1308 \) sleepers

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.

Concept:

The yard is defined as a system of tracks laid within definite limits for various purpose such as storing of vehicles, making up trains, dispatch of vehicles, etc. over which movements, not authorized by timetable, may be made subject to prescribed rules and regulations and signals.

For convenience, the classification of railway yards is done following five categories are as follows:

i) Passenger Yards

ii) Goods Yards

iii) Marshalling Yards

iv) Locomotive Yards

v) Sick Yards

Marshalling yards:

Marshalling Yard is a place where goods trains are received, sorted, reformed and dispatched.

Functions of marshalling yards:

a) Reception

b) Sorting

c) Departure

Types of marshalling yards:

a) Flat Yard- used where space is limited

b) Gravitational yard - Used where the ground is sloppy.

c) Hump yard - Used when trains are required to be pushed against a hump.