Infrastructure Engineering-Part-5

Infrastructure Engineering
& Construction Techniques
Department of Civil Engineering
Indira College of Engineering and Management Pune.
Unit-1_Part-5

Outline_Recap
1. Salient features of smart city
2. Permanent way,
3. Track structure of BG,
4. Functions of rail
7/17/2020Prof. Vijay Kumar Saini 2

Outline
❖Standard rail,
❖Tilting of rail,
❖Coning of wheels,
❖Types of sleepers,

1.1 Standard Rail
▪A standard-gauge railway is a railway with a track gauge of 1,435 mm (4 ft 8 1⁄2 in).
▪The standard gauge is also called Stephenson gauge after George Stephenson, International
gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe

1.2 Various Gauges
▪Broad Gauge
▪Standard Gauge
▪Metre Gauge
▪Narrow Gauge

1.3 Factors Affecting choice of a Gauge
1. Traffic Condition
2. Development of poor areas
3. Cost of track
4. Speed of Movement
5. Nature of Country

1.3 Benefits of Uniformity of Gauges
1. Difficulties to passengers
2. Difficulties for sending goods
3. Inefficient use of rolling stock
4. Difficulty in war
5. Equipment at station
6. Hindrance for future conversion

2.1 Coning of Wheels
▪In coning of wheel the tread or rim of wheels of railway vehicles is made in the shape of a
cone with the slope of about 1 in 20.
▪It maintains vehicle in the central position w.r.t. the track. On straight track, portions of
wheels running on track have same diameter.
▪While on curved path, the outer wheel has to cover larger distance than the inner wheel.
Thus, the portions of wheels running on track have different diameters which help in
smooth running of wheels.

2.1 Coning of Wheels

2.2 Coning of Wheels_Advantages
▪Smooth riding - Help vehicle to negotiate curves smoothly
▪Reduces wear and tear of wheel flanges. Damage is caused because of the friction action of
rims with inner faces of the rail top.
▪It gives an option of lateral drift of the hinge with its wheels.
▪It prevents, to some extent, the slipping of the wheels.

2.3 Coning of Wheels_Disadvantages
▪The pressure on the horizontal component of force near the inner edge of outer rail has a
tendency to wear the rail quickly
▪The horizontal component has to turn the rail outwards and hence the gauge may be
widened
▪If no base plates are provided, sleepers under the outer edge of the rail may be damaged

3.1 Tilting of Rails
▪In order to minimize the disadvantages caused by coning of wheels, the rails are tilted
inwards at an angle of 1 in 20.
▪This reduces wear on the rail as well as on the tread of the wheel.
▪Tilting of rails can be achieved by:
✓Adzing of Sleepers
✓Use of Canted Base Plate

3.2 Tilting of Rails_Advantages
▪It maintains the gauge properly
▪The wear at the head of rail is uniform
▪It increases the life of sleepers and rails.

4.1 Sleepers
▪Railway sleepers, also called railroad ties, railway ties or crossties, are an important railway
component. Generally, the rail sleeper is always laying between two rail tracks to keep the
correct space of gauge.

4.2 Sleepers_Functions
▪ To hold the rails to proper gauge in all situations. i.e. exact gauge along straights and flat curves, slightly loose on sharp curves
and slightly tight in diamond crossings.
▪ To support the rails firmly and evenly throughout.
▪ To distribute the load transmitted through rails over large area of ballast underneath or to the bridge girders.
▪ To hold the rails to proper level in turnouts and crossovers, and at 1 in 20 in ward slope along straight tracks.
▪ To provide and elastic medium between the rails and ballast and also to absorb the vibrations caused due to moving axle loads.
▪ To maintain proper alignment of the track. On curves proper cant is provided by raising the outer rail and tamping the required
quantity of ballast bellow the rails.
▪ To provide the general stability of the permanent way throughout.
▪ To provide the insulation of track for the electrified for signaling.
▪ To provide easy replacement of the rail fastenings without any serious traffic disturbances.

4.3 Sleepers_Wooden
▪Wooden sleeper advantages:
✓Easy to manufacture and handle
✓Electrically insulated
✓Easily adapted to non-standard situations
▪Disadvantages:
✓Non reusable
✓Expensive of the limit wood resource

4.4 Sleepers_Steel
▪Steel sleeper advantages:
✓Easy to install and manufacture
✓Handle more weight
▪Disadvantages:
✓Sensitive to the chemical attacks
✓Hard to maintain
✓Low transverse resistance

4.5 Sleepers_Concrete
▪Concrete sleeper advantages:
✓Cheaper
✓Easier to obtain
✓Less maintenance required
✓Longer service life
▪Disadvantages:
✓Hard to handle due to large weight
✓Difficult to maintain longitudinal level due to higher inertia moment and lower elasticity

5. Railyway Engineering_NPTEL
▪Railway Engineering
Dr. Rajat Rastogi
Department of Civil Engineering
IIT Roorkee

Infrastructure Engineering-Part-5

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