Railway EngineeringCivil Engineering

Lecture 1

SUIT Semester four

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Introduction

Definition of Railway

That part of transportation engineering involved in the planning, design,

development, operation, construction, maintenance, use, or economics

of facilities for transportation of goods and people in wheeled units of

rolling stock running on, and guided by, rails normally supported on

crossties and held to fixed alignment is known as railway engineering

A branch of engineering concerned with the design, construction,

maintenance, and operation of railways.

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Transportation Planning

The following surveys are carried out to finalize the selection of a

proposed railway line

Reconnaissance survey. Object of reconnaissance survey.

The First engineering survey which is carried out for the purpose of

laying a new railway line in any country is reconnaissance survey.

Main Object:

I. To acquire the general knowledge of the area as a whole.

II. To obtain information regarding the salient features of the territory.

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Importance of the reconnaissance

survey It helps in deciding a number of routes between two points

The information becomes very useful at the time of final selection of

the proposed routes.

The survey is highly rated and important and must be carried out by

an experienced engineer.

An engineer should possess good observational qualities and ability

to interpret the natural features.

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Factors to be kept in view during

reconnaissance survey The following factors should be kept in view during reconnaissance

survey.

1. Area. The reconnaissance survey should be carried out for the

entire area and not only along a line.

2. Existing roads. Alignment of the existing roads should not be

mistaken as suitable route for the survey. Road alignments are

seldom (not often) useful for the construction of a railway line.

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Continue

1. Assumption. The engineer should never declare his decision by

simply assuming the nature of the ground. He should personally

verify the details in the field.

2. Starting of route. The engineer should never reject a particular

route only because its start is bad i.e. with sudden rise or fall. He

must ascertain whether the route continues bad for a long distance.

3. Survey route. Each survey route should be surveyed independently

from either end.

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Continue

Ocular illusion. The following ocular illusions should be prevented.

i. Estimating wrong length.

ii. Estimating wrong curvature.

iii. Overlaps of hills which may appear as continuous ridge from a

distance, whereas it might have a valley at the overlap.

iv. In flat countries, the observer may observe a lake or river due to

mirage. In fact, no such thing exist there.

v. Revenue. The probable revenue from a new railway line 15 km on

each side should be ascertained.

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Instrument required for

reconnaissance survey The following survey instruments are required.

i. An aneroid barometer to determine approximate difference in

elevation.

ii. An abney level to obtain the gradient and angles of slope of the

ground up to 10.

iii. A prismatic compass to obtain the magnetic bearing of the proposed

routes or lines.

iv. A binocular to view the country.

v. A pedometer to get the distance traversed by a surveyor.

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The permanent way

The combination of rails, sleepers, fittings, ballast resting on sub

grade permanently, is called permanent way.

Temporary railway lines laid for the conveyance of construction

material and earth etc are called temporary tracks.

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Cross section of permanent way

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Requirement of an ideal permanent

way For high speed and better ridding qualities with nominal maintenance,

the following requirements are essential for an ideal permanent way.

1. The gauge should be correct.

2. The two rails in a straight track should be at the same level. On curves

the outer rail should be provided proper super elevation and there

should be proper transition at the junction of the straight and curve.

3. There should be a minimum friction in between the wheels of rolling

stock and the rail.

4. The design of permanent way should be such that the load of the train is

uniformly distributed.

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Continue..

1. The alignment should be free from kinks and irregularities.

2. The gradient should be even and uniform and any change of

gradient should be smoothened with a properly designed vertical

curve.

3. The track should possess certain amount of elasticity.

4. The track should be strong enough to withstand side thrust on

tangent lengthy and centrifugal force on curves, and also forces due

to expansion of welded rails.

5. The radii and superelevation should be properly designed and

maintained.

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1. Points and crossing should be properly designed and maintained.

2. Proper precautions should be taken to prevent creep likely to occur.

3. The various components of the track i.e. the rails, fittings, sleepers,

ballast and formation should be kept in healthy condition.

4. Renewal and replacement of damaged components of the

permanent way should be easy.

5. Various components of the permanent way, should possess anti-

theft qualities.

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End of Lecture one

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