Introduction to Railway Engineering
Define Gauge in
Railway Track:-
The Gauge of a railway track
is defined as the clear distance between the inner or running faces of two
track rails. The distance between the inner faces of a pair of wheels is called
the ‘wheel
gauge’.
Different Gauges in India & Abroad:-
In 18th century, the British Railway were using the flanges on the outside of rails and the gauge was
defined as the distance between the outer faces of the rails. The gauge then maintained
was 5’ (1.524 m). Subsequently, the adoption of flanges inside the wheel on
rails changes the definition of gauge. The position of rails of track was not
changed in view of economy and clear distance between inner faces was defined
by gauge.
So Present gauge = Past gauge – 2
× rail width at top.
= 1.435 m.
A gauge of 1.435 m, is the
standard gauge in most of the countries even today.
In India, the East India Company adopted
1.676 m. gauge as the standard gauge.
Thus, in India the
following gauges are used:-
|
Type of
Gauge
|
Gauge Width
|
|
Standard Gauge (B.G.)
|
1.67 m
|
|
Metre Gauge (M.G.)
|
1.0 m
|
|
Narrow Gauge (N.G.)
|
0.762 m
|
|
Feeder Track-Gauge or Light Gauge (L.G.)
|
0.610 m
|
Gauges on World
Railway or Gauges in Different Countries:-
|
S. No.
|
Type of
Gauge
|
Gauge
Width
|
Countries
|
|
1.
|
Standard Gauge
|
1.435 m
1.451 m
|
U.K., U.S.A., Canada etc.
Whole of Europe except Russia, Spain And Portugal.
|
|
2.
|
Metre Gauge
|
1.0
m
1.069 m
|
France, Switzerland, Argentina
Japan, Australia, South Africa etc.
|
|
3.
|
Narrow Gauge
|
0.762 m
0.610 m
|
India & U.K.
India & South Africa.
|
Selection of Gauge
or Choice of Gauge:-
The gauge choice
depends upon the following factors:
1). Cost of
construction:-
There is little increase in the initial cost if we select a
wider gauge (B.G.) this is due to the following reasons;
(a) The cost of bridge, tunnels, station
buildings, staff quarters, signals, cabins and level crossings is the same for
all gauges.
(b) The cost of the earth work (in making
embankments and cuttings), ballast, sleepers, rails, etc. would proportionally
increase with increase in gauge width.
(c)
There is little proportional increase in the acquisition (something acquired)
of land for permanent track with increase in gauge.
(d) The Cost of rolling stock is
independent of the gauge used for the same volume of traffic.
We can, therefore,
conclude that there is not an appreciable (Enough to be estimated or measured) increase
in cost due to increase in width of gauge.
2). 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 locomotives. For heavier load and high speed, the wider gauges are
required because subsequently the opening cost per ton-km is less for higher
carrying capacity.
3). Development
of the Areas: -
Narrow gauges can be used to develop the thinly populated areas
by joining the under developed areas with developed or urbanized (Made urban in
nature) areas.
4). Physical
features of the country: -
Use of narrow gauge is warranted in hilly region
where broad and metre gauges are not possible due to steep gradients and sharp
curves. In plains also, where high speed is not required and the traffic is
light, N.G. is a right choice.
The speed of a train is
almost proportional 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 the gauge. Lower speed discourage
the customers, and so for maintaining high speeds, the Broad gauge is
preferred.
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