Railways is a mean of land transport to carry passengers, goods etc., from one place to another. The railway lines are classified on the basis of the importance of routes, traffic carried and maximum permissible speed on the routes. As such Indian railways are classified into the following main categories:
a) Trunk Routes
b) Main Lines
c) Branch Lines
Indian railways are also classified as based on speed criteria and divided into the following groups:
- Group A
In this group consists of those trunk routes on which the trains runs at more than 160 kmph.
- Group B
In this group, the maximum speed limit of the trains is limited to 130 kmph.
- Group C
All the routes whether Broad Gauge or Meter Gauge where maximum permissible speed is limited to 100 km p/h fall in this group.
- Group D
All the routes where the speed limit is less than 100 kmph are taken into this group.
Terms are Used in Railways
Indian Railways are classified into the following terms:
1. Railway Track
It is the structure which consists of rails fitted to sleepers resting on ballast and sub grade.
These are steel girders on which movement of locomotives and other railway vehicles is carried.
It is the granular material of crushed stones provided under and around the sleepers to transfer loads coming over it to a larger area and provides elasticity to the track.
These are the wooden or steel members laid transversely under the rails of their support.
Formation is the sub grade prepared to receive the ballast.
7. Coning of Wheels
The wheels of railway vehicles are coned at a slope of 1 in 20 to prevent from rubbing the inside face of the rail head and to prevent lateral movement of the axle with its wheels.
It is the departure of the railway track from the level. When the track rises it is called an up gradient and when the track falls below in the direction of movement it is down gradient.
8. Super-elevation or Cant
On curves, the level of outer rail is raised above the inner rail by a certain amount to counter act the effect of centrifugal force. So the raising of outer rail over inner one is called super-elevation or cant.
9. Points and Crossing
These are the arrangements by which different routes either parallel or diverging are connected to make the movements of the trains from one track to another.
10. Junction Station
When two or more lines meet at a station it is called junction station.
These are the system of tracks at a station to be used for storing, sorting and dispatching of vehicles and making up trains.
These are the techniques by means of which the movements of various trains is controlled to maintain safety for the trains.
It is the maximum distance between the running or gauge faces of the two rails. Indian railways are divided into following three gauges:
- Broad Gauge
When the distance between the running faces or gauge faces is 1.676 meters, it is called Broad Gauge.
- Meter Gauge
The gauge of a track in which the distance between the running faces of two track rails is one meter is called meter gauge.
- Narrow Gauge
The distance between the running faces of two track rails, in case of narrow gauge meter is either 0.762 meters or 0.61 meters.