Question

How many gauges of railway tracks are there in India?

Answer 1

Hint: The clear minimum vertical distance between the inner sides of the two tracks is known as the railway gauge. That is, the distance between two tracks on any railway route is called a railway gauge.

Complete answer:
Around sixty percent of the world's railways use a standard gauge of 1,435 mm. There are mainly four types of railway gauge used in India, which are: Broad gauge, Narrow gauge, Standard gauge (for Delhi Metro), and Meter Gauge.
Broad Gauge:
A broad-gauge is also known as a wide gauge or large line. The distance between the two tracks in these railway gauges is 5 ft 6 in (1676 mm). Any gauge wider than the standard gauge or 1,435 mm is called a broad gauge. Broad gauge railways are also used on ports for cranes etc. This gives better stability and they are even better than the thinner gauges.
Standard Gauge:
The distance between two tracks in this type of railway gauge is 4 ft 8½ inches (1435 mm). In India, standard gauge is used for urban rail transit systems like Monorail, Metro, and Tram. The only standard gauge line in India till 2010 was the Kolkata tram system. All metro lines coming in the urban areas are made only in the standard gauge because it is very easy to get rolling stock for the standard gauge as compared to the Indian gauge.
Metre Gauge:
The distance between the two tracks is 3 ft 3 3/8 inches or 1,000 mm. The meter gauge lines are made to reduce the cost. Under project Unigauge, all the meter gauge lines except the Nilgiri Mountain Railway which is legacy run on a meter gauge in India will be converted into broad gauge.
Narrow Gauge:
The small railway gauge is known as a Narrow gauge or a small line. The narrow-gauge railway is the railway track, in which the distance between two tracks is2 ft (610 mm) and 2 ft 6 in (762 mm). In 2015, there was a 1,500 km narrow gauge rail route, which is considered to be about two percent of the total Indian rail network.

Note: There are factors that affect the Railway Gauge. Those are:
Traffic conditions, Poor areas development, Cost of the track: Speed of the train, etc.