Which of the following factors govern the choice of the gauge ? i) volume and nature of traffic ii) speed of train iii) physical features of the country The correct answer is A. only (i) B. both (i) and (ii) C. both (ii) and (iii) D. (i), (ii) and (iii)

The correct answer is D. (i), (ii) and (iii).

The gauge of a railway track is the distance between the inside edges of the two rails. The most common gauges are 1,435 mm (4 ft 8 1⁄2 in), 1,520 mm (4 ft 11 1⁄2 in), 1,600 mm (5 ft 3 in), 1,067 mm (3 ft 6 in), and 914 mm (3 ft 0 in).

The choice of gauge is governed by a number of factors, including:

• The volume and nature of traffic: A wider gauge can accommodate more traffic and heavier trains.
• The speed of train: A wider gauge allows for higher speeds.
• The physical features of the country: The gauge must be compatible with the terrain and the existing infrastructure.

In some cases, political or economic factors may also influence the choice of gauge. For example, the Soviet Union adopted a wider gauge (1,520 mm) in order to be independent of the European rail network.

The gauge of a railway track is an important factor in the design and operation of a railway system. The correct gauge must be chosen to ensure the safe and efficient movement of trains.