Explanation:

 Kolkata Metro was the first metro rail to be set up in India and the fifth one to be established in the entire Asian continent. Maintained by the Indian Railways, this underground metro network became functional in the year 1984. The metro rail stretches from the northern Kolkata at Dum Dum and continues through Park Street and Esplanade, in the center of the city, to the southern end, in Tollygunge. The entire length of Calcutta metro network is 16.45 km and there are a total of 17 stations on the entire stretch. Metro rail is one of the most convenient modes of traveling in a crowded city like Kolkata.