The Kolkata Suburban Railway (colloquially called Kolkata local trains or simply locals) is a suburban and regional rail system serving the Kolkata metropolitan area and its surroundings in West Bengal, India. Its network has 458 stations and a track length of 1,501 km (933 mi) making it the largest suburban railway network in the country, and also one of the largest in the world. There are five main lines and 19 branch lines.

From Wikipedia