<P> As of 2011, the total railway route length is around 4,481 km (2,784 mi). Kolkata is the headquarters of three zones of the Indian Railways--Eastern Railway and South Eastern Railway, and the Kolkata Metro, which is the newly formed 17th zone of the Indian Railways . The Northeast Frontier Railway (NFR) serves the northern parts of the state . The Kolkata metro is the country's first underground railway . The Darjeeling Himalayan Railway, part of NFR, is a UNESCO World Heritage Site . </P> <P> Netaji Subhas Chandra Bose International Airport at Dum Dum, Kolkata, is the state's biggest airport . Bagdogra Airport near Siliguri is a customs airport that offers international service to Bhutan and Thailand, besides regular domestic service . Kazi Nazrul Islam Airport, India's first private sector airport, serves the twin cities of Asansol - Durgapur at Andal, Bardhaman . </P> <P> Kolkata is a major river port in eastern India . The Kolkata Port Trust manages the Kolkata and the Haldia docks . There is passenger service to Port Blair on the Andaman and Nicobar Islands and cargo ship service to ports in India and abroad, operated by the Shipping Corporation of India . Ferries are a principal mode of transport in the southern part of the state, especially in the Sundarbans area . Kolkata is the only city in India to have trams as a mode of transport, and these are operated by the Calcutta Tramways Company . </P> <P> Several government - owned organisations operate bus services in the state, including the Calcutta State Transport Corporation, the North Bengal State Transport Corporation, the South Bengal State Transport Corporation, the West Bengal Surface Transport Corporation, and the Calcutta Tramways Company . There are also private bus companies . The railway system is a nationalised service without any private investment . Hired forms of transport include metered taxis and auto rickshaws, which often ply specific routes in cities . In most of the state, cycle rickshaws, and in Kolkata, hand - pulled rickshaws and electric rickshaws, are used for short - distance travel . </P>

The country of the world which is equal in area of west bengal