India and Bhutan will build the first cross-border railway lines connecting both countries, New Delhi announced Monday, with the $454-million project to be completed in four years. Indian foreign secretary Vikram Misri said his country, which is Bhutan's main trading partner, "has played a vital role" in the modernisation of the Himalayan kingdom's infrastructure and economy. An initial 69-kilometre railway, estimated to cost $390 million, will connect India's northeastern city of Kokrajhar to Bhutan's Gelephu. A second 20-kilometre railway line, expected to cost 5.77 billion rupees, will link Bhutan's of Samtse to Banarhat in eastern India.