The Correct Answer is Vivek Express - Dibrugarh to Kanyakumari. Explanation & Key Takeaways: • On the Indian Railways network, Vivek Express is a series of express trains. • These trains were announced by the then Railway Minister in the Railway Budget of 2011-12. • These trains were launched to celebrate Swami Vivekananda's 150th birthday, in 2013. • It has the longest route on the Indian Railway network in terms of distance and time and is actually the 24th longest in the world. Important Notes: • The Himsagar Express is a weekly Indian Railway express train that runs from Kanyakumari in Tamil Nadu, India's southernmost state, to Shri Mata Vaishno Devi Katra in Jammu and Kashmir, India's northernmost state. In terms of distance and time, it is the third longest-running train on the Indian Railways at present. • A weekly train running between Katra and Mangalore Central is the Navyug Express or the "New-Era" Express. The distance of 3,685 km takes around 68 hours and is the fifth-longest distance travelled by any Indian train.