Here is the list of the ten longest-running trains in the country operated by the Indian Railways.
1: Dibrugarh - Kanyakumari Vivek Express is the longest-running train in the country. The weekly train runs close to 83 hours across eight states and covers a distance of over 4,200 kilometres and traverses through eight states in India. (Wikimedia Commons)
2: Aronai Superfast Express is the second longest-running train in India. It operates between Thiruvananthapuram Central and Silchar serving the 8 states and covers close to 4,000 km. (Wikimedia Commons)
3: Thiruvananthapuram Central - Silchar Express is a weekly train that covers close to 4,000km and connects Thiruvananthapuram Central to Silchar and travels through Assam, West Bengal, Bihar, Jharkhand, Odisha, Andhra Pradesh, Tamil Nadu and Kerala. (Wikimedia Commons)
4: Himsagar Express is a weekly express train running between Kanyakumari, Tamil Nadu and Shri Mata Vaishno Devi Katra, Jammu and Kashmir. The train covers a distance of over 3,700 km and transverses twelve Indian states.
5: The Navyug Express is a weekly train running between Katra and Mangalore Central. It covers a distance of close to 3,700 km.
6: Tirunelveli - Shri Mata Vaishno Devi Katra Express is a bi-weekly train service connecting the states of Tamil Nadu with the union territory of Jammu & Kashmir. The train covers a distance of over 3,600 km and transverses twelve Indian states.
7: New Tinsukia-Bengaluru Weekly Express is a weekly superfast train which connects Tinsukia, the easternmost town of Assam with the South Indian metropolis Bengaluru. The train covers a distance of over 3,600 km. (indiarailinfo.com)
8: Kochuveli - Amritsar Weekly Express is a superfast train of the Indian Railways connecting Kochuveli in Kerala and Amritsar Junction of Punjab. The train covers close to 3,600 km during its trip. (indiarailinfo.com)
9: Bangalore Cantonment - Agartala Humsafar Express is a fully air-conditioned express train, connecting Bangalore Cantonment in Karnataka and Agartala, the capital city of Tripura by travelling over 3,500 km. (Wikimedia Commons)
10: Kochuveli Dehradun Superfast Express runs between Kochuveli and Dehradun. It covers 9 states of the country including Kerala, Karnataka, Goa, Maharashtra, Gujarat, Rajasthan, Delhi, Uttar Pradesh and Uttarakhand. The train covers a distance of over 3,400 km. (indiarailinfo.com)