The 15645 / 46 Lokmanya Tilak Terminus–Dibrugarh Express is an Express train belonging to Indian Railways Northeast Frontier Railway zone that runs between Lokmanya Tilak Terminus of Maharashtra and Dibrugarh of Assam in India..It holds the record of 19th Longest train service of Indian Railways. It is also called Dadar Express. It operates as train number 15645 from Lokmanya Tilak Terminus to Dibrugarh and as train number 15646 in the reverse direction, serving the states of Maharashtra, Madhya Pradesh, Uttar Pradesh, Bihar, West Bengal, Nagaland & Assam.