The 15909 / 15910 Avadh Assam Express is an express train operated by Northeast Frontier Railway that runs between Dibrugarh railway station of Dibrugarh, Assam and Lalgarh Junction of Bikaner, Rajasthan in India.

[1] It operates as train number 15909 from Dibrugarh to Lalgarh Junction and as train number 15910 in the reverse direction, serving the nine states of Assam, Nagaland, West Bengal, Bihar, Uttar Pradesh, Delhi, Haryana, Punjab and Rajasthan.

[2] A metre-gauge train from Lucknow to Guwahati Awadh Tirhoot Mail used to run until gauge conversion took place and the BG Avadh Assam Express was started in late 1980s.

As is customary with most train services in India, Coach Composition may be amended at the discretion of Indian Railways depending on demand.

As the average speed of the train is below 55 km/h (34 mph), as per Indian Railways rules, its fare does not include a superfast surcharge.