Train no. 15909 & 15910/Dibrugarh-Lalgarh Avadh Assam Express is the longest distance running Mail/Express category train in Indian Railways
It takes 66 hours 35 min, approx 3116 km and daily operating Express Category train.
It covers 8 states and 1 union territory including Assam, Nagaland, West Bengal, Bihar, Uttar Pradesh, Delhi, Haryana, Punjab, and Rajasthan.
Connecting Assam’s Commercial Hub, Capital City Area North Eastern Part to Bikaner Outer City Lalgarh North Western Part)
Delays can be expected due to numerous no. of stops, how many trains overtake depending upon particular Railway Zone/Division.
It is operated by North East Frontier Railway zone.
Earlier Train no. 15905 & 15906/Kanyakumari-Dibrugarh Vivek Express used to be longest running Express Category train, However on March 2023. It was upgraded to the Superfast category and renumbered to 22503/22504,
And it's frequency increased from weekly/Biweekly to Daily Service.
So now Kanyakumari Vivek Superfast Express is the India's daily running Superfast Category and longest distance running train in Indian Railways, covering a distance of 4153 km and takes 74 hours around.
Avadh Assam Express is still an Mail/Express, India’s longest running distance daily running Mail/Express category train, it's Average Speed is slower, below 55 kmph. So Priority is less.