Rajdhani express are premium category trains by the Indian Railways that redefines luxury travelling in India. It is a fully air-conditioned train which connects country capital (Delhi) with state capitals. That is why they are called 'Rajdhani' which translates to 'Capital' in English. These train runs at very high speed and therefore it usually takes least time to reach destination compared to other trains on the same route. Mumbai rajdhani is the fastest rajdhani train which attains a maximum speed of 140 kmph on some stretch. Rajdhani Express offers catering facilities inside the train the fare of which is included in ticket fare. Rajdhani trains have 3 classes - First AC (1A), AC II-tier (2A) and AC III-tier (3A) only and they are coupled with LHB coaches that have higher safety features. The ticket fare for Rajdhani is maximum amongst all trains on the same route and has dynamic fare (Flexi Fare) system. Waitlisted passengers are strictly not allowed inside this train. Rajdhani train coaches are usually painted in red with a grey colored strip outside. 2 rajdhani trains run from New Jalpaiguri to Diphu - New Delhi Dibrugarh Town Rajdhani Express (12424) and New Delhi Dibrugarh Rajdhani Express (Via Samastipur) (20504).
New Jalpaiguri to Diphu New Delhi Dibrugarh Town Rajdhani Express (12424) departs from New Jalpaiguri station (NJP) at and arrives Diphu station (DPU) at . This train has 7 stoppages. New Jalpaiguri to Diphu rajdhani fare is Rs.2905 in First AC, Rs.1370 in Third AC and Rs.1815 in Second AC for this train which includes meal charges also. Dibrugarh Rajdhani is Rajdhani train connecting New Delhi with Dibrugarh Town. Dibrugarh is the only non-capital city in India to have Rajdhani train originating and terminating in it on a daily basis. There are 3 pairs of Rajdhani train connecting New Delhi with Dibrugarh and Guwahati. Dibrugarh Rajdhani is said to be the slowest Rajdhani amongst all the Rajdhani trains. Its average running speed is only 65 kmph.
New Jalpaiguri to Diphu New Delhi Dibrugarh Rajdhani Express (Via Samastipur) (20504) departs from New Jalpaiguri station (NJP) at and arrives Diphu station (DPU) at . This train has 8 stoppages. New Jalpaiguri to Diphu rajdhani fare is Rs.2850 in First AC, Rs.1335 in Third AC and Rs.1785 in Second AC for this train which includes meal charges also.