yeah, 13251/52. Islampur-Rajendranagar-Islampur - 63 kms in each direction Takes 2 hrs 30 minutes though. Shortest distance between origination & destination stations among all express trains.
But 06501/02 stands first as the shortest travel time between Origination & Destination stations among all express trains. 1hr 10 minutes.
16522/21 takes 1 hr 30 minutes, shortest travel time between Origination & Destination stations among all regularized express trains.