How about this very potentious route....taking the Bogibeel bridge....bypassing the mainline of Tinsukia Division and Guwahati in the process....taking lesser time....
The train goes via Tinsukia, Dibrugarh, Harmuti, North Lakhimpur, Rangapara North, Rangiya and New Bongaigaon....
The train departs daily from Ledo at 05:00 hrs. and arrives at Alipurduar at 20:00 hrs.