ALD-NDLS is 9:30 hrs journey and extension to JU means further 10-11 hrs i.e. 20 hrs journey which is not possible. At the most the train can be extended by 300-350kms so that same rake can be used to give overnight journey between Allahabad and Delhi which exactly is the prime purpose of this train.
Possible extensions are Jaipur, Chandigarh, Ludhiana, Dehradun
ALD (21:00 )NDLS 6:00 6:30 --JP 11:30
JP...
more... (17:30) NDLS (22:30 23:00) ALD 8:30