Err, not possible. If one assumes six hours for LKO NDLS stretch[Shatabdi takes slightly more than this], then it'll take atleast three plus hours in best case scenario between LKO and NDLS. Assuming the train leaves GKP at six in the morning, it'll reach NDLS AFTER three in the afternoon. Assuming an hour plus at the station and it starts even before five PM,it'll be two AM before it returns to GKP. Hence, same day journey is impossible with current infrastructure.
They could run the train initiating from NDLS/GKP at alternate days...
more... which would be a possibility.