BPL shatabdi has longest run (over 700km) and it returns to NDLS at 22:30 hrs which is too late. Hence it urgently need to reduce the running time by about 20-30 minutes which can be done by using the lighter and faster train set instead of current rake. This will enable it reach NDLS at around 22:30-22:40 hrs.
Journey distance of other shatabdies are too short and they can manage good timing with same rake.