It means that you have to alight at Bhusaval & take/board 15017 Kashi Express (both trains rakes meet @ BSL & then it moves to GKP), don't worry the boggies of the train 15017 is attached with your pune-gkp train & they move forward, that's why a stoppage of 6 hours is allotted. check schedule of your current train in which you have the reservation. For any issues, msg right here.