My views are-
1. There are many trains which rush to nearby stations for PM, like 14553/54 Himachal Express rush to NLDM from DLPC for its PM.
2. BRK is not only...
more... a small town, but also sorrounded by many small villages, from where people will come to board this train. 5 AM time is simply not practical specially for passengers traveling from some far areas to BRK. Departure at 7 AM will make situation favorable for those passengers too.