It's scheduled overtake if 18048 is supposed to arrive BBS before 17016 then overtake has to happen. Simple as that even some SF trains have scheduled overtakes over other SFs.
As a result of this ECoR goof 18048 reached 50 minutes late at HWH.
Amaravati has SF schedule on par with other SFs infact faster than some SFs in BZA HWH stretch.