There are very few passing trains at SC (excluding trains terminating at HYB/KCG/LPI).
The only daily trains coming from Kazipet/GNT side and going towards VKB are SBC Raj, Konark, VSKP LTT, MTM-BIDR, MGRU-KOP and Palnadu.
Of these, Palnadu, MTM-BIDR and MGRU-KOP were just extended to de-congest SC, so they cannot be made to bypass SC.
Konark and VSKP-LTT are not around in...
more... the peak hours, so making them bypass won't make much of a difference.
SBC Raj is the only other daily train left, and considering that it is intended to serve as a Rajdhani for both SBC and SC, it will not be made to bypass SC as well.
The remaining passing trains are non-daily trains, mostly weekly or bi-weekly ones, which again do not matter much.
The small number of passing trains don't contribute much to the congestion.