SS/Poorva gets OT by: Poorva, PRYJ HS, BABA Baidyanath Exp/HS, BBS DRNTO. Further, with no stoppage, SS dont blok way for any other train & usually cover up BT @ NDLS around at 6-6:05, if its not overtaken by anyone of the above.
Vaishali OT was frustrating, as it was RT & detained at CNB and even then it was in perfect series: to be overtaken by Poorva/HS & kept ahead of Prayagraj!! Vaishali example is the sole reason for most delay at any Section & that's non-required OT!!