U need not worry about VB punctuality they wil stop all other trains enroute to ensure VB is on time. Uday exp gets late because of preceding trains in Vijaywada Vskp section right from East coast which should arrive at 2110 Chennai/Tirupati BbS/Vskp weekly trains 5 days at 2230 , another 2 set of weeklies arriving in the same time zone. Though they can let Uday at 2325 late to Vskp by 30 mins and can take VB at 2330 Uday is overtaken by VB and arrives at 2345 or even more late as it doesn't have maintainance schedule and has SM/PM on weekoffs.