@PRASHANT MISHRA*: Re# 136920-15
I was refering to some above blocks where it was stated as trains leaving the zone is called UP and returning back to zone is called DOWN so i gave those 2 examples of Nethravathy and Matsyagandha Express, in those case your number logic suits the most because being an SR train both trains 16345 and 12619 are called UP trains, i.e., returning back to their zone.