I said it before.
It's all depend on Time table.. ex. Brahmaputra Mail(mail express) departs from Old Delhi...
It halts 3-4 stops between Delhi and Kanpur....
It is followed closely by Bhrigu(Superfast Train) and stop at Aligarh Junction......
But...
more... Brahmaputra mail trolls bhrigu till Prayagraj because its time table is synchronized accordingly....
And if any train is running delay...
Zone treats accordingly...