Found this from the IRFCA Message Archives. Could find only the schedule up to Varanasi for the Patna Raj: ( Credits to Mani Vijay Sir).
Mani Vijay Sir probably has the Full TT.
dep. N.Delhi 17.00
arr. VNS 3.55; (Varanasi)
dep....
more... VNS 23.00
arr. N.Delhi 10.00
And seems to have been diverted via the current route sometime in January, 1999.