I don't think railways will allot a spare in the present scenario till the production increases. It should be for some new route. What I heard is introduction is delayed due to works in BZA division. Post that they may start a service.
I also think IR can run some routes with tri weekly or 4 days a week. Not seen any VB in that frequency. If VSKP VB can be run like that a proper RSA can be planned to cover up any unforeseen delays of VSKP-SC VB