Personally speaking, I consider both as the same train like we have Hwh Rajdhani via 12301/2gaya and via 12305/6 patna.
just check the similarity between 12305/6 and 22221/2 W.R.T distance, speed and time.
Besides, the patronage and priority that CST Rajdhani is as good as WR n ER Rajs in thier respective routes.
Besides, the common path mathura-nzm, I think the average...
more... speed/priority given to CR n WR rajs is same too.