Agar aisa hota to winters mai jab 12453 delayed aati hai to acc to your theory wo resch hi hoti NDLS se BSP ke liye jo ki nahi hota. Hence your theory fails. Aur jahan tak gallery ki baat hai, NR coaches badalta rehta hai. I have talked many times to the Ranchi Rajdhani staff. The train doesn't have RSA. A single rake for each diff route of 12439 / 40 / 53 / 54.