As yiu mentioned yes Narkeldanga Trip Shed always comprise of P4 & even spare P7s too.. But the irony is SDAH is normally the base stn for NJP bound trains whixh is a Diesel route, I wondr where are so much E locos used because there is very less no of North bound trains from SDAH. Even if it had that much of WDP-4s it would then still justify..Elocos are literally a waste in SDAH