You have interpreted this in a wrong way. This is not a diversion of EDFC. This is like a service lanes which are present in major cities/towns/villages in National Highways, where people of that particular place uses that lane and that lane joins the main NH after some time. Similarly, the actual EDFC will pass though it's original route via Sonnagar-Gomoh-Andal-Dankuni, these extra service lines from Hazaribagh, Deoghar will just join them at some place. For example, the track from Hazaribagh can join at Koderma or some nearby place, similarly the track from Deoghar can either join at Sitarampur or at Koderma, if Jasidih and Madhupur bypass are build by that time.