Who can approve Railway and ROB drawings of DFCCIL, RVNL, PSUs and Zonal Railways?

The approval process for Railway and Railway Over-Bridge (ROB) drawings related to DFCCIL (Dedicated Freight Corridor Corporation of India Ltd.), RVNL (Rail Vikas Nigam Limited), PSUs (Public Sector Undertakings), and Zonal Railways typically involves several levels of authority, depending on the specific organization and the type of project.