Kumar was General Manager of Western Railway before becoming the Member (Mechanical) in the Railway Board.
The post was lying vacant since Alok Johri, former Member (Mechanical), retired on November 30.
Railway Minister Suresh Prabhu has made concerted efforts to fill all top posts in the Board. Recently the posts of Chairman Railway Board, Member (Staff) and Member (Electrical) along with eight General Managers were filled up on December 31.