As we know Diesel,Engine continuously running
When It Will run in Electric Section Its Power will be
4500 Hp + 4500 Hp Becomes = 9000 Hp Loco More Powerful than WDG5's 5500 Hp n WAP7's 6000 Hp n WAG9's 6850 Hp Most Powerful Loco of IR
Ya In Diesel Lines It will act as Simple WDP4D