Diesel Locomotive can't be Off like Present Diesel locos but Electric One can be Easily Switch Off or on.
As we know Diesel Engine continuously runs
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...
more... Powerful Loco of IR
Ya In Diesel Lines It will act as Simple WDP4D