Diesel electric are not at all the same as an electric train network. Electric trains have a very interesting property, as they work as a grid as both producers

Diesel electric are not at all the same as an electric train network. Electric trains have a very interesting property, as they work as a grid as both producers, feeding back when they are breaking. You made a second point, that most trains are already "diesel electric", I am pointing out, that the function is very different from an electric train, and much less friendly(and less efficient) to the environment.