So in short, electric freight trains are not 'disruptive'; they don't compete with diesel freight trains unless you have enough political pressure to prioritize passenger trains above diesel freight trains.
That is according to the railroad. There are others who question the math, which is a valid thing to do, though I don't know who is right. In any case it is possible to wire all US freight, but so far nobody has done it.
So far, it is not.
And India runs electric double-stack container trains, but of course it would be an enormous upgrade project to convert to this -- tunnels and bridges more than the wires: https://www.youtube.com/watch?v=yNq8lP6cfL4
It saves a small but noticeable amount of fuel.
https://www.nrel.gov/transportation/fleettest-platooning.htm...