The big issue is the power and infrastructure. The catenary cost alone would be huge, and the you need several more power plants. As a guy who used to work at a coal fired plant in CA, the state hates them. They have already made the grid so reliant on solar that the electrical dispatchers can track clouds across the sky without looking out the window by knowing which sources are actually producing at any given moment. The is not a figure of speech.
So now you need electricity. Every 4000 hp locomotive is about 3 MW. So to power locomotives you need Billions in power plant construction. And oh yeah, a whole CA sized fleet of locomotive capable of running from the wires.
I am all for protecting the environment and incremental improvements. But this is the wrong battle to choose.