For context for others, US is abnormally very low in train electrification compared to other developed countries. It's not zero though, for instance there is the Northeast Corridor which is electrified and the most used passenger train routes in the US

Here's a map of what's electrified in the US

And here's it with the rest of the rail network

Meanwhile here's what it looks like in Europe

There are now some battery-electric train options if the US wanted to use a stop gap solution to allow partial electrification to more quickly be a line without any diesel needed. Though a fully electrified line would be more ideal for the longer-term

the rail lines are already expensive and long, I can't imagine the cost of electrifying them (in thr short term)