Given electrification of railroads has been going on for decades...

The U.S. is woefully behindl.

38% of the British rail network is electrified (not counting light rail systems).

I'm seeing it listed as a goal to electrify "15 to 30 percent" of U.S. railroads, with the argument that that's the best we can do. Yet in the 1930s we were the leader.

The American Association of Railroads is arguing hard against electrification. It's true that there are some legitimate arguments.

These include the length of many routes and the big one is that the U.S. tends to run fewer, heavier trains, and until very recently there wasn't really an off the shelf option for electrification.

Because of this only a few passenger lines are electrified.

One thing to consider is that the technology exists, literally exists and has been used (I've not just seen it, I've ridden it) to create trains that run on electric where caternaries are present and then switch to diesel where they are not. This kind of partial electrification wouldn't be ideal, but it might be more feasible in remote areas or situations...for example, two passenger trains a day run to Williamsburg VA on a single line, I don't know how many freight trains. Electrifying that line might well not be economically feasible, but electrifying down to Richmond would, and then the engines switch to diesel for the last leg. This would be an interim measure while we develop full-battery locomotives that don't require overhead wires. Sorry for the long response, but electrification is old, not new ;).