Ah, yes, no arguments with anything you've said there, just wasn't sure what obstacle to electrification itself you were seeing.

That said, it may be cheaper to just electrify it rather than deal with a unicorn in terms of equipment if we are at the point of full electrification elsewhere and still can't make a decision on the extensions. I agree it'll likely be one of the last to do anything with.

Being a low-frequency branch doesn't inherently mean it can't be electric - NJT's Gladstone Branch runs a relatively similar operation that way. (mostly single-track, often requires a transfer to a different service to get to where you likely want to go).