[Ulzgoroth]

Hmm, the bit I'm actually hanging up on is the railgun armed battleship escort.

Despite my previous post you could doubtless construct a case for armored warships with railguns as offensive systems (especially if you're willing to sculpt your tech setup around that).

But aircraft carriers don't need to be escorted by heavy surface-to-surface armaments. Carrier escorts in the modern world are there to provide extra missile defense and anti-sub defense. The carrier has so much standoff superiority it's fairly unimaginable that any hostile surface unit could ever get into gun range of one.

You could, of course, weaken the carrier's strike capability (with some of the same tech choices that prop up the railgun battleship existing at all), but then we have the question of why the carrier is there. Recon and defense against ground-based aircraft are also important parts of the justification for carriers, going back to before the pacific war demonstrated their strike power. But for recon, the battleships could probably host sufficient drones just fine, and it's hard to see why ground-based air power would be effective if carrier-based isn't (now that carriers and carrier aviation are more mature concepts and much bigger than the earliest ones).

Honestly the best I'm coming up with is that the carrier is primarily a floating spaceport...