I don't really understand your viewpoints. How is Railroad "too late to make a difference"? It's not that late a tech, nor is it a bad tech. The production bonus for railroad connections is +25%, and I often have Workers loafing about building redundant Farms or Trading Posts. They can rip around retrofitting all my roads to rail and giving me a big production boost.
For a science victory, railroad isn't needed until you're rushing those last few techs to get the spaceship going. It's one of the techs I normally knock out with my 'Great Scientist rush' to head up to Satellites and build the Hubble Space Telescope, which is normally the very last thing I build before spaceship parts, leaving no room for Neuschwanstein.
For a culture victory, it's pretty much the same thing, because I'd be heading towards internet tech, so the complete bottom half of the tech tree gets neglected, I normally don't have anything past Dynamite down there, and I only have that for artillery or else I'd stop at Fertiliser. Neuschwanstein would be useful for the culture I suppose, but it would slow down my win by at least 10 turns to get Railroad when instead I'd rather just get to Internet.
For diplomatic victory, Neuschwanstein could be built if city states wanted it, but other than that I just wouldn't bother building it because of all the bonuses I would be getting from city states at that point in the game. Everything that Neuschwanstein offers, city states offer more of it - It would become redundant and a waste of turns that I could instead spend even just on straight up money to keep those city states as my allies.
For domination victory, I can see Neuschwanstein being very useful to keep that happiness up, but at that point in the game, I'd have maybe one or two civs left to knock out, so why bother when I can just build a couple more units and steam roll my way to victory?
As for time victory, has anyone ever played to this point...
The Castles don't have to be pre-existing: knock Walls and a Castle out in a couple turns per city for a sick Happiness, Culture, and Gold boost. I almost never have castles either, but after I get Neuschwanstein it's like freaking Disneyland in my empire: castles EVERYWHERE for the fun of it.
I could do, but that would waste even more hammers. Honestly, I like to win as quickly as I possibly can, that's how I play, that's what I find fun, and as much as I love the idea of Neuschwanstein, the bonuses are really huge compared to most other wonders, especially at that point in the game, it's just in the wrong tech to be of any use for quick victory strategies and so I find it difficult to justify spending the extra hammers and turns on it for what would be a very shortlived wonder. Let's put it this way - by the time I research railroad, I'm normally around 25 - 30 turns away from winning. Add to this the time it takes to build the wonder, that leaves me with a maximum of maybe 15 - 18 turns with Neuschwanstein. Not worth it for me.
I hope that explains it well enough so it doesn't seem like I was just hating on it for no reason
I can see why some people would like it, but it's just not for me.