I've been playing TSW since the first lockdown and have never turned any of these safety systems on, as I've thought it would be too difficult or I'd keep failing and I'd never complete a service as when I play, I don't have a lot of free time. In the last few weeks I've read manuals, watched Matts super video on German signalling from a year or so ago, and even played with the Zusi demo to get my head around these systems. I'm not perfect by a long stretch of the imagination, but wow, what a difference these systems make to playability. I used to avoid the straight A-B ICE runs and go for stopping services but the safety systems, particularly PZB really bring a whole new dimension to the game. I realise I'm preaching to the converted here, but if there's anyone who was like me and always plays with systems off, set aside and afternoon, watch Matts video and give it a go. Total game changer and the feeling of accomplishment when you finally complete a long run with no emergency braking is worth the concentration! I haven't started on American signalling yet. I don't want to confuse myself much more than I already am with the stuff I've been learning. Is American stuff vastly different? One thing I would like though would be a different button for PZB and SIFA acknowledgements on PS5. Maybe the unused Square+D pad up.
US and UK are far more simple. AWS just requires an acknowledgment before adverse signals, there are no speed checks. ATC/ACSES is worth learning, particularly on the Harlem line.
'US Rail Network' as it stands today was developed by a variety of organizations over a couple of centuries. They all had their own Operating protocols. So, to answer your question in short: Yes, it's different from UK / DE and it's very diverse among itself. Signals on Harlem Line are different from those on Sherman Hill which itself is different from the Pennsylvanian-style signaling on the horseshoe ! But if we go into details, the gist is that they're basically used for the same thing. Here is a page that'll help you. And as you said, take an afternoon ( because it's a little overwhelming at first ) but totally worth it
For actually driving you don't need to know the theory. There are plenty of infographics online showing the signal aspects for each specific railroad.
Nice one, thanks for the info and links. Once I've had a week or so more to let pzb etc get ingrained I'll start looking at these.