Oh wow, I'm very excited about this. The post author wrote the absolutely incredible Space Exploration mod for Factorio, pitching itself as a "100+" hour expansion, realistically closer to 1000 hours for an average player. Space Exploration has its quirks, but is fundamentally an absolutely outstanding puzzle game, among the best ever made. One of the most delightful things about Factorio for coders is that the game…
I wouldn't put trains and smooth in a single sentence. The signals required a lot of patience to learn and I'm not entirely sure I still understand them. They are by far one of the most painful parts of factorio for me.
I had over 500 hours in Factorio before I felt comfortable with signalling. I got so frusturated with it originally I just ignored it as best I could.
But the "chain in, rail out" thing as others are mentioning really is the key. It's not always as perfectly simple as that, but it's a very good starting point.
You break everything up into blocks ... if you place a chain signal right before an intersection and a rail signal on the way out, you'll be there for most situations.
Most.
My most complex map has about 50 trains running and all intersecting each other and so far, everything is running smoothly on that one. No trains slamming into each other and everything running efficiently as far as I can tell. Almost all of it is just that "chain in, rail out" thing.