Since 1.14, minecarts derail visually (currently playing on 1.17). If you have many curves it may be that you can still enter a minecart but it's visually derailed. It's then in blocks and does not drives on the rail but still uses it. I tried building railway stations 1.14 - 1.17 and it never worked because after a few minutes they're derailing and not "using" the rails. idk how to explain this better but it's just sad to not be able to build with minecarts in this way.
Xge
Since 1.14, minecarts derail visually (currently playing on 1.17). If you have many curves it may be that you can still enter a minecart but it's visually derailed. It's then in blocks and does not drives on the rail but still uses it. I tried building railway stations 1.14 - 1.17 and it never worked because after a few minutes they're derailing and not "using" the rails. idk how to explain this better but it's just sad to not be able to build with minecarts in this way.