Hello, I noticed that some custom trains as "SE Space Trains" or "YIR - Uranium Power Trains" lose their wagons or the rear end of the train during entering/exiting a subway tunnel. Is there any adjustment that I can make to my files to solve this?

That doesn't happen with vanilla trains? The code is not distinguishing between vanilla and mods

I just tested with the vanilla, even those get stuck when trying to exit or lose one/few wagons when passing through a tunnel.

Can you send me your savegame with your setup (without other mods)?
Are they running at high speeds?

Here's the link with a test save, the same issues as in my modded game.
https://drive.google.com/file/d/1is6KQNwvz0chsRhUtNZbYl7i5n2K9nS5/view?usp=sharing

You did not build the opposite parts of the subway

You mean the entrance/exit? Or is it an item like the underground pipe that has 2 parts together?

Yes, when you have the item in the cursor you see where you have to build them to connect

I have 4 subways entrances/exits in this save, two overground and two underground. I will look into it again, sorry.