Ive spotted several issues, but lets start with the basics. A section of railway between two signals is called a block and only one train can be in a block and as long as a section is occupied no other train is allowed to enter.

Another function of signals is determining the drive direction of the ...

Okay, that makes sense. I'll work with some sandbox to figure this out more.
Thanks for the help.

fiddled around, found a few errors that still shouldn't affect the train path so I'm still looking for a solution.

PLEASE HELP

P.S.
Sorry, my first playthrough...

I have had so much trouble with trains and am slowly getting the hang of it. I have watched videos and read tutorials. I have two separate train loops. One, the one on the left, works fine. My longer and train loop on the right has some trouble. It may be because I made a loop at the bottom instead ...