Chunks and Redstone
Solution 1:
I assume that you're in 1.14.2. If that's the case, then your only option is to put the spawn chunks into the middle of the tracks and hope that they reach far enough:
/setworldspawn <coordinates>
The reason for this is that chunk loading outside of spawn chunks is completely broken in 1.14.x, including /forceload. I don't know why this would affect your redstone line, but maybe there's also a bug with that, it's hard to test while there are still bigger bugs.
Here are some more reasons why I recommend staying in 1.12.2 for now.