Your specific problem can be solved without using a counter.

Set each train station to read train ID, and attach it to a decider combinator that outputs 1 if the ID is greater than 0. The output from the 5 decider combinators is your train count.


The problem I run into is when a train isn't in ...

Train logic problem. One of the 'When' statements need a permanent counter circuit that can take increments and decrements, and the other 'When' statement needs a permanent counter that gets reset upon outputting a value.

Problem: I have an infinite amount of trains in a lane, waiting to be ...

What I want:

IF miner's 'Expected Resource' property === Coal
&& signal on circuit network === Green

THEN
Turn off miner

Is this logic achievable without mods? Say I have 500 miners, and 100 are extracting coal as an expected resource, then when Green signal turns on, all of those 100 miners turn ...