I just set up my first train and have big issuess. I have three stations: Islamabad, Karachi and Lahore.
In Karachi I want to load green and red circuits and unload at the Islamabad station. From there I want to load lubricant in barrels and blue circuits which I want to unload at the Lahore station on belts for further processing. Yes, you guessed right. It is the Chemical science MkII I want to produce

But it is not working as intended. It unloads as planned in Islamabad but not unloading at Lahore station. The train just stops. Everything is in place. Even filter inserters. But no luck.
I dont understand the "AND" and "OR" values.
Is it possible to just load a certain quantity istead of items? I need more green circuits than red but 200 get loaded everytime.
Help!