This is only a suggestion for you to think about, not a "request"

Also, here's a question I came up with:
Consider the following situation. We have an industry which accepts one of those production boosting cargos, say Engineering Supplies. Its stockpile is full. Then some Eng.Supplies are used up and the stockpile is under the acceptance limit, say 190/200. Imagine a train with a rather big load of Eng.Supplies arrives now.
What will happen? (the train is set NOT to force-unload)
Will the train only unload a portion of its load that corresponds to how much the industry's stockpile can fit?
Or will it unload all of it, the surplus going to the station instead of to the industry? Or even worse, the surplus somehow vanishes?
It'd be best if the first of these three options were true. Can someone answer this for me?
Especially if the second or third option were true, I'd opt for the acceptance (or non-acceptance) "span" I suggested at the top of this post.