I have a large station with a forest on one end and a sawmill on the other. Wood is piling up in the station; does any portion of it get consumed directly by the sawmill? What do I need to do to get the rest of it consumed as well (preferably by the same sawmill)?
This station is exactly like a passenger station that both generates and accepts passengers:
- the wood that is being generated there needs to be taken to another station that accepts wood.
- the station will accept wood from other sources, but never from itself.
None of the cargo is "absorbed" by the local sawmill - you will need to transport all of it away, and if you want that local sawmill to generate goods you will need to transport wood in from another source.
it won't be consumed, a station can either be a source or consumer, but not both. What you have to do is create a separate station, preferably that only covers the sawmill, and transfer between those two.
If you can't, you'll have to specify which station to load/unload at as shown in this answer
My favorite trick in this situation (and others) is a shuttle. Build a small loop of road disjoint from any other roads; put a depot on it and add a truck stop or two.
If, say, the station covers both a Forest and a Sawmill then I want to move Wood. Two drive-through stops can handle about four trucks. Each truck is ordered just to Unload and take cargo at the one station. This will work if there's just a single order in the list but you may get messages complaining there aren't enough orders. To eliminate these, duplicate the station order and alternate station stops with Maintain at nearest depot orders.
A similar trick works when a station supplies cargo but I can't manage to run trains to it regularly enough; I want to pump up the station rating somehow. For this, the order is Transfer and wait for any full load. This works even if, as in the previous case, the cargo is accepted at the producing station: transferred cargo is not accepted; it's not consumed and waits for the next vehicle out.
Finally, a related gimmick works to ration out scarce Engineering Supplies if you are playing NARS. Have your train transfer a load and have one small truck make the loop. In this case, you want to buy a slow truck and perhaps even order it, between station stops, to Go to depot (Always go).
Shuttles aren't usually profitable but you can absorb the small cost; and they solve many issues like these.