Yes, I'm sorry that I got carried away with my latest toy I developed. I made a supply system whose loading station (re)fills a train with a selection of items, the items being configured by as many constant combinators as necessary. And the corresponding unloading station that will unload as many items as configured in the constant combinators of that station. It can be used to simply restock an outpost with ammo and repair kits, but it can at the same time also build a whole outpost from a put down blueprint, as long as the player builds the unloading chests, circuit and one roboport. This is why I built it in the first place: I was tired to build an outpost with not having enough items in my inventory to construct it fully.
It even loads the empty roboport to initiate robot operations and brings back trash to the loading station It consists of 1 chest and 3 combinators per wagon that in essence only do adding/substracting/filtering/setting filter+stack size for the filtering stack inserter, but it's by far the most complex thing I ever did because of the wiring. The supply unloading station is intended to be located on the other side of the track of a mining post loading station, so that adds complexity as well to not mix the ore with the supply stuff.