A circuit based logistic train/station to provide supply to multiple connected areas, by fulfilling orders. Can be anything that you put into the train e.g. Coal, Rocketfuel, Repairkits, Ammo ...
TL;DR
As with Version 0.17 trains are also part of the blueprint it is ready to use, just configure the cargo for the supply you will need. If you don't have robots yet, replace the logistic chests with normal chest and work with belts instead. The train shedule is just running between Load and Drop after inactive time. You can place multiple drop stations with the same name, as the station will go offline as long as the order is fullfiled.
How Dose that work?
The drop station has a constant combinator where you configure what you will need. The station is disabled as long as everything in that order is at least 20% available in the conected chests. If something drops below that threshold the station is enabled and the train will start moving. Make sure the cargowagon of your train got enough items in there to fullfill the order in one trip, because after reaching the station and adding supplies to the system the station will go offline again above 20%, but you clearly want 100% filled up. The train will return after it is inactive for 5s, so even if the station is offline it will stay as long as the inserters are working. The Drop station won't go offline if you request something that issn't in the train at all, so be aware of what you put in the train and what you can request.