The direction of a bus, being horizontal or vertical depends on personal preference and how one likes to work on the production that splits off it, which can almost always be expanded for greater use later on.
This can be done to reserve room for later expansion, blueprint-ghosts are a good usage for that as they don't allow the belt to be filled with non-usable items. This is especially deceiving when the item isn't moving and all belts have filled up as these belts can't carry the amount they lead one to believe they can. When one doesn't have enough production to saturate a belt (or splits it into more) then this can be called a 'fake'-bus as it can not be saturated. Whether one uses a bus is often decided before starting a map or when first building an array of furnaces.Ī bus often starts at the smelting of iron, copper and steel, and then over time and distance gains more and more different items. This is also a downside as there are more belts used and therefore more room for belt-buffer and everything is less compact. This is a good measure to combat 'spaghetti factories' as it forces someone to plan a structured layout and move everything to use items from the bus. The concept of a Main Bus is to put the most used and useful ingredients in a central spot to use for assembling machines. The main bus in use with several different items and some production
