In Brass: Birmingham, what are the differences in the consumption and transportation network requirements for coal and beer during the Canal Era and the Railway Era?

When starting the heavy strategy game "Brass: Birmingham," people often get confused about the network connectivity for resource consumption: When building or flipping industry tiles, what kind of connected network do coal, iron, and beer each require? Why can iron be used across the entire map, while coal must be connected to a coal mine or merchant route, and what is the difference in transportation between self-produced beer and market beer?