After making my starter base, I was working on a train system using train limits, circuits, and bidirectional 3-8-3 trains. I realized the scale was too large for me, and I wanted something smaller and simpler. I had also messed up the fueling system, and wanted to redesign it.
I nuked the old system (literally and figuratively), and I want to switch to unidirectional 1-4 trains, but still using train limits and circuits to calculate the limits. I also want a single fueling (maybe adding multiple as the factory grows) station that is visited by all trains.
Any suggestions for planning or designing something like this? The only mega base I have ever made was a spaghetti mess and I'm trying to be a bit more organized in the creation of this one (the initial goal is 2.7k spm)
Hmmm, it’ll be hard to do what you want, most notably the single refuelling station, with just vanilla trains.
I used to have refuelling on every stop in a base (main base, big outposts). Then the trains would go between them and mining outposts for example. I’d name all similar stations the same so that it’ll go to the nearest activated station. (Deactivate them when demand has been met). That worked fine for me.
Nowadays, however, I use LTN to achieve something very similar to what you have. Instead of trains waiting at the iron smeltery waiting to be dispatched, they now wait in the depot and can go anywhere as long as the wagon type matches the cargo. Gave me the benefit of centralised refuelling in the depot and fewer active trains at any given time. Really worth looking into LTN if trains are your thing. I promise it’s not as complicated as it may look at first. :)
There is straightforward vanilla friendly mod from one of the Factorio developers that handles train refuelling and train depots, the Train Control Signals (you need to use vanilla station limit feature). Also aside of the already mentioned LTN you could try Project CyberSyn and/or TSM.
I did a LTN light playthrough. Meaning that I had LTN installed, but only used it to keep stations logistic storage topped up with stuff required to build the defenses. For all the other transportation needs like moving items from factory to factory I used plain old vanilla train logic.
Maybe you could use LTN to keep fuel at outposts and refill the trains there?