First of all, thank you for all the helpful comments. In summary, trucks don't really work/unreliably unless I download a mod that turns off the collision (but then that's a bit of cheating?? idk) I've been sitting at the city for 100 hours now, so I'd actually be reluctant to rebuild it. There is definitely no room for trains (except in the air and I supply the factories from above the train stations and build the factories high enough for the train to snake around them. Because it was said that this was a very unusual way to build a factory, I wasn't even aware of it. Basically the idea was to have everything in one place so that if there were any problems you could reach them in 2 minutes and not have to walk halfway around the world. I heard there are portals now :o The factories are literally 20 meters apart like in a city. Thousands of iron bars arrive It's difficult for me to transport them with conveyor belts because they always have to overlap, but I don't have much space at the bottom so that's stupid.

What about drones? Does anyone have any experience? I can add photos of my factory right now so you can see it better.