Never played krastorio or SE, but is there a reason why your trains are that short ? I usually try to have a t leas 6-8 wagons in the original game, is there some super wagon there or there is so few items built that you can't wait for a full train to load ?
I also started with 1-4 trains. Switched everything to 1-1 a little bit before unlocking the space elevator. For me it was because trying to figure out city blocks with massive input resources accommodating 1-4 trains was stupid. For instance, I've got multiple blocks that have 7-9 inputs into them. I can cram them into a feeder city block to the production one really well. Trying to fit 1-4 trains though? Yeah, not going to happen.
I also do still end up with quite a few traffic jams that are a giant pain to clear out. Adding even longer trains would make that a nightmare.
For instance, this is what my feeder blocks for my space sciences look like.
Fluids:
Materials:
I've got one of the fluid blocks for each of the 5 sciences (material, energy, astronomic, biologic, deep space), and 3 material blocks to truck in everything I need, which is then transported by robots. There are also hybrid ones that I have for making the space fluids that truck in materials and fluids from Nauvis.
Compartmentalizing everything and using 1-1 trains really made everything easier. Like with iron plates, I just have a single block with the bottom half being train stations (ore in, pyroflux in, plates out), and the top being the processing part. Bigger trains mean I need either much larger city blocks, or using two blocks for one resource. And 4k iron plates lasts a long time pretty much everywhere. And if it doesn't, well, I've got like 30 1-1 trains so fuck it.