With SA normal trains feel a bit lackluster when compared to just belting things (240items/s with stacked turbo belt). Trains suffer as everything got faster or better with quality except train wagons.
Any chance for Quality implementation?

Edit: found the (I think new) setting for more slots 5min after posting......but still think quality progression would be neat as optional content

There are also mods that make trains affected by quality - eg. "more quality uses" (internally uses new entities, but improves speed/acceleration/capacity of trains and even capacity of storage tanks) or "wagon quality size" (uses vanilla features, but can only improve wagon capacity with quality, and not any other stats).