Compact and UPS-friendly 1x1 loaders. Works with train cargo wagons, circuits, filters, and modded belts from Bob's, Krastorio, FactorioExtended Plus, Space Exploration, and Ultimate Belts.
The problem is Cursed Better Construction Robots. When BCR builds additional miniloaders from a single robot, it doesn't raise the correct events and this leaves the miniloader broken. This will also be a problem with many other mod entities built by BCR, such as LTN stations, but since those aren't usually built in big blocks right next to each other, you're not seeing the problem with those other mod entities.