The Farm Wagon
The Farm wagon is a step up from the farm cart as you get another two slots to place trade packs. With a Farm Wagon, you can transport five trade packs at once. Near the end of the Blue Salt Quest chain, there is a quest that gives you 50 Gilda stars to buy a farm wagon design and supplies you with most of the materials to make one.
Now at this point, you can cough up the money to buy a few archeum logs and sturdy ingots to make four strong wheels. Or you can upgrade your farm cart scroll to the chroma version and from there make a chroma Farm Wagon. You can do this in the carpentry workbench.
First, find the recipe for a Scroll: Farm Cart Chroma, where you change your farm cart to the chroma version. Next, you find the Farm Wagon Chroma which does not require wheels. This is rather odd and might be rectified in later updates, but since the farm wagon quest states that you should have all the materials to make a chroma farm wagon I assume that this is the correct version. Just be aware that this might be a problem for further updates on the farm wagon into a farm hauler, but it shouldn’t be.
Now, if you used the Gilda for something else or sold the materials from that quest you can see the precise material requirements in your folio (press O) by searching for Farm Wagon.