Well, somehow it IS possible to gather all that material with our trains bringing stuff every two hours.
Although I do have the feeling the trains always carry the items I have most of. Is it like that for you as well?
ah I see, you mean the building materials. Yes, they come in, but slowly - so slow that they have to compete with barn materials now again.
But I try to even them out - not always the same they bring "too much"; for a while it was glass; at the moment, slabs are coming much faster than the other 2.
The only thing I keep getting really MUCH too much of are shovels.
So, for the trains I can not confirm your impression really. But in the market, I often have the impression, the next wave brings what I JUST have planted.
In any case, re. zoo material, whether it's hinges or screwdrivers or bricks or whatever next I do NOT get, doesn't matter.
It's simply slow-moving and boring.