Cotton wagons

Hi, everyone!

What are "cotton wagons"? I have no clue what could it be. I found it in an extract from "A Rose for emily" by William Faulkner. It goes like this:

" But garages and cotton gins had encroached and obliterated even the august names of that neighborhood; only Miss Emily's house was left, lifting its stubborn and coquettish decay above the cotton wagons and the gasoline pumps-an eyesore among eyesores."

Thanks in advance!