Very interesting article about the history of the chinese wheelbarrow:
The Chinese wheelbarrow – which was driven by human labour, beasts of burden and wind power – was of a different design than its European counterpart. By placing a large wheel in the middle of the vehicle instead of a smaller wheel in front, one could easily carry three to six times as much weight than if using a European wheelbarrow.
The one-wheeled vehicle appeared around the time the extensive Ancient Chinese road infrastructure began to disintegrate. Instead of holding on to carts, wagons and wide paved roads, the Chinese turned their focus to a much more easily maintainable network of narrow paths designed for wheelbarrows.
Link: Low-tech Magazine: How to downsize a transport network: the Chinese wheelbarrow via www.lowtechmagazine.com