City dwellers needed food and drink no less than those living in the countryside and since they produced little food themselves, they depended upon the existence of a rural surplus. The output in terms of ton-miles performed during a working day by a man with a sack on his back or pushing a wheelbarrow is almost derisory compared with what is possible by a man with a horse and cart on a firm road surface. In short, the export of corn was less hazardous than the export of coal because the former was the product of an energy flow, whereas the latter was an exhaustible stock. Suppose you have a slow moving truck. I think generators running on biofuels will provide at least intermittent electricity to many rural homesteads. Canals passing through predominantly rural areas brought many benefits to farms close to the canal route by reducing the cost of lime, marl, coal, and other bulky or heavy materials, but they seldom proved profitable investments if largely dependent on rural custom, since traffic volumes were modest compared to canals linking coalfields to industrial and commercial centers.