Overview

It is fascinating to me how much my interest in history helps me understand the evolution of modern networks and the inner workings of the technologies that power them. Metro networks are no exception. As I studied the evolution of the network from a relatively monolithic transport construct to a more differentiated and specialized set of technologies for performing access and transport tasks, I began to see parallels between it and of all things the development of medieval village societies. I had recently read Frances and Joseph Gies Life in a Medieval Village and Life in a Medieval Castle, and many of the things I learned while reading them were still rattling around in my head.

When formal societies were still coalescing in Europe prior to the sixth century or so the world was a forbidding, often dangerous place. People huddled together in massed groups for protection because no form of social order existed to create formal, organized protection, division of labor, or any of the other characteristics of a modern society.

As time passed, the social order evolved. The feudal castle model emerged in which people lived behind the walls of a fortress and relied on an organized militia for protection. Some people lived and worked outside the walls, but they were agricultural laborers who needed to interact with the land. The artisans and craftspeople (the more specialized laborers) lived within the castle that belonged to the landholder.

The next evolutionary stage saw the development of the medieval village in...