The main-line steam locomotive

technology

The traction that made these routes possible and the traction whose limits shaped them. A steam locomotive carries its own fuel and water and consumes water fastest of all, so a steam-worked long-distance route is punctuated by water columns and coaling stages at intervals the terrain and the climate set — which is one reason a line across an arid or frozen region is far more than a matter of laying rail. Adhesion between smooth steel wheel and smooth steel rail caps the gradient it can climb, which is where the ruling gradient comes from. Every route in this Journey was surveyed for a machine that no longer runs on it: the Trans-Siberian, begun in 1891 for steam, did not finish electrifying until 2002, and the alignment it electrified was the one the steam survey chose.

A technology is not a place. Drawing it on a map would assert something about the world that no stored fact supports.