I have been reading David Bain's Empire Express, an account of the building of the first transcontinental railroad. Part of the fun was using Google Earth to trace the course of the tracks. I started at Donner Pass in the High Sierras (where a new and longer summit tunnel seems to have replaced the original) and spent several enjoyable hours tracing the railroad west to Sacramento and east to Council Bluffs. It gave me an appreciation of the scale of the achievement that the maps in the book could never do.
Meanwhile, I'm doing my one-mile walk to college every day, mostly through woods and meadows, up and down. And as I go, I imagine laying out the tracks of a railroad -- cuttings, embankments, trestles and tunnels.
At first, I had in mind an HO-scale (1:87) railroad, the most popular model railroad scale in the US and the one I could most easily visualize twisting and curving along the path. But then, after a few days, I began to wonder just what would be the scale if my approximately one-mile walk represented the nearly 2000 miles from Council Bluffs, Iowa, to Sacramento, California.
The distance ratio is 1:2000. The gauge of the transcontinental railroad was (and is) 4 feet 8.5 inches. Which means the distance between the rails of my imaginary railroad is less than a millimeter, and a locomotive would be less than a centimeter long.
So now, as I walk, I imagine that tiny little train puffing along that thread-thin track, following my half-hour walk to school -- and forge an even greater appreciation for the monumental achievement which was the first transcontinental railroad.