railroad tracks

The earth is mounded, built up into a ridge, into which massive wooden beams--or ties--are placed at intervals of a couple feet. The two metal rails on which the train's slotted wheels ride are run perfectly parallel, and driven into the wooden beams with steel spikes the size of bananas. Ground rock, usually limestone, is spread onto the sides of the ridge and amidst the ties to combat erosion.

Get closer: railroad tracks criss-cross the countryside. On a hot July day, one can smell the black, oily sealant in the ties, the faint acrid odor of rusty old spikes that have been ripped loose and replaced. A railroad flanked by fields or forest becomes an insect freeway as wasps and dragonflies zip back and forth across the baking heat. The railroad tracks are a debris field, sometimes--little pieces of cargo come loose from the trains and fall, plastic binding strips with "Charleston, VA" stamped onto them, chunks of coal, or even hobo's rags, unidentifiable pieces of cloth and sack.

Walking along railroad tracks, I have seen the shadows of red-tailed hawks glide over me. Sometimes massive steel skeletons flank the tracks, draping electric lines overhead that sizzle and hum and buzz like cicadas. And then you look, ahead and behind you, often, for that single shining headlight that glows brightly even at midday.

That's when you get off the railroad tracks, and make way for their true masters.

on certain bitter winter mornings
and soft summer evenings

twice a day
as long as the engines run
In my absence, may my dreams reverberate the same

A few historical tidbits about railroad tracks:

When railroads started being built in the United States they used up massive amounts of lumber, partly because of the necessity for railroad ties, but mostly because these ties wore out extremely quickly - they needed to be replaced every five years. Something needed to be done; at that rate the entire North American continent would have been completely deforested by the beginning of the 20th century.

Coincidentally, around this time British engineers were trying desperately to get rid of coal tar, a byproduct left by burning coal for fuel. The stuff was piling up and nobody had the faintest idea of what to do with it. Some intrepid soul solved both problems at once by coating railroad ties in the stuff, increasing their usable life from five years to thirty by locking out moisture. Close shave, that.

Nowadays, though wooden ties are still predominantly in use, some interesting steps have been taken to further decrease the amount of lumber necessary. Some railroads (particularly subways because they run at much lower speeds than commuter trains) run with wood under each rail and none in the middle, decreasing the wood necessary by a third as well as allowing for water drainage down a canal located under and between the rails. Also, many higher speed commuter trains (like the Northeast Corridor AMTRAK lines which share their tracks with New Jersey Transit trains) are slowly replacing their ties as they wear out with a special kind of concrete that allows for the same standards of flexibility and rigidity as wood without killing off hundreds of trees to do so.

When I remember where I learned this stuff, I'll be sure to cite it.
The historical part came from James Burke's Connections series of books;
the source of the rest I've temporarily forgotten.