The apparition of these faces in the crowd ;
Petals on a wet, black bough.
— Ezra Pound
My idea is to eventually have multiple parallel tracks, but I'm starting with one. What you need to get started is a button or lever, a powered rail and a minecart.
Then plonk down 37 regular iron rails after it (for optimal speed!), followed by another powered rail, this one permanently powered by a redstone torch:
And you're away! Traveling by minecart is much faster, and on a properly constructed track, safer, than on foot. Some engineering may be required; for instance, I had to build this bridge over my chasm:
I wrote about mob spawners in my last post, and I've now gone from never having seen a dungeon in my life to running into one every time I start digging...
But in the end, this is what you get: a quick and safe underground ride in a minecart.
As I said, digging this damned long tunnel was neither very interesting or photogenic in itself, but it's very rewarding. I have a subway system! Here's an approximation of where the line runs on my composite map, with the "stations" marked in. As you can see, I've nearly reached Epic Island!
The one at the bottom (furthest west, that is) is my underground base; the next station down is the latest tower I've built, and the last one, well, you'll see!