This is an 'underground' safe minecart track, just not creeper safe, but they shouldn't be track spawning anyway since that's redstone. They are not likely to spawn on top, that's got glowstone.
Pasting this results in a track with glass housing forming to the east starting 1 block from user standing on track level.
It's about 1000 blocks long maybe.
Good for seeing what's underground, and keeping those pesky animals off your track during rides.