That doesn't work, maybe you should read the description of the Achievement, before you share your "Genius Ideas" with the world.It isn't 1000km traveled it is end up 1000km from where you started, by doing that method you end up 2 blocks away.
It's VERY hard to get this achievement. i thought it was easy, by just going around in a circle, yet, it did not give me my achievement, but now i do have it, by spending the rest of my minecraft life gathering resources for powered rails.
Once i thought i had enough, i laid them from point a, to point b, and did not get my achievement. I needed a longer rail. So, to my conclusion, you need 15 stacks of rails. (and if you want a easy rail) powered ones.
Me and Binarycon played for 1 day and got this achievement:
for the normal rail: just mine up 6 64's of iron & make 64 sticks - makes 1024 track.
and 54 gold, 9 sticks & 9 redstone dust for boosters plus some redstone torches to power the boosters.
We just went in a straight line - digging through mountains to prevent going uphill often.