The US uses a different system. It shouldn't be that surprising. :|
What you forgot to add there is that the US is one of only two out of the world's two hundred countries to still use miles instead of kilometers (the other being the UK, in case you're wondering). When you put it like that, it is pretty surprising.
Note the starting coordinates X and Z (Y is only used for height).
Place 1000 rails in either X or Z direction, preferably on a level surface. Be sure to add a Powered Rail every 32 blocks for maximum speed, or every 64 blocks if you're running on a low budget (keep in mind that the speed will not be perfect with the latter alternative).
Make sure to place a couple of extra rails to avoid failing the achievement after 998 rails (or something similar).
I thought they were teaching the basics of metric system at school, as it includes most of SI units, and is used by 98% of the world or so.[/quote]
As I go to a public school, they would rather people concentrate on standardized tests, and the last time I checked, there are basically no problems on metric units, except for one where they tell you to use a centimeter side of a ruler, and that's basically to just get people to follow directions.