I love this post, thank you for explaining it for us. You also might want to look up Minecraft Mania. Probably the most exciting thing about that mod is that gold blocks can be placed under the rails and act as 8x boosters. The problem is that when Minecraft updates, there is a week or so where no mods work. Please check it out:
http://forums.bukkit.org/threads/mech-minecart-mania-1-07-612.388/