It occurred to me as I was watching this video of an incredible water 'slide' built in SMP by Chilldy06 and Cipher004 that I realized I'd been wasting my time messing around with tracks and minecarts and boosters. Let's face it. Minecarts suck. They suck badly. Unless you use glitches in the game to make them work, they're slow and ungainly and they're stumped by hills almost entirely. Even with a powered minecart, it's far too easy to put the coal in the wrong way and then end up chasing your cart all over the map until it runs out of coal.