I would love more than one booster speed. What I mean is imagine that you have a Redstone block, and you can set it to 1.5x en the config, but you can also config a lapis block that give you 2x speed and a gold block for 4x speed. Also, I don't quite like when you are going up in a slope it should launch you from the speed, not just fall backwards. idk if any of these changes are possible, but I would love to see them.
Works perfectly. We have some longer minecart tunnels on our server and these rails make traversing them take a lot less time, while still keeping a survival element.