Copper Rails and more...

Minecarts are a pretty good concept but ice boating leaved them behind, i have some ideas to make them a better form of trasportation!

•  Copper Rails: Change the gold rails to make the minecart speed up to 24 blocks per second and add copper rails a cheaper and slower option that make minecraft speed 8 block per second 
• Cheaper Rails: The recipe for rails should give 32 rails insted of 16 
• Leashable Minecarts: Give the ability for minecarts to be leashed together
• Blast Furnace Minecart: Works like the Furnace minecart exept that it uses 3 times the fuel and travels 48 blocks per second
• I belive these changes will improve minecarts to be closer to ice boats but not be better than them.