Copper Rails

Copper Rails as a substitute for the current iron rails, though levels of oxidation would cause it to slow down. Iron rails would be buffed to allow a greater maximum speed (and potentially new minecarts with higher maximums). 

To offset the increasing (and already existing) cost of honeycomb to wax (which we shouldn't need to farm in order to build in large amounts), a "wax sponge" could be a usable item crafted with 1 sponge and 8 copper ingots. After a number of uses it would turn into a normal sponge but would allow more efficient waxing and motivate players to find an ocean monument.