So I have been trying to think of a way to zip from the bottom of my mine to the top quickly. I figured that a magnetizer would be perfect, however, my mine goes down almost 60 blocks, and the magnetizer can only do 20. I then found out that you can place one in the middle of the line of iron fences and it will server both 20 up and 20 down, but when trying to ride it up I get stuck on the magnetizer in the middle of the run. Is there any way around this? or is this a flaw in the magnetizer that has no fix as of now? Any ideas would be appreciated. 
