As you can see, I have excavated this naturally generated railway, and will continue to do so until the rectangle is empty except for the railway.
As may be harder to see, there are actually two Plantera Bulbs in this screenshot – one is on the left halfway up (or down, depending on how you view life), and the other is in the bottom right. I am hoping to find some way to use the railway as an arena to fight Plantera.
As is easy to see, but you may not have noticed, the bottom of the Temple is on the top of this screenshot (which is the only reason the arena won't extend higher).
Hence, I refer to this specific railway as the 'Jungle Express'. If you want the seed (with the knowledge that Plantera Bulbs don't spawn related to the seed), ask me.
Side note: If you're wondering why I used the 'Build' flair even though this is all natural, it's because I plan to 'build' an arena here, and no other flairs fit any better.
by Extension_North_3711