Answer:
I grow up while growing down
I can be hairy and itchy all over. I can be the scariest thing you have ever seen. I stand in the middle of nowhere, hanging on a stick. What am I?
I come with a train and go with a train and the train doesn't need me but can't go without me.
When it comes to me you go on red and stop on green.
I sit in a corner while travelling around the world.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.