Answer:
In a tunnel of darkness lies a beast or iron. It can only attack when pulled back. What is it?
A trail, a union, together tied. Come across me and you will find you cannot change the course I'm on. Without me you cannot travel on. What am I?
I can only be played on a windy day. What am I?
Without a bridle, or a saddle, across a thing I ride a-straddle. And those I ride, by help of me, though almost blind, are made to see. What am I?
I am a bow that can never be tied or broken but can disappear. What am I?
No matter how little or how much you use me, you change me every month.