Answer:
I am of several different kinds, but the one you pick doesn't do its job. 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.
In your fire you hear me scream creaking and whining yet I am dead before you lay me in your hearth.
Goes over all the hills and hollows, Bites hard, but never swallows.
I am an animal and a hair product
If I say "everything I tell you is a lie", am I telling you the truth or a lie?