The pecking orderPossibly BHPBIO, RIO, FMGThe first two really...

The pecking order
Possibly
BHPBIO, RIO, FMG
The first two really did not want FMG and I think they thought FMG would fall over, which it did not.
None of them want anybody else. I cant see FMG wanting to help FMS unless they jointly develop adjoining deposits and share both rail and infrastructure costs. Any joint agreement would have clauses limiting FMS's growth, however a joint agreement with other juniors would not limit growth.
Sooner or later government action will force combining rail networks it's just logical. Try to understand those rail networks are built on commonwealth or state land and are heavily subsidised by taxation breaks.
We are back into the shenanigans of the 1800s industrial revolution times.
What gets me, is socialist governments seem to be more reluctant to help the underdog than liberal governments. For all of you out there who believe in socialism which I don't, ponder this thought. Socialists only worry about fair play before they get elected and then plunder the system.