I think there would be many reasons not build a rail line but...

No, there is no inherit problems with Atlantic' plant atm as they have already fixed all problems and bought a lot new equipment. The problems were not due to the mechanical processing issues, they were because; (as explained on my first post, that was mentioned in The West  Australian article)

Windimurra’s historical production problems was because of poor recovery rates, resulting in lower than expected ore grades and low high-grade ore volumes, resulting to the higher operating costs.

I think there would be many reasons not build a rail line but relocating the plant would be better in the long run;

1) Building a rail line might be even dearer than relocating cost. 
2) Maintenance of a rail line is expensive and would be an ongoing cost.
3) If AVL joins the party there the resource in Gabanintha would be the world's largest. No one could compete at any V price.

Therefore it's better to have the plant in Gabanintha. no doubt about it. 

I hope the managements of TMT and Atlantic would see this opportunity and start the production of this world class project. 

At least, the market cap of TMT is so low now; only $20m. Atlantic can buy out TNT easily by paying say $60m now, by a friendly or hostile takeover I mean.  

Atlantic spends so much on that plant with no chance of finding enough high-grade ore to start the production without any problem. I don't understand their business mentality why they are insisting the high-grade ore and spend more money on an nonexist thing. 

It is also thought that SFM has high grade ore which is 80km far from Windimurra. If they drill and find high-grade ore Atlantic buy out SFM's deposit. But SFM insist not to drill their deposit. I also asked those questions on SFM thread and SFM management.

I am working on this issue for long time. I can see the problems and solutions but I can't see any action from the parties.  

Something is going to happen in Windimurra and Gabanintha one day, and we will be all surprised IMO.