well if the track is that bad how can the stone train even run on it with all that tonnage?
Well at the risk of being pummelled for being hard on you Heath, I have to ask, are you really that thick Heath.
As Ian has stated, the track is in a very bad condition and I'll put it in a context that you may understand (do you even understand what 'context' means? look it up).
Let's assume that the railway line is actually a roadway:-
If it was a really good bitumen road, passenger buses and freight trucks - even a road train could travel on it at high speed very safely, and people would get from A to B quickly and be happy.
If it was a rough bitumen road the buses and trucks would have to travel slower to be safe but the journey would be longer, people would not be happy, if the bus tried to go too fast the passengers would have a rough uncomfortable ride and the bus may even have an accident, it doesn't matter about the freight trucks as the stone they are carrying doesn't get hurt, they just take a lot longer and slower so that the truck doesn't have an accident.
Can you imagine what the road would be like if nobody did anything to repair it for 20+ years (I actually think it would be far more than this), all the bitumen would be smashed up, there would be pot holes everywhere, when it rained the road would be all slushy and muddy, when the trucks went over it they would make it worse, and they would have to travel very slow so they didn't have an accident.
The buses couldn't go on it, even travelling very slow the passengers would have a very uncomfortable ride - if they tried to have a drink it would get spilled everywhere, they would have to travel so slow that nobody would want to ride on it, they would drive theie own car.
The other problem is a big boss somewhere that makes the rules about who can travel on the road will say it is OK for the big trucks to keep using the road because they only go really slow and that doesn't matter because nobody will get hurt, but they will say the road is too rough for a passenger bus because the chance that the bus will have an accident or run off the road is too great, he has to think of the safety of the people that travel on the bus as well.
Another big boss who owns the roadway isn't going to spend money on it to fix it up because he doesn't have to, the only people to use it is the truck people and it is fine for them because they can go slow, besides, that truck might not have job soon anyway. This big boss would have to spend a huge amount of money on the road for the bus to be able to drive safely on the road and be able to get the passengers to somewhere in a reasonable time, now the problem is that he has got a good memory and can remember that the buses tried to carry passengers on this road one time long ago, but the bus driver couldn't get enough people to travel on his bus, he couldn't make enough money so the big boss had to pay for some of his huge expenses to carry only a few people every now and then.
That Heath is how it is, do you understand now, if not, may I suggest that you take yourself somewhere else and seek the answer you desire.