John,
I can't give the definitive answers but I can clarify one major point. Kyle was not the original operator, that would have been Scenic Railways.
The major reason I was told/heard that Kyle relinquished the concession was the retirement of the founder of Kyle which resulted in a mission change in Kyle operations.
There are far more authoritive people that regularly visit this page that can/will add to your question.
Thanks,
MAS