To work it out why lease the asset out, versus owning it.
From QAN annual report,
"operating segments do not report borrowings as these are managed centrally (mainline)...
Further if one thinks about the depreciation these assets attract, it makes more sense for the parent to absorb the write down. A quick check of QAN annual report shows where the assets all live, it isn't in J*...Wonder what the profit would actually look like if they had to absorb depreciation?