It looks like your calculations are giving you square miles of track. If a track is 1/1000 of a mile wide (1.6 meters? sure, close enough, judging by the height of a damsel in distress), you’d have 2.5 million linear miles from your first estimate, and 100 million linear miles from your second.
Comment on q1:
It looks like your calculations are giving you square miles of track. If a track is 1/1000 of a mile wide (1.6 meters? sure, close enough, judging by the height of a damsel in distress), you’d have 2.5 million linear miles from your first estimate, and 100 million linear miles from your second.
That’s a great catch, thanks! With that correction as a final step, I feel much better about my initial estimate!