Rail seems like it would be a win for someone who was mobility impaired (wheelchair, old, morbidly obese, etc.). The only other viable option would be a specially outfitted car or bus.

The times I've taken Amtrak (mainly for amusement value; Seattle-SFO and SFO-DEN), it was mainly old people (many of diminished mobility), some religious groups (mormons? menonites?), and foreign tourists. And mostly empty seats.