CMStPnP
I think one person in the cab is insane, even with PTC. I would think you need the second pair of eyes as a check. Also an extra safety margin in this era of sleep apnea when so many have that condition without even knowing it.
Based on this "safety" logic, all highway trucks should have 2 person crews. After all, trucks don't operate on fixed guideways with limited public access. They operate on public roads shared with other vehicles, including relatively frail and vulnerable passenger cars. And trucks actually operate as "trains" in many parts of the county with multiple trailers. Finally, the types of accidents that occur on RR's by operator error occur far more frequently with trucks. For example, in the Port Defiance Amtrak accident, a train turned over entering a curve too fast. How often does that really occur on railroads (and it will probably occur much less with PTC)? But, if you live in a major city, it happens almost daily with trucks on urban expressways (just listen to the rush hour traffic reports in any large city).
Bottom line: If you're advocating two person crews on trains but not on highway trucks, you're not doing it for safety reasons.