In other words, the problem isn't a "lack of crew", it's poor safety standards with regards to handling the results of defect detectors, combined with overly-long trains. The biggest problems with the long trains themselves are stopping distance and "how long it takes the crew to walk back to inspect it."
The former is what led to the derailment, as they couldn't stop the train in the time between the last detector going "holy fuck" and the wheel falling off, and the latter leads to even more management pressure against stopping the train if a defect is perceived as "marginal": a stopped train not only delays the train, it delays the *line*, and the longer that train is stopped (because it takes fucking forever for the engineer to walk a mile down and back to inspect it) the bigger the hit to the company pocketbook.