I remember watching a news report from a while ago where they noted that a lot of engineers are tired on the job as well.
Economics would dictate that there be an overlap of "crews" (On this and other MMA trains they have equipment that allows the crew to be just one person) so the train would always be manned and spend more time moving.
There should have been two engineers on the job. The company was running big risks by running so bare boned.
For the sake of $100,000 engineer, a billion dollar accident happened.