While not something most railroaders hoping to keep their job would admit to, the notion of teenagers (or friends or spouses or anyone else) texting or even phoning them while on duty is not far fetched at all. This reported new law to ban cell phone use in California would be a tough one for railroads to enforce or even agree to if it's not limited to personal calls, since many a job-related call gets made from the cab via cell phone now. MRAS/PBX calls to the dispatcher or other desks for lengthy conversations better kept off the main line radio channel. Not sure what "attempted cover-up" you think is obvious. Intentional sabotage? False clears? Could be. We'll see. The LA Times report on the ML engineer's personal life makes suicide seem plausible, but that's yet to be determined as well.