Back in the 1980s a few GGT commute drivers were "part time" - gave most of their paycheck to the union so nobody got rich off of it - and fit the "free ride to work" definition. They drove a commute run from Marin into SF, then used their employee pass to get to work on another GGT run or the Muni. Reverse in the evening. Weren't many of them, but there were a few. I knew one where I worked at the time.

Key difference between "full time" and "part time" was the number of commute runs: "full time" usually drove into town, then deadheaded back out for another run in, then likewise in the PM. So they didn't have time in between for a full-time other job. "Part time" only did one run each way.

One presumes that many of the "full time" drivers who worked a split shift for GGT also had some kind of job in SF. Wouldn't be surprised if a few ACE employees do likewise, though most of the tech jobs are More-Than-Full-Time so short hours between split shifts on the train might not work well. Bay Area was more of a working-class place in the 1980s than it is now. And the rest requirements are more stringent now than they used to be. So yes, van/taxi to a company-contract hotel for the time between shifts.