That's probably an unusually good commuter rail system. I'm about a 10 minute drive from a less frequent commuter rail, so figure 15 minutes out the door until the scheduled train comes. There don't seem to be any express trains running right now so it's over an hour into the city and that's assuming I don't need to catch a subway on the other end--which I would have to do to go to my company's city office. So, for me, at least 90 minutes--and that's for someone fairly far out (it would also take me a good 60 minutes to go in by car with nominal traffic but more like 90 anywhere near rush hour even leaving early) but convenient to a rail line.

I actually did this for a time, fortunately not every day but frequently enough. Wouldn't really have been sustainable long term.