Given that the exact same question is the current top post but for driving instead of transit, I feel this question was needed.
My answer: I saw some guys hooking up a Raclette Grill to the outlet in an otherwise empty German intercity rail waggon. They had it unpacked in one of these 4 person seats with a small table. No idea if that could work or if draws too much power from the board net. I just headed on to the next waggon.
That’s how it is here in Seattle, too. Poor people ride the light rail, well-off people ride the light rail. If the service is good, everybody will use it.
Buses have not quite met that standard yet.