405
This three-sided pole on an airport tram
(sh.itjust.works)
I had never seen one of these before today. They're great. Way better than reaching for a single pole in a crowded car and wrapping your hand around some stranger's fingers. And If you have the whole thing to yourself you can hook your arm through it.
Yup this is how you do it. I ride the train standing up without holding anything all the time. If you stand perpendicular and lean during accel/decel it's very stable. If you are facing parallel to the trains direction you're gonna faceplant.