So at first I had ZERO idea why this train kept going back and forth. It really is funny, but I can't even imagine how I would react if I was late to something and this was happening right in front of my face. Someone on Instagram commented:
he's setting out/picking up cars. That's how they deliver stuff. Usually there's adjacent tracks off the main track and to access the different tracks, the engineer has to pull forward past the switch, then the conductor or brakeman lines the switch for whatever track they need to access. They then back up into that track and either pick up or set out cars there. They may have to do the same process multiple times depending on what track the cars need to be delivered to or picked up from. Sometimes they need the cars in a certain order so they have to make several moves like that. It's called switching. Sometimes if the train crew is nice and they have to switch over an intersection like that, they will stop behind the crossing and let the gates go up and let traffic cross every now and then.
I would have lasted about 10 minutes tops before you found me driving the wrong direction just to get the hell outta there.