This is what a lot of people don’t get about small-talk, and OP’s image touches on it, it’s not about educating someone how trains work (looking at you fellow autists) it’s about playing a short game where you gauge each other’s receptiveness to friendliness or a desire to socialize. If your small-talk partner isn’t receptive, has nothing to say and seems disinterested, you take your leave. You say “Hey I gotta run, see ya around!” and just leave it at that.

(Guys, this is also how you talk to girls you don’t know, it’s literally the entirety of volumes of pickup artist bullshit condensed into one paragraph without any weird games or sexist bullshit. Just make small-talk, see if they want to engage back, AND THEN WALK THE FUCK AWAY if they’re icy to you. If they don’t respond, that doesn’t mean they didn’t hear you, and no you don’t get a second chance in this conversation, you will make it worse if you keep trying to talk to someone not interested. I am shocked how hard this is for so many guys to understand.)