You are on a forward path.

If someone gets on you and says "I'd like to go south" and you are the north bound train, you do not change. They can get off or they can stay on, but you can't change, so you won't.

If someone demand you go east you remind them, I am the north bound train.

If they tell you to go west, you say, here are the exits. There are westbound trains elsewhere. Go find them.

And you progress forward.

The people who want to be going north will stay with you. If you go too far north for them, you let them off.

Trains do not argue with someone who says they want to go south, when the destination they say they want to go in happens to be north. That's for them to figure out. Let them go south all they want, they won't find the destination until they themselves accept they need to go north. They learn this on their own. The train doesn't teach it to them.

If someone happens to ride it til the end of the line, great! But the train doesn't go backwards, it doesn't hop to another track, and it doesn't stop for longer than it needs to.