Completely call it out.

Very soon after you start talking to her, assuming it seems to be headed for at least a very brief interaction, & also assuming you've shown your intent/hitting on her..

"I hope this doesn't start our train journeys being awkward"

Obviously don't say this with seriousness.

That way it'll most likely set this little bubble between both of you that when you see each other on the train or platform there'll probably be giggles about the "awkwardness" except it won't be truly awkward, it'll just be funny.