The Idea Factory - Adventurer 2
Sometimes, I get ideas from dreams, write them down in the middle of the night, and they make no sense in the light of day. Not sure if this is one of them or not.
New grad takes a gap year from college to travel across the country. Someone confronts them on the first train, telling them to do something illegal or they will derail the train. The girl doesn't but he makes it look like she did. She goes on the run but someone online believes her and starts a hashtag (#Adventurer2). She finds out halfway through the book and starts using it to try to find the guy and clear her name.