Intriguing and unsettling
Well, this seems like an object lesson in how to write opening chapters that will hook a readers! Aside from poor Ellen's dilemma, being - literally - left holding the baby, there's the creepy guy scribbling notes and following her off the train. Is it coincidence, paranoia or some sort of sinister plot? I have no idea but I bet it's not the last surprise the author has in store for the reader.