In this, the first book of the Grace and Pop series we introduce the main characters, Pop is Grace's grandpa and she is convinced that he is the best grandpa in the whole world. He has hundreds of stories that span his long and eventful life, and Grace loves nothing better than to sit quietly with Pop and listen to these tales. One day during Grace's long summer holiday from school, Pop took Grace on a memorable trip on an old train that was pulled by a magnificent old steam engine. During this trip, Pop's story seemed to come to life and Grace felt that she was somehow transported back to the 1930's. The big questions were. Did it happen? Did she travel back in time? Or was she just sent into a dream by the rhythmic sound of the train? Clickety Clack, Clickety Clack, Clickety Clack, Wheels on the Track . Whatever the answer was, Grace just hoped for one thing.please let it happen again, it was the best adventure ever!.