9Hop on board the Play Train This eye-catching set combines three toddler favorites: trains, jigsaw puzzles, and early-learning fun. The set includes three shaped board books that slot together to form a colorful train for children to play with. Each chunky book focuses on a key early-learning concept: colors, numbers, and words. With a fun design sure to delight and entice little train fans, this engaging set is an ideal way to introduce young children to educational play.