Railways operate for a purpose. For many, operating a model railroad is not about watching a train go round and round, but about solving logical, and sometimes difficult, tasks in an efficient manner-- all while enjoying the movement.
I was first exposed to that aspect of model railroading on a friend's large basement layout, and later learned of classic shunting/switching puzzles such as the "Inglenook Siding" and the "Time Saver."
Andy's Trains offers just such operational challenges in a format that fits in your pocket.
If you have an operating model railway, this will help hone your switching and train-building skills. If you are designing an operating layout, this puzzle will present ideas for both track planning and operational fun. If you have no interest in a model railway at all, the puzzles offer a unique visual set of logic problems to be worked out in an appealing format.