I bought this along with Percy. He spent half an hour pushing the trains around the track saying to himself 'Emily, Percy, Emily, Percy', with the odd 'Silly Emily' interjected. Although the track we use is not specifically designed for these trains (we bought it from Ikea)it really doesn't matter to our son. In fact he now wants Gordon and the Fat Controller.
If your little one loves trains then these little magnetic toys are brilliant.
Emily's carriage is detachable and held together by the magnets, so it can be towed by other engines.