The worst thing I have ever bought in terms of quality. I had to exchange it twice because all the cars had a specific defect: the engine gear was detached from the gear that gives motion to the wheels, and some cars also lost power. And we're not just talking about this specific series, but also two other different series from the same company. The good thing is that it was purchased from a well-known toy chain and we didn't have any trouble exchanging it both times without even opening the packaging