The Zoo Train App looks like a fun educational app for preschoolers which focuses on two topics that most young children love - animals and trains. The App includes five games to help young learners develop skills, including a word building game, train building game, train whistle music game, track building puzzle game, picture puzzle game and reward stickers.
It is available on the App store for $1.99. Although I have not tried the app, the reviews for it look very positive. If you have tried this app, please provide your feedback.