Dart is a new Diesel on the island. He helps Den run the Sodor Dieselworks. Dart is Den 's fast and feisty assistant at the Dieselworks. Dart has worked with Den for so long he can read Den's mind. Together, they run the Dieselworks well. Dart will quickly explain what Den is trying to say. No other Diesels know how to fix an engine as quickly or as capably. Dart also likes jokes, much to the annoyance of the other Diesels. He is usually cheery, but he can still get grumpy and irritable.
- Dart has very big buffers making him fairly accurate to the engine on the show.
- Dart is the second smallest standard gauge engine in the line. The first being Winston.