In Whyte notation, an 0-4-4 is a railroad steam locomotive that has four coupled driving wheels followed by four trailing wheels, with no leading wheels. This type is often called a Forney, after Matthias N. Forney, and is characterized by the truck under the coal bunker/water tank.
Other equivalent classifications are: UIC classification: B2 (also known as German classification and Italian classification) French classification: 022 Turkish classification: 24 Swiss classification: 2/4