Under the Whyte notation for the classification of steam locomotives, 4-4-4 represents the wheel arrangement of four leading wheels on two axles, four powered and coupled driving wheels on two axles, and four trailing wheels on two axles. In the United States, this arrangement was named the Reading type, since the Philadelphia and Reading Railroad was the first to use it. In Canada, this type is known as the Jubilee.
Other equivalent classifications are:
- UIC classification: 2B2 (also known as German classification and Italian classification)
- French classification: 222
- Turkish classification: 26
- Swiss classification: 2/6