- four (4) leading wheels (at the front of the locomotive)
- four (4) driving wheels (2 axles) fixed in a rigid frame, and
- six (6) trailing wheels (normally mounted in a trailing truck).
The only example of this wheel arrangement was the Thuile locomotive.
Other equivalent classifications are:
- UIC classification: 2'B3' (also known as German classification
- Italian classification), and
- French classification: 223.