The British Rail Class 97/6 0-6-0 diesel shunting locomotives were purpose-built for departmental duties by Ruston & Hornsby at Lincoln in 1953 (97650) or 1959 (97651-654). There are minor technical differences between 97650 and the 1959 batch.

This class of five locomotives is outwardly similar to the Class 04 diesels built around the same time, but internally they are quite different. The Class 97/6 is diesel-electric, while the Class 04 is diesel-mechanical. 

The Class 97/6 is related to the older British Rail Class D1/3, which was a 0-4-0 diesel-mechanical version of the Ruston & Hornsby 165DE. All existing now preserved.