British Rail Class 97
classification for departmental (non-revenue) locomotives
British Rail reserved the TOPS Class 97 designation for departmental locomotives. These were used for special or engineering duties. They were therefore of several different classes, lumped together for numbering purposes. Some locomotives were converted from redundant engines, whilst others were purpose built. In 2008, Network Rail once again used Class 97 for signalling test locomotives (Class 97/3).
