The remaining 15 units are due to be delivered over the next six months and will take GBRf's class 66 fleet to 71 locomotives. The 2.42MW Co-Co locomotives are being built at EMD's plant in Muncie, Indiana.

Production of the class 66 will cease at the end of this year, nearly 17 years after the delivery of the first locomotive, because the EMD 710 series diesel engine is not compliant with EU Stage 3b emissions regulations, which come into force for new-build diesel locomotives in January 2015. Class 66s are in service with numerous freight operators across Europe, as well Egyptian National Railways and Setrag in Gabon.