COLAS RAILFREIGHT class 70 70815 with 6V38 12.46 Carlisle Yard - Chirk loaded Logs at Garsdale Station 25th January 2020.

The Class 70 is a six-axle Co-Co mainline freight GE PowerHaul locomotive series manufactured by General Electric in Erie, Pennsylvania. The order placed in 2007 for 20 units, with an option for a further 10, for Freightliner for operations in the United Kingdom was the first order for the PowerHaul type. General Electric's product code for the class of loco is PH37ACmi.
In November 2007, Freightliner UK announced Project Genesis (unrelated to GE's Genesis series built for Amtrak), a procurement plan for 30 freight locomotives from General Electric. The locomotives ordered were intended to match older types in terms of haulage capacity whilst at the same time being more fuel-efficient. The project was a collaborative effort between Freightliner and GE, with input from drivers on the cab design.[The locomotives utilize a GE PowerHaul P616 diesel engine rated at 2,750 kW (3,690 hp).the locomotive meets EU Tier IIIa emission regulations.Freightliner expects that the locomotive's efficiency is 7% better than contemporary models, with a further 3% increase in efficiency whilst braking; regenerative braking is used to supply the energy to power auxiliary motors.

t was speculated that these locomotives would receive the TOPS classification Class 68, however the locomotives were given the Class 70 TOPS code,breaking the previous convention that class numbers in the 70s were used for DC electric locomotives.

The new locomotives are similar in appearance to a Class 58; a hood unit design with a narrow body typical of locomotive types in use in North America, the cabs are accessed from the rear via exterior walkways on the narrow part of the hood. The distinctive front end shape is due to crashworthiness features It is also fitted with air conditioning and acoustic insulation to improve the crew's environment, making it an improvement over the Class 66.

In November 2013, Colas Rail announced it had agreed a deal to procure ten Class 70 locomotives, with new builds to be assembled in Erie, Pennsylvania for entry into service in 2014; the order included the Turkish built demonstrator 70099, renumbered as 70801, and the remainder of Freightliner's original order option of 30 locomotives

Colas' locomotives were allotted numbers in the 708xx range. 70802–70805 had already been constructed at the time of the order and were shipped to the United Kingdom in January 2014, with the rest assembled and delivered later the same year. In 2015, Colas announced the purchase of an additional seven locomotives, which were delivered by 2017.Despite the number range, Colas Rail locomotives remain as Class 70/0 rather than 70/8.