The locomotive was originally built by MotivePower five years ago and was repowered with new QSK60 diesel engines supplied by Cummins to meet the new emissions standards.

The 4.03MW engines utilise integrated Selective Catalytic Reduction exhaust after-treatment technology, which removes NOx from the exhaust stream, reducing emissions and improving fuel efficiency. The engines reduce diesel particulate emissions by around 85% and NOx emissions by around 75% compared with the locomotive's original Tier 2-compliant engines.

Metrolinx has also signed a $US 97m contract with MotivePower to supply an additional 16 new locomotives that meet the Tier 4 standards. MotivePower says the locomotives will be built to the same specifications but also include ac propulsion. Delivery of the units is expected to begin in 2017.