MotivePower will replace the 16-cylinder EMD 710GB series diesel engines with twin Cummins QSK60s, making them the first passenger locomotives in North America to comply with US Environmental Protection Agency Tier 4 emissions standards. The new engines will reduce diesel particulate emissions by around 85% and Nitrous Oxide emissions by around 75% compared with current models.

The first re-engined locomotive will be completed in 2014.

MotivePower is still delivering batches of MP40s to Go Transit, and the fleet could eventually total 77 locomotives if all options are exercised.