Alaska Railroad participated in the overhaul and emission upgrade on two GP 40-21 locomotives. The diesel stimulus funding was used to bring locomotives 3007 and 3008 into Tier 0+ compliance and three full-time employees were sustained by the effort.

Emission equipment installations resulted in significant reductions of the noxious emissions of harmful chemicals, such as nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM₁₀) for each operating hour of the locomotive units. Automatic engine stop-start equipment (AESS) was installed in the locomotives which allow locomotive engine shut-down to occur instead of idling in stand-by mode. As a result of the reduced idle time for an operating locomotive, the AESS is anticipated to provide diesel fuel usage savings as well as the reduced emission output.

The overhaul and upgrade also complied with the EPA Final rule of May 2008 to meet certain specified emission minimums, which for these locomotives were, to be in Tier 0+ emission compliance standards.

See photos of the locomotives (PDF) before overhaul/upgrade.

Locomotives after overhaul/upgrade. (Photos courtesy of Alaska Railroad)