Union Pacific Tier 4? Scrubber on Exhaust 9900 - Trains Magazine

In today's Trains Newswire, GE introduced their Tier 4 compliant locomotive prototype.  It uses no EGR, DPF or DEF according to the news release.  That release follows for those of you who are not subscribers.

ERIE, Pa. – GE Transportation unveiled the first new production prototype Tier 4 emissions capable locomotive today at its manufacturing facility in Erie. As part of a kickoff event attended by GE employees; federal, state, and local officials; and print and television journalists, the Tier 4 prototype ES44AC, appropriately numbered 2015 and decked out in GE's "Ecomagination" colors, burst through a large banner to make its debut.

This next-generation Evolution Series locomotive meets Tier 4 requirements that take effect in 2015 with the existing GEVO12 prime mover and without the need for urea-based after-treatment, a condition that the railroad industry has been insistent upon.

No. 2015's extended-height engine hood and massive radiator section are a hint at the extensive technological advancements necessary to meet Tier 4 emissions requirements and to achieve the mandated 70 percent reduction in emissions by 2015