Tier 2 for the road: the latest models from EMD and General Electric deliver new levels of performance and efficiency, and run a whole lot cleaner than their predecessors

Railway Age, March, 2005 by William C. Vantuono

German engineer Rudolf Diesel, inventor of the internal combustion powerplant that has borne his name for generations, probably never imagined just how fir the diesel engine would advance in the 112 years that have passed since his earliest prototype self-destructed during testing. The engine that revolutionized the railroad industry beginning in the 1940s was a far cry from the first commercially feasible diesels that appeared soon after the turn of the 20th Century. In turn, today's microprocessor-controlled powerplants make their 1940s predecessors look almost crude, though the principles behind them haven't changed much.

Dr. Diesel would indeed be impressed with the high-horsepower, low-emissions engines that power the latest locomotive models from the two major builders, EMD and GE Transportation Rail. They're among the most powerful and most reliable ever built. They're also the cleanest burning ever built, meeting the U.S. Environmental Protection Agency's tough Tier 2 emissions regulations, which took effect Jan. 1, 2005. An improving locomotive market has both builders working steadily on full order books, and after months of painstaking field testing, both the EMD SD70ACc and SD70M-2 (the d.c.-traction version of the SD70ACe) and the GE Evolution locomotive are hitting their stride. Several dozen of each are now in revenue service, with many more to come. Both builders anticipate strong production figures this year and next year, with total annual locomotive production approaching 1,000 units (including export units).

To the untrained eye, neither of these next-generation road locomotives look much different than their predecessors. Outwardly, the differences are subtle: cooling ducts, dynamic brake grids, other carbody characteristics--things that perhaps only the most ardent locomotive enthusiast would notice. The primemovers and their associated support systems are of course what make both of these "kings of the road Tier 2-compliant.

For EMD and GE, the approaches to achieving Tier 2 compliance are quite different. EMD took the "let's improve upon what we've got" approach. GE took a clean sheet of paper and designed a new engine. Both builders have achieved what they consider to be success.

EMD, which very shortly will no longer be a niche player in General Motors Corporation's global conglomerate following its sale to a consortium of investors led by Greenbriar Equities and Berkshire Partners, took its tried and true two-stroke 710 powerplant and modified it to meet Tier 2 regulations. "We think we have hit a home run by satisfying Tier 2 engine emissions standards with the 710 Series engine in three key markets," says EMD Director-Market Development & Communications Curt Swenson. "First, we are satisfying EPA Tier 2 emissions standards for 16-cylinder locomotives built in the U.S. starting January 2005. Second, we are also meeting UIC Tier 2 limits that apply to the 12-cylinder locomotives we build for the import markets in Europe and elsewhere. Third, we are now in compliance with the Tier 2 engine emissions standards for marine engines, two years before these standards go into effect in January 2007. The significance of this is that we have gone from a state of unregulated emissions to Tier 0, Tier 1, and Tier 2 compliance by fine tuning the 710 Series two-stroke engine without creating any new technologies or adding any complicated hardware. This has been through a significant investment by EMD in engine computer modeling, engine design and testing, software development, and engine support systems development. But this investment is paying off by providing our customers with a familiar engine that is highly reliable and also highly competitive in fuel economy."

The road to revenue service started nearly two years ago, when EMD produced four "alpha" SD70ACe (the "e" designating "enhanced") locomotives for test purposes, nos. GM70-GM73. EMD, describing its approach as a "tune-up," modified its service-proven 16-710 prime-mover (of which over 5,000 are now in service world-wide), creating the 16-710G3C-T2. The powerplant "contains no technologies unproven in the locomotive environment" and produces 4,300 hp (10% more at the rail than its predecessor) while reducing NOx emissions 50%. A combination of mechanical and electrical improvements--compression ratio modification, turbocharger parameter matching to optimize airflow for better combustion, modified electronic fuel injector timing, larger engine cooling and aftercooling systems--allowed EMD to meet and surpass Tier 2. The 710's basic dimensions were not changed; EMD says that "no additional workforce training or tooling investment is required to maintain, remove, or repair it." EMD's AESS (Auto Engine Start Stop) system assists in providing improved fuel economy.

EMD Director-Engine Design Marti Lenz lives and breathes diesel powerplants and has been with this program since the beginning. She describes a locomotive as "the platform that holds the diesel engine up." Meeting Tier 0 requirements, Lenz says, "laid the groundwork for Tier 1 and Tier 2. To meet Tier 0 requirements, we changed the engine timing and injectors. Tier 1 required a lot more work, changing the camshaft design and making other modifications."