EMD SD70ACe

The EMD SD70ACe entered production in 2004 as the direct successor to the SD70MAC, developed primarily to meet the United States Environmental Protection Agency's Tier 2 diesel emissions standards that took effect on January 1, 2005. Electro-Motive Diesel designed the model to carry forward the AC traction technology of the SD70MAC while incorporating significant revisions to the engine management and emissions systems. The locomotive quickly attracted orders from major Class I railroads in North America, and over the course of its production run, which extended through at least 2022, more than 1,600 units were built, making it one of the more commercially successful members of the SD70 family. Among the primary customers for the SD70ACe were BNSF Railway, Union Pacific, Norfolk Southern, and CSX Transportation, all of which operated large fleets of the type across their respective networks. The model assumed heavy freight duties across the continental United States, handling coal, intermodal, and general merchandise trains. Early production units were noted for certain cab comfort shortcomings, with crew members on some roads reporting elevated noise levels and vibration intrusion from the prime mover, an issue that EMD addressed in subsequent production batches through revised cab isolation and interior treatments. The SD70ACe occupies a significant place in North American diesel locomotive history as the model that carried EMD's established 710-series engine platform into the Tier 2 and later Tier 3 regulatory eras, competing directly against General Electric's ES44AC. Its long production span and widespread adoption across the largest freight railroads in the United States reflect its durability and operational reliability, and substantial numbers of the type remain in front-line service well into the 2020s.

The SD70ACe is powered by the EMD 710G3B-EC, a 16-cylinder two-stroke diesel engine rated at 4,300 horsepower, paired with an AC traction system that employs three-phase inverter technology to drive the locomotive's six traction motors arranged in a C-C wheel configuration on two trucks. To achieve compliance with emissions regulations, the engine was modified to fire at approximately 15 percent lower internal cylinder pressure compared to earlier variants, which reduced particulate and nitrogen oxide output while the inverter assembly was simplified through a reduction in internal components. The locomotive rides on EMD's HTSC trucks as standard, a non-radial bolsterless design derived from the earlier radial HTCR truck, with the radial version remaining available as an option for customers who preferred it. Starting tractive effort is rated at 191,000 pounds-force, with continuous tractive effort of approximately 157,000 pounds-force, and dynamic braking effort of around 106,000 pounds-force, figures that placed the SD70ACe in the same general performance class as its principal competitors during its production years.

Models by: Athearn · Bachmann · Broadway Limited · MTH · Walthers