Other than the CR paint scheme these units were built to NS specifications and numbered (2557 - 2580) in series with Norfolk Southern's already purchased SD70s.

In February 2017, NS began a program to convert its SD70s from DC to AC, which will also have a new wide-nose cab, and several other upgrades.

CVG Ferrominera Orinoco has 6 SD70Ms that were built as an add-on order to UPs FIRE cab equipped SD70Ms.

Companhia Vale do Rio Doce (CVRD) in Brazil has ordered 55 of this model for service for the Carajás mine pulling trainloads of iron ore.

Since CVRD track is gauged at 1,600 mm (5 ft 3 in), a wider bogie, the HTSC2, was designed for these units by EMD.

[5] The SD70I is a version of the SD70 which has been fitted with a cab that is isolated from the frame of the locomotive with rubber gaskets (officially known as a "WhisperCab").

In total, 1,109 SD70MACs were produced, purchased by Burlington Northern (and its successor, BNSF), Conrail, CSX, Transportación Ferroviaria Mexicana (TFM; units now owned by Kansas City Southern Railway (KCS)), and the Alaska Railroad.

Early models featured a bad cab design which was noticed first on CSX as crews reported annoying disturbances such as prime mover noises, traction motors and more.

On January 1, 2015, the United States Environmental Protection Agency's Tier 4 locomotive emission regulations went into effect.

Union Pacific and Norfolk Southern are currently the only US roads to own Tier 4 credit unit SD70ACe's.

Additionally, EMD has continued building Tier 3 SD70ACe's for Ferromex (4100–4118), Ferrosur (4119–4133), and Kansas City Southern de Mexico (4200–4224) at Bombardier Ciudad Sahagun.

Norfolk Southern ordered 130 SD70M-2s, of which 46 remained in service as of July 2023 with 2 units rebuilt with AC traction.

The first locomotive, EMDX 1501, was built in summer 2015, and made its debut at the Railway Interchange Expo in Minneapolis, Minnesota during the weekend of October 3–4, 2015.

The results of this setup are higher power throughout a broader RPM range, better fuel efficiency, and lower emissions.

Another new feature of this engine is the Double-Walled Fuel Injection System that increases safety and provides simplified maintenance works.

[19] With a new computer software for the on-board computer and one inverter per axle (or "P6"; EMD named it "Individual Axle Control") - unlike most of previous EMD locomotives that use one inverter per truck, the SD70ACe-T4 is capable of generating 200,000 pounds-force (890 kN) of starting tractive effort, and 175,000 pounds-force (780 kN) of continuous tractive effort.

[19] While it retains the basic SD70 designation, the locomotive has several major new features that set it apart from its successful ancestor such as a vibration-isolated powertrain, and alternator start capability.

In addition, it features a newly redesigned cab reminiscent of the earlier SD70M, featuring the classic "teardrop" windshields first introduced on the FP45 in December 1967; new fabricated trucks; a longer frame at 76 feet 8 inches (23.37 m); longer radiators with three radiator fans instead of two; an additional step on the front and rear; and a smoother long hood roofline.

[24][page needed] In 2004, BHP Billiton ordered 14 SD70ACe/LCi locomotives for use on iron ore trains in the Pilbara region of Western Australia.

[29] They were overhauled and sold to Chemin de fer Arnaud (4), Montana Rail Link (4) and Quebec North Shore & Labrador (5).

An order for a third batch of 13 SD70ACe/LCi's (4334–4346) was placed in August 2007, but such was the demand for locomotive power in the Pilbara region, a deal was done with BNSF for BHP Billiton to purchase ten standard North American SD70ACes (4324–4333) that were in build as their 9166, 9167, 9184–9191.

Construction was sufficiently advanced when the deal was concluded for them to have been painted, hence they were delivered in BNSF orange livery.

[24][page needed][26] An additional 18 units (numbers 4356–4373) were delivered in the second half of 2010, bringing the total of SD70ACe type locomotives in service to 72.

The first 25 units were ordered for Saudi Railway Company in April 2009 and assembled in the London, Ontario, plant for delivery in the second half of 2010.

[39] In October 2015, EMD started producing SD70ACe-BB locomotives for Brazilian 1,000 mm (3 ft 3+3⁄8 in) railroads.

[citation needed] Canadian Pacific has also begun a program to convert their SD90MAC units into SD70ACUs, but unlike Norfolk Southern, Progress Rail is performing the rebuilds.

[46] Canadian Pacific originally rostered 61 SD90MACs, which spent much of the 2010-decade parked in long-term storage, with the exception of three, which were retired and scrapped in 2012.

The SD70ACC is rated at 4,500 horsepower (3,355.649 kilowatts), has a fuel capacity of 4,900 US gallons (19,000 L), and has dynamic braking, cab signals, and LSL (Locomotive Speed Limiter).

The rebuild also includes the addition of head end power (HEP) along with meeting Tier 3 emissions.

[84] The locomotive, painted in honor of George H. W. Bush, was unveiled in October 2005 and was in active service until 2009, when it was placed into storage due to the financial crisis of 2007–2010.