SD70ACE

Instructions

NS SD70ACE has joined the void! history: The SD70ACe is the successor to the SD70MAC with design changes to comply with emission standards. The engine fires with 15% lower internal pressure to improve emissions and features fewer internal components in the inverter.[8] The SD70ACe is equipped with EMD's 16-710-G3C-T2 prime mover, rated at 4,300 horsepower (3,200 kW); later Tier 3 models are rated at 4,500 horsepower (3,400 kW), and have a thermal efficiency of almost 36%.[9] They are rated at 191,000 lbf (850 kN) starting tractive effort and 157,000 lbf (700 kN) continuous. Braking effort is rated at 106,000 lbf (470 kN). 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. The cab was also known for rattling, leading to the nickname "Thundercabs". As a result, these units are also not approved for leading trains.[9] In 2012, EMD also built four models known as the SD70ACe-P6. These units, unlike previous SD70ACe's, have one inverter per axle on the trucks, rather than EMD's traditional one inverter per truck design. Four of those (EMDX 1206, 1208, 1209 and 1210) were sold to Canadian National Railway and renumbered to CN 8100–8103.[citation needed] In 2014, BNSF took delivery of 20 SD70ACe-P4 units, numbered 8500 - 8519. This model was designed with a B1-1B wheel arrangement to compete with GE's ES44C4 model, which has an A1A-A1A wheel arrangement. Both wheel arrangements mean that there are only two traction motors per truck instead of three, those being the ones next to the fuel tank. Two SD70ACe-P4 demonstrators began a 5-year lease at Tacoma Rail in late 2014, and were later sold to Arkansas & Missouri Railroad in late 2023. On January 1, 2015, the United States Environmental Protection Agency's Tier 4 locomotive emission regulations went into effect. EMD could not successfully modify the SD70ACe's 2-stroke 710 series prime mover to be Tier 4-compliant; thus, the Tier 3 SD70ACe was succeeded by the SD70ACe-T4 in late 2015. However, US production of the Tier 3-compliant SD70ACe continues with Tier 4 'credit units' (new Tier 3-compliant units EMD is entitled to build based on previously earned emissions credits). 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. These locomotives are restricted to Mexico-only operation and cannot cross the US border (just as Canadian National's newest Tier 3 GE ES44AC's are restricted to Canadian use only).[citation needed] In March 2016, EMD replaced the standard cast HTCR-4 trucks on NS SD70ACe 1000 with the new fabricated HTCR-6 trucks for testing. UP and BNSF plan to test the new HTCR-6 trucks on some of their SD70ACe units also. Union Pacific received 281 additional SD70ACe units, numbered 8824 - 9104, in 2014, 2016 and 2018. These are referred to as SD70AH (T4C), H for "heavy", because they are ballasted to 428,000 lb (194,138 kg) rather than 420,000 lb (190,509 kg).