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TheEMD SD80MAC was a 5,000horsepower (3.7 MW)C-Cdiesel-electric locomotive. It was powered by a 20-cylinder version ofEMD's 710G prime mover, and was the second diesel locomotive by GM-EMD to use aV20 engine, since EMD'sSD45 series. It introduced a wide radiator housing similar toGE Transportation locomotives and the placement ofdynamic brakes at the rear of the locomotive, which is a quieter location, features that were incorporated into theSD90MAC andSD70ACe models. Key spotting differences between the SD80MAC and SD90MAC include no external rear sandbox on the SD90MAC, no rear lighted number boards on the SD90MAC, and the placement of the front number boards (above thecab windows on the SD80MAC, on the nose on most SD90MACs). The SD80MAC also had recessed red marker lights in the nose, an identifying feature unique toConrail (CR) locomotives, althoughNorfolk Southern (NS) had removed the lights on most of their former Conrail engines.
All 30 SD80MAC units built were delivered toConrail, and the 28 production units were completed, tested, and painted at the formerPennsylvania Railroad shops inAltoona, Pennsylvania.
Prior to the 1995 merger with Union Pacific,Chicago and North Western Railway placed an order of 15 locomotives.Canadian Pacific placed an order as well but it was changed to SD90MACs. Conrail planned a second order of SD80MACs, but its new owners changed the order to SD70s and SD70MACs, all of which would be built at the Juniata Shops in Altoona.
Vale Mining of Brazil ordered a set of seven updated locomotives designated as theSD80ACe model. These locomotives feature Tier 1 compliant 20-710G3C-ES engines, with 5,300 hp (4.0 MW) at 950 RPM. The design is currently for export only, and these specific locomotives will run on Vale Mining's5 ft 3 in (1,600 mm) broad gauge trackage.
Another broad gauge variant introduced in 2012 is theEMD GT50AC, also known as theIndian locomotive class WDG-5, a smaller and lighter 135-ton variant, with an up-tweaked EMD 20N-710G3B-EC engine, capable of producing 5,500 hp (4.1 MW) at 910 RPM, to serve theIndian Railways, whose current tracks are weak to handle very heavy locomotives, just like howEMD GT46MAC (a) WDG-4 was developed fromSD70MAC by reducing the weight. The seven locomotives of the class were developed indigenously byBanaras Locomotive Works (BLW) ofIndia. The locomotives are not a part of the SD80 series, but are completely based on it, making it the second International application of the V20-710 prime mover, after the Brazilian SD80ACe.
After the split of Conrail in 1999, the SD80MACs were split up betweenNorfolk Southern Railway andCSX Transportation. Norfolk Southern received 17 units (numbered 7200–7216) while CSX got 13 (800–812, renumbered to 4590–4602). The former Conrail units were the first AC traction locomotives owned by Norfolk Southern, with the railroad not ordering more until late 2008 with an order of General Electric's ES44AC. In late 2014, Norfolk Southern announced that they had reached an agreement withCSX Transportation to trade 12EMD SD40-2 units (NS 3425–3447) for CSX's remaining 12 SD80MACs, leaving NS as the model's sole operator. They were delivered to the NS in April 2015.
In February 2020, following the beginning ofCOVID-19 pandemic, Norfolk Southern retired all 29 of its remaining SD80MACs, owing to their operational costs. Six units were sold toCanadian Pacific Kansas City (then Canadian Pacific Railway) as parts sources for their recentEMD SD70ACU rebuilds. The remainder of the NS fleet went toProgress Rail and were scrapped. As of January 2022, the Conrail Historical Society was in contact with Canadian Pacific Kansas City Limited hoping to have one SD80MAC set aside for preservation, after failing to make an agreement with Progress Rail. As of 2025, the six SD80MACs still remain in storage as the remainder were scrapped.[1]
CSX 4594, formerly CSX 804, and built as CR 4110, was scrapped in January 2014 after being used as a parts donor following a derailment in early 2009.
A Norfolk Southern South Fork crew was securing their engines for the night on November 18, 2016 when an electrical fire broke out in the cab of NS 7210 (built as CR 4118). There were no injuries, but the SD80MAC’s cab interior was completely destroyed. The unit was hauled to the Juniata Shops in Altoona where it was stored in the deadline until it was among the units that were sold off to Progress Rail. The unit was scrapped in December 2021.
The technical details of this locomotive model are as follows:[2]