he SD80MAC is a 5,000 horsepower (3.7 MW) C-C diesel-electric locomotive. It uses a 20-cylinder version of EMD's 710G prime mover, and is the first diesel locomotive to use a 20-cylinder engine since EMD's SD45 and SD45-2. It introduced a wide radiator housing similar to GE Transportation locomotives and the placement of dynamic brakes at the rear of the locomotive, which is a quieter location, features that were incorporated into the SD90MAC and SD70ACe models. Key spotting differences between the SD80MAC and SD90MAC include no external rear sandbox on the SD90MAC, rear number boards, and the placement of the front numberboards (above the cab windows on the SD80MAC, on the nose on most SD90MACs). The SD80MAC also has recessed red marker lights in the nose, an identifying feature unique to Conrail locomotives, although Norfolk Southern (NS) has removed the lights on most of their former Conrail engines. All 30 SD80MAC units built were delivered to Conrail, and the 28 production units were completed, tested, and painted at the former Pennsylvania Railroad shops in Altoona, 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 7 updated locomotives designated as the SD80ACe model. These locomotives feature Tier 1 compliant 20-710G3C engines, with 5,300 HP (3.9MW) @ 950 RPM. The design is currently for export only, and these specific locomotives will run on Vale Mining's 5 ft 3 in (1,600 mm) broad gauge trackage. Another broad gauge variant also came in 2012 only, that is, the EMD GT50AC, also known as the Indian locomotive class WDG-5, a smaller and lighter 135-ton variant, with 5,500 HP (4.1MW) @ 910 RPM, to serve the Indian Railways, whose current tracks are weak to handle very heavy locomotives, just like how EMD GT46MAC WDG-4 was developed from SD70MAC by Reducing the weight. After the split of Conrail, the SD80MACs were split up between the Norfolk Southern Railway and CSX Transportation. Norfolk Southern received 17 units (numbered 7200–7216) while CSX got 13 (800–812, being 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 with CSX Transportation to trade 12 EMD 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, Norfolk Southern sold all 29 of its remaining SD80MACs to Canadian Pacific Railway and Progress Rail. Six units, 7206, 7215, 7218, 7225, 7226 and 7227 were sold to Canadian Pacific Railway as parts sources for their recent EMD SD70ACU rebuilds. The remainder of the NS fleet went to Progress Rail. Ex-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.
