EMD SD90MAC
Model of American diesel-electric locomotive
title: "EMD SD90MAC" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["c-c-locomotives", "diesel–electric-locomotives-of-the-united-states", "diesel-locomotives-of-western-australia", "electro-motive-diesel-locomotives", "freight-locomotives", "railway-locomotives-introduced-in-1995", "standard-gauge-locomotives-of-the-united-states", "electro-motive-division-locomotives", "standard-gauge-locomotives-of-canada", "standard-gauge-locomotives-of-australia", "diesel–electric-locomotives-of-australia", "diesel–electric-locomotives-of-canada", "canadian-pacific-railway-locomotives", "norfolk-southern-railway-locomotives", "union-pacific-railroad-locomotives"] description: "Model of American diesel-electric locomotive" topic_path: "geography/united-states" source: "https://en.wikipedia.org/wiki/EMD_SD90MAC" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Model of American diesel-electric locomotive ::
::data[format=table title="Infobox locomotive"]
| Field | Value |
|---|---|
| name | EMD SD90MAC and SD9043MAC |
| powertype | Diesel-electric |
| gauge | |
| image | Union Pacific Railroad EMD SD90MAC-H.jpg |
| caption | Union Pacific 8540, an SD90MAC Phase II |
| builddate | 1995–1999 |
| totalproduction | 657 |
| buildmodel | SD90MAC |
| builder | Electro-Motive Diesel (EMD) |
| poweroutput | {{Plainlist |
| * SD9043MAC: {{convert | 4300 |
| * SD90MAC: {{convert | 6000 |
| aarwheels | C-C |
| uicclass | Co’Co’ |
| length | 80 ft |
| locoweight | 415000 lb (SD9043MAC) and 425000 lb (SD90MAC-H & SD90MAC-H2) |
| fuelcap | 5000 usgal |
| sandcap | 40 cuft |
| enginetype | V16 diesel |
| maxspeed | 70 mph |
| cylindercount | 16 |
| rpmrange | 225-1,000 rpm |
| wheeldiameter | 45 in |
| cylindersize | 10.45 x |
| tractionmotors | 6 Siemens 1TB2830 AC motors |
| tractiveeffort | Small engine (SD9043MAC): 185000 lbf starting, 147000 lbf continuous |
| Large engine (SD90MAC-H and SD90MAC-H2): 200000 lbf starting, 165000 lbf continuous | |
| primemover | EMD 16-710 G3C-T1 and 16-265H |
| :: |
| name=EMD SD90MAC and SD9043MAC | powertype=Diesel-electric | gauge= | image=Union Pacific Railroad EMD SD90MAC-H.jpg | caption=Union Pacific 8540, an SD90MAC Phase II | builddate=1995–1999 | totalproduction=657 | buildmodel=SD90MAC | builder=Electro-Motive Diesel (EMD) | poweroutput={{Plainlist|
- SD9043MAC: 4300 hp
- SD90MAC: 6000 hp | aarwheels=C-C | uicclass=Co’Co’ | length=80 ft | locoweight=415000 lb (SD9043MAC) and 425000 lb (SD90MAC-H & SD90MAC-H2) | fuelcap=5000 usgal | sandcap=40 cuft | enginetype=V16 diesel | maxspeed=70 mph | cylindercount=16 | rpmrange=225-1,000 rpm | wheeldiameter=45 in | cylindersize=10.45 x | tractionmotors=6 Siemens 1TB2830 AC motors | tractiveeffort=Small engine (SD9043MAC): 185000 lbf starting, 147000 lbf continuous Large engine (SD90MAC-H and SD90MAC-H2): 200000 lbf starting, 165000 lbf continuous | primemover=EMD 16-710 G3C-T1 and 16-265H}}
The EMD SD90MAC is a model of 6,000 hp C-C diesel-electric locomotive produced by General Motors Electro-Motive Division (EMD). It is, with the SD80MAC, one of the largest single-engined locomotives produced by EMD and among the most powerful diesel-electric locomotives, surpassed only by the dual-engined DDA40X.
The SD9043MAC is the 4,300 hp variant, using a 16-cylinder 710G engine instead of the H-engine, which was originally intended as a temporary alternative while EMD tried to solve the H-engine's issues. However, the accompanying upgrade program was never utilized by its customers.
The SD90MACs features include radial steering trucks with AC traction motors and an isolated safety cab which is mounted on shock absorbers to lessen vibrations in the cab. The SD90MAC, like the SD80MAC, SD70ACe, and SD70M-2, has a wide radiator section, nearly the entire width of the locomotive, which along with their size makes them easy to spot.
As of 2019, some SD90MACs are still in service on the Union Pacific. Norfolk Southern had rostered 110 SD90MAC locomotives purchased or traded from Union Pacific or the CIT Group respectively, that have now all been rebuilt as EMD SD70ACU locomotives. Canadian Pacific has also opted to convert their small fleet of long-stored SD90MACs into SD70ACUs as well.
History
::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/0d/UP_8027_EMD_SD9043AC.jpg" caption="[[Union Pacific]] SD9043MAC locomotive No. 8027"] ::
The SD90MAC was introduced in 1995, along with the SD80MAC locomotives. The SD90MAC was designed to utilize the new 16-cylinder H-engine, while the SD80MAC was designed to use the 20-cylinder version of the existing 710G engine. However, technical problems with the 6000 hp engine resulted in the first locomotives being shipped with 4300 hp 16-cylinder 710G engines, making them similar to the SD70MACs. These locomotives were informally designated SD9043MAC by railroads that purchased them with the option to re-engine them with 6000 hp engines when they became available. This upgrade program, however, was never taken advantage of by SD90MAC buyers due to reliability issues with the newer engine. Over 400 SD90MAC locomotives fitted with the 4300 hp 710 engine were built.
In 1996, Electro-Motive Diesel entered full production on their 6000 hp, 16-cylinder H-engine, and all SD90MACs made from then on used that for its prime mover. Locomotives fitted with this engine are sometimes referred to as SD90MAC-H locomotives. Later versions of the SD90MAC-H feature a Phase II cab, with a new nose which offers higher visibility from the cab than the old nose. The SD90MAC-H did not prove popular with railroads and less than 70 were built, including Electro-Motive Diesel demonstrator units.
Since the SD90MAC-H had such a large prime mover, it didn't offer the same operational flexibility as smaller units, limiting its possible customer base to only the largest railroads. Also, since the H-engine was a new design, it hadn't reached the same level of reliability as EMD's previous engine. The low reliability on such a large engine was an especially bad combination since the loss of one engine in a train meant the loss of a larger percentage of pulling power than had a smaller engine failed. In the end, the SD90MAC-H was only delivered to two railroads; the Union Pacific and Canadian Pacific. The Canadian Pacific locomotives were part of an earlier order for 710-engine equipped SD90MAC locomotives that was still in production when Electro-Motive Diesel switched over to the H-engine.
Electro-Motive Diesel also tried offering a lower-power version of the SD90MAC with a 12-cylinder engine called the SD89MAC, but none were produced other than the prototype.
Specifications
::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/9b/NS_7332_EMD_SD90MAC_(33276291851).jpg" caption="[[Norfolk Southern]] 7332 in Ohio"] ::
Prime mover (EMD 710):
Prime mover (EMD 265):
- EMD V16 EMD GM16V265
- Power Output - 6,000 hp at 1,000 rpm
- Idle - 200 rpm
- Full speed - 1,000 rpm
Traction motors:
- 6 Siemens 1TB2830 AC motors mounted 3 each on 2 HTCR-2 radial self-steering trucks.
- Rated output - 855 hp
- Gearing - 83:16
- Wheel size - 45 in
- Max revolutions - 3,435 rpm
- Starting torque - 16,300 N·m
- Continuous torque - 12,900 N·m
- Maximum voltage - 2,183 V
Performance (parenthesis indicate H-Engine equipped specifications):
- Maximum speed - 70 mph
- Starting tractive effort - 185,000 lbf and 200,000 lbf)
- Continuous tractive effort - 147,000 lbf and 165,000 lbf)
- Braking effort - 115,000 lbf
- Weight - 210 ST/420000 lb
Fleet rosters
::data[format=table title=""]
| Railroad | Quantity | Road Numbers | Notes | SD9043MAC | SD90MAC-H | SD90MAC-PII |
|---|---|---|---|---|---|---|
| Canadian Pacific | 61 | 9100-9160 | url=https://www.railwayage.com/mechanical/progress-rail-to-upgrade-cp-units/ | title=Progress Rail to upgrade CP units | date=26 June 2018}} It was later announced that the order would be upped to 60 units in total, using the remainder of the 58 usable cores from the long-stored SD90MAC fleet and buying two SD90MACs from the Union Pacific to make up the difference. In 2021, Canadian Pacific purchased 40 more SD90MACs from Union Pacific for further continuation of the SD70ACU rebuild program. | |
| CEFX | 40 | 100-139 | Units are on lease fleet. 10 units traded to Norfolk Southern for 15 MP15DCs. | |||
| Indiana Rail Road | 14 | 9001-9013, 9025 | These units are on long-term lease from CEFX. All to be retired and sold to NS for SD70ACU rebuilding. | |||
| Norfolk Southern | 110 | 7229-7338 | NS purchased 100 units in September 2014 from EMD/Progress Rail. Those units are ex-UP. 10 units were acquired from CEFX in June 2016, in exchange for 15 MP15DCs. All units have been converted to SD70ACUs. 65 of them sold to PRLX. 30 of the PRLX units were sold to Ferromex in 2024. Unit 7314 was renumbered to 7339. | |||
| Union Pacific | 309 | 8000-8308 | Most of them were renumbered 3470–3775 to make room for new GE ES44ACs. Both the Norfolk Southern and Canadian Pacific have purchased locomotives from Union Pacific's fleet for SD70ACU rebuilds; in September 2014, Norfolk Southern purchased 100 of these and in 2019 and 2021 Canadian Pacific purchased 42 of these in total. | |||
| Fortescue | 5 | 905-909 | Ex Union Pacific 8527, 8530, 8531, 8541 & 8554, rebuilt from SD90MAC-Hs at Juniata Shops | |||
| Canadian Pacific | 4 | 9300-9303 | These were scrapped in Lachine, QC. https://web.archive.org/web/20110308002353/http://www.canadianrailwayobservations.com/2011/mar11/mar11locoworks.htm | |||
| EMLX | 40 | 8500, 8523-8561 | Former Union Pacific 8500, 8523-8561, currently stored. All leased to Kansas City Southern (KCS) in 2008 on a one-year lease. Several went to the Buffalo & Pittsburgh Railroad upon returning from KCS lease. All currently stored. 8522, 8527, 8529-8531, 8539, 8541, 8549 & 8554 sold in 2011 to Fortescue in Western Australia. Have since been sold to many different owners, primarily for scrap. | |||
| Union Pacific | 62 | 8500-8561 | Fleet Retired, some after less than 5 years of service. 8500, 8523–8561 to EMLX Lease fleet, 8501-8522 renumbered 8911-8931. Retired in late 2008-2009. Sold to Metro East Industries in Alorton, Illinois. Scrapped mid to late 2009. | |||
| Fortescue | 4 | 901-904 | ex Union Pacific 8522, 8529, 8539 & 8549, rebuilt Juniata Shops | |||
| Fortescue | 8 | 910-917 | Ex Union Pacific 8538, 8548, 8550, 8557, 8525, 8533, 8543 & 8547, rebuilt by Progress Rail, Mayfield, Kentucky, all scrapped 2022 | |||
| :: |
Current status
::figure[src="https://upload.wikimedia.org/wikipedia/commons/6/69/Ns_train_238_with_a_SD70ACU.jpg" caption="[[Norfolk Southern]] SD70ACU No. 7305. The SD70ACU was part of Norfolk Southern's SD90MAC rebuild program."] ::
As of January 2005, the SD90MAC is no longer in production due to the Environmental Protection Agency's Tier 2 locomotive emission regulations, although EMD had planned to be able to get the H-engine approved at some later date. However, China recently announced an order for 300 JT56ACe locomotives, which also use the H-Engine as its prime mover. A portion of the locomotives will be assembled in kit form by China's own Dalian Locomotive Works. These units were reportedly capable of meeting the EPA's strict regulations and began delivery in the latter half of 2007.
Due to reliability issues, Fortescue units 910 to 917 were stored. They were purchased to be used as slave units, and were more offline than they were in use. All were scrapped in 2022.
On 1 August 2008, Union Pacific announced that it would be retiring 21 of the SD90MAC locomotives. Common parts will be used to maintain the railroad's 710-engined SD90MAC fleet. The 265H prime mover will be cut up or exported. The only part that is not reusable is the frame. These units, in the 8900 series will be removed from storage in Denver, and will be sent to East St. Louis, in small batches to be dismantled. As of 2019, Union Pacific still operates some of the remaining SD9043MACs, which sport new numbers and UP wings on the cab. These units take the original road numbers of the Union Pacific's original SD40-2 fleet.
Canadian Pacific's SD90MAC-H locomotives 9300-9303 (listed as SD90MAC6000s) were up for tendered sale in 2009. The bidding ended 31 March 2010. While they were originally thought to be shipped overseas, they were eventually moved to Quebec for scrapping.
Canadian Pacific's SD90MAC locomotives, numbered in the 9100–9160 series had been in long-term storage in Winnipeg, Manitoba, for much of the 2010 decade. Three units, the 9129, 9133 and 9138, were scrapped in November 2012 due to errors in preparing them for long-term storage. The entire fleet had been put up for sale in November 2012 and again in January 2013 with no offers being received. These units remained stored until the winter of 2018 when at first 30, then all 58 remaining units entered a rebuild program to be converted into SD70ACUs. In 2021, Canadian Pacific purchased 40 more SD90MACs from the Union Pacific for further rebuilding into SD70ACU engines.
In September 2014, Norfolk Southern purchased 100 4300 hp SD9043MACs from Union Pacific with the intent to rebuild them into SD70ACUs at the Juniata Shops. The last four SD90MACs were delivered to Norfolk Southern on October 3, 2015, running parallel to Western Avenue in Chicago.
In 2015, Cummins rebuilt a single SD90MAC with its QSK95 engine, designed to meet Tier 4 emissions standards. Sygnet Rail Technologies and Brookville Equipment Corporation performed the conversion. The rebuild was designated HTL4200AC. The locomotive, numbered CECX No. 1919, had been Union Pacific No. 8559.
References
References
- "Gm Emd: Sd90Mac".
- Johnston, Howard. (2005). "Jane's Train Recognition Guide". Collins.
- "EMD SD90MAC Data Sheet". The Diesel Shop.
- "Diesel-Electric Locomotive SD90MAC with Three-Phase Drive". [[Siemens]].
- (26 June 2018). "Progress Rail to upgrade CP units".
- wrp_admin. (2023-03-16). "Last Dance for Indiana Rail Road SD90MACs".
- says, Vincent Saunders. (2023-08-15). "Indiana Rail Road's SD9043MACs are fading out".
- FMG SD90MACs Arrive ''[[Motive Power]]'' issue 75 May 2011 page 9
- Fortescue SD90MACs on Their Way ''Motive Power'' issue 74 March 2011 page 9
- Clark, Peter. (2012). "An Australian Locomotive Guide". Rosenberg Publishing.
- The path to 155 million tonnes ''[[Railway Gazette International]]'' June 2011 page 42
- MotivePower Roundup ''Motive Power'' issue 137 September 2021 page 61
- As at October 2024, six SD90MAC-Hs remained in service with two in store.Australia Wide Fleet List ''Motive Power'' issue 156 November 2024 page 41
- (November 10, 2015). "Cummins Tier 4 freight locomotive headed to Indiana for testing". [[Trains (magazine).
::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::