# GE AC6000CW

The AC6000CW is a 6,000-horsepower (4,500 kW) diesel electric locomotive built between 1995 and 2001 by GE Transportation. It is among the world's most powerful single-engined diesel locomotives. The locomotive was designed for extremely high horsepower needs, such as pulling heavy coal and ore trains. Most examples were purchased by two railroads: Union Pacific and CSX.

## Design and production

The AC6000CW was designed at the height of a horsepower race between the two major locomotive manufacturers, Electro-Motive Division of La Grange, Illinois with the SD90MAC, and GE Transportation of Erie, Pennsylvania with the AC6000CW, in the early to mid 1990s. The goal was 6,000 horsepower (4,500 kW).
GE worked with Deutz-MWM of Germany in 1994 to design and construct the 6,250-horsepower (4,660-kilowatt) 7HDL engine for the locomotives. The first locomotive with a 7HDL was the "Green Machine" GE 6000, nicknamed for its green paint scheme. The first production models were also built in 1995: CSX Transportation 600-602, and Union Pacific Railroad 7000-7009. All these locomotives were released to their respective owners in late 1996, once GE's testing was complete.
GE built 106 AC6000CWs for Union Pacific, but with the older, proven 7FDL engine installed, rated for 4,400 hp (3,300 kW). These units were originally intended to be converted to the 6,250 hp (4,660 kW) 7HDL engine after some problems with the 7HDL were solved, but the conversion never occurred. GE calls these units AC6000CW "Convertibles", while UP classifies them as C6044ACs or AC4460CWs.
The AC6000CW ended production in 2001. Union Pacific designates their units as C60AC, CSX as CW60AC and CW60AH.

## Service history

The initial locomotives suffered from various mechanical problems with the most severe being the engine itself. There were major vibration problems which were addressed by increasing the engine mass to lower the resonant frequency. This in turn caused problems with the twin turbochargers. These problems caused GE to push back full production of the new model until 1998. Changes such as stiffer materials and increased engine wall thickness (to increase mass) were in place at full production.
CSX Transportation had re-powered many of their AC6000CW units from 16-7HDL engines to GEVO-16 to make them more reliable and environmentally friendly. These units were capable of 5,800 hp (4,300 kW) but had been rated at 4,600 hp (3,400 kW) and classified as CW46AHs. Union Pacific also had their 16-7HDL AC6000's repowered with FDL-16's, creating an entire fleet of 4,400-hp AC6000CWs.
Beginning in 2018, Union Pacific had begun sending its AC6000CWs to GE for rebuilding. The rebuilt units are classified as C44ACMs. By 2023, all of the units have been rebuilt.
By 2024, CSX had scrapped or sold off all of their AC6000 except for three of their pre-production AC6000CWs that were repowered with FDL16 engines. The rest were either sold off to leasing company Progress Rail Services (PRLX), the Western New York and Pennsylvania Railroad (WNYP), or scrapped.

### World record

On June 21, 2001, all eight of the Australian mining company BHP Billiton's Mount Newman railway AC6000s worked together to set the world record for the heaviest and longest train. They hauled 99,734 tonnes (98,159 long tons; 109,938 short tons) and 682 wagons for 275 kilometres (171 miles) between Yandi mine and Port Hedland. The train was 7.3 kilometres (4.536 miles) long and carried 82,000 tonnes (81,000 long tons; 90,000 short tons) of iron ore. The record still stands as of 2023. These are the only AC6000CWs that were exported outside of the United States. They are the most powerful locomotives to have operated in Australia.

## Operators

| Operator | Type | Roadnumber | Num Built | Build Date | Notes |
| BHP Billiton | Standard | 6070 (Port Hedland) | 8 | June -July 1999 | Wrecked and retired in 2011 |
| BHP Billiton | Standard | 6071 (Chichester) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6072 (Hesta) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6073 (Fortescue) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6074 (Kalgan) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6075 (Newman) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6076 (Mount Goldsworthy) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| BHP Billiton | Standard | 6077 (Nimingarra) | 8 | June -July 1999 | In 2013/14 these were replaced by EMD SD70ACes. Despite their historical significance, they were eventually scrapped in late 2014 after BHP couldn't find any buyers who were interested in acquiring the locomotives. |
| CSX Transportation | Standard | 600-602 | 3 | December 1995 | 600-602 original prime movers replaced with 4,400 hp (3,300 kW) 7FDL16 engines. This is due to these units being pre-production models and mechanical differences between them and the production model. |
| CSX Transportation | Standard | 603-699, 5000-5016 | 114 | October 1998-April 2000 | 603-699, 5000-5016's original prime movers replaced with 4,600 hp (3,400 kW) 16 cyl. GEVO prime movers and new computer equipment essentially making them ES46ACs. CSX classifies these units as CW46AHs. 5015 and 5016 were both classified as a CW60AH. All sold to Progress Rail. 8 units were resold to Western New York & Pennsylvania Railroad; units 6000, 6003, and 6006-6007 later returned to GECX by 2024. |
| Union Pacific | Standard | 7500-7509 | 10 | November 1995-December 1996 | The first ten units were originally numbered 7000-7009. 7000 was the first AC6000CW ever built. All were converted to AC4460CW units and renumbered to 6888-6968. They were classified as C44ACCCA. In 2023, all were rebuilt to C44ACM. |
| Union Pacific | Standard | 7510-7554 | 45 | July-December 1998 | The first ten units were originally numbered 7000-7009. 7000 was the first AC6000CW ever built. All were converted to AC4460CW units and renumbered to 6888-6968. They were classified as C44ACCCA. In 2023, all were rebuilt to C44ACM. |
| Union Pacific | Standard | 7555-7579 | 25 | January 2001 | The first ten units were originally numbered 7000-7009. 7000 was the first AC6000CW ever built. All were converted to AC4460CW units and renumbered to 6888-6968. They were classified as C44ACCCA. In 2023, all were rebuilt to C44ACM. |
| Union Pacific | Convertible | 7336-7405 | 70 | November 1995-September 1996 | These units were renumbered to 7010-7079 to make room for ES44ACs, but are not in the same order. They were classified as C4460AC and rebuilt to C44ACM later on in 2018. |
| Union Pacific | Convertible | 7300-7335 | 36 | March-May 1998 | Classified as C4460AC, all rebuilt to C44ACM in 2017-2018. |

## Preservation

GECX #6002 (ex-Union Pacific #7511) was donated by GE to the Lake Shore Railway Museum in North East, Pennsylvania in 2022. It is the first modern AC traction locomotive to enter preservation.
The Aberdeen Carolina and Western Railway has created their "Engine Room 87" out of the scrapped husk of former PRLX 656/CSX 666 for the US Open special train.