A CSX Transportation AC6000CW passing through the New River Gorge, West Virginia in February 2008.

(John Mueller, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons)


GE logo B&W.


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-engine 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.


Union Pacific Railroad 7391, an example of the 106 "Convertibles" built for Union Pacific Railroad with the 7FDL engine.

(terry cantrell, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons)


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 has re-powered many of their AC6000CW units from 16-7HDL engines to GEVO-16 to make them more reliable and environmentally friendly. These units are capable of 5,800 hp (4,300 kW) but are rated at 4,600 hp (3,400 kW) and classified as CW46AH.


BHP Billiton's AC6000CW 6071 at Finucane Island on the Goldsworthy railway, Western Australia in April 2012, an EMD SD70ACe can be seen at right.

(Bahnfrend, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons)


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 109,938 tons (99,734 tonnes; 98,159 long tons) and 682 freight cars for 171 miles (275 km) between Yandi mine and Port Hedland. The train was 4.536 miles (7.3 km) long and carried 90,000 tons (82,000 tonnes; 81,000 long tons) of iron ore. The record still stands as of 2023.



  • BHP Billiton:
  • 8 units, numbered 6070-6077, built in June and July 1999.
    • These are the only AC6000CWs that were exported outside of the United States. They are the most powerful locomotives to have operated in Australia.
    • The 8 units were named after towns and locations in the Pilbara region of Western Australia where they operated.
      • 6070 Port Hedland wrecked and retired in 2011.
      • 6071 Chichester
      • 6072 Hesta
      • 6073 Fortescue
      • 6074 Kalgan
      • 6075 Newman
      • 6076 Mount Goldsworthy
      • 6077 Nimingarra

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:
    • 3 units, numbered 600-602, were built in December 1995.
    • 114 units, numbered 603-699 and 5000-5016, were built between October 1998 and April 2000.
    • 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.
    • 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.
  • Union Pacific:
    • 10 units, numbered 7500-7509, were built between November 1995 and December 1996. These units were originally numbered 7000-7009. 7000 was the first AC600CW ever built.
    • 45 units, numbered 7510-7554, were built between July and December 1998.
    • 25 units, numbered 7555-7579, were built in January 2001.
    • All were converted to AC4460CW units and renumbered to 6888-6968.
  • Union Pacific Convertibles:
    • 70 units, numbered 7336-7405, were built between November 1995 and September 1996. These units were renumbered to 7010-7079 to make room for ES44ACs.
    • 42 units, numbered 7300-7337, 7339, 7340, 7342, and 7344 were built between March and May 1998.

Beginning in 2018, Union Pacific is sending its AC6000CWs to GE for rebuilding. The rebuilt units are classified as C44ACM.


Hood end view of CSX Transportation's 627 at Pinner's Point in Portsmouth, Virginia, note the enlarged radiator section overhanging the rear of the unit.

(William Grimes at English Wikipedia, Public domain, via Wikimedia Commons)



• GECX No. 6002 (ex-Union Pacific No. 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.


GE AC6000CW Overview

Type and origin
Power type: Diesel-electric
Builder: GE Transportation
Model: AC6000CW
Build date: 1995–2001
Total produced: 317
​• AAR C-C
• UIC Co′Co′
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter: 42 in (1,067 mm)
Length: 76 ft 0 in (23.16 m)
Width: 10 ft 3 in (3.12 m)
Height: 16 ft 0 in (4.88 m)
Axle load: 72,000 lb (32,658.7 kilograms; 32.7 tonnes) max
Locomotive weight: 423,000–432,000 lb (192,000–196,000 kilograms)
212–216 tons (189–193 long tons; 192–196 t)
Fuel type: diesel fuel
Fuel capacity: 5,500 US gal (21,000 L; 4,600 imp gal) or 6,200 US gal (23,000 L; 5,200 imp gal)
Prime mover: GE 7FDL16, 7HDL16, GEVO-16 (rebuilds)
RPM range: 200–1,050
Engine type: 45° V16, four-stroke cycle
Aspiration: Twin turbocharger, model 7S1408D
Displacement: 251.2 liters (15,330 cu in) (7HDL16, GEVO-16); 175.2 liters (10,690 cu in) (7FDL16)
Alternator: GE GMG201
Traction motors: GE GEB13 AC
Cylinders: 16
Transmission: diesel electric
AC Alternator to DC link to AC Traction inverters and Motors
MU working: Yes
Locomotive brake: Dynamic and electropneumatic brake
Train brakes: WABCO EPIC 3102 Electropneumatic, others with WABCO 26L pneumatic
Performance figures
Maximum speed: 75 mph (121 km/h) (worn wheels)
Power output: 6,000 hp (4,500 kW)
Tractive effort Starting: 188,000 lbf (840 kN)
Tractive effort Continuous: 166,000 lbf (740 kN) @ 11.6 mph (18.7 km/h)
Factor of adhesion: 2.16 to 2.35
Operators: CSX Transportation, Union Pacific Railroad, BHP Billiton
Locale: North America, Australia
Disposition: Nearly all built have been retired, scrapped, or rebuilt as C44ACM. GECX 6002 (formerly Union Pacific 7511) preserved at the Lake Shore Railway Museum in North East, Pennsylvania.