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A CSX Transportation AC6000CW passing through the New River Gorge, West Virginia in February 2008
Type and origin
Power typeDiesel-electric
BuilderGE Transportation
Build date1995–2001
Total produced317
 • UICCo′Co′
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Wheel diameter42 in (1,067 mm)
Length76 ft 0 in (23.16 m)
Width10 ft 3 in (3.12 m)
Height16 ft 0 in (4.88 m)
Axle load72,000 lb (32,658.7 kilograms; 32.7 tonnes) max
Loco weight423,000–432,000 lb (192,000–196,000 kilograms)
212–216 short tons (189–193 long tons; 192–196 t)
Fuel typediesel fuel
Fuel capacity5,500 US gal (21,000 L; 4,600 imp gal) or 6,200 US gal (23,000 L; 5,200 imp gal)
Prime moverGE 7FDL16, 7HDL16, GEVO-16 (rebuilds)
RPM range200–1,050
Engine type45° V16, four-stroke cycle
AspirationTwin turbocharger, model 7S1408D
Displacement251.2 liters (15,330 cu in) (7HDL16, GEVO-16)[1]
175.2 liters (10,690 cu in) (7FDL16)[2]
AlternatorGE GMG201
Traction motorsGE GEB13 AC
Transmissiondiesel electric
AC Alternator to DC link to AC Traction inverters and Motors
MU workingYes
Loco brakeDynamic and electropneumatic brake
Train brakesWABCO EPIC 3102 Electropneumatic, others with WABCO 26L pneumatic
Performance figures
Maximum speed75 mph (121 km/h) (worn wheels)
Power output6,000 hp (4,500 kW)
Tractive effortStarting: 188,000 lbf (840 kN)
Continuous: 166,000 lbf (740 kN) @ 11.6 mph (18.7 km/h)
Factor of adh.2.16 to 2.35
OperatorsCSX Transportation
Union Pacific Railroad
BHP Billiton
LocaleNorth America, Australia
DispositionNearly 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, one converted to a bar by Aberdeen, Carolina and Western Railway.

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.[3]

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.[3] 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.[3] 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

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

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.

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

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.[4] The record still stands as of 2023.


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
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

In 2013/14 these were replaced by EMD SD70ACes.[7] 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.[8]

  • 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. All sold to Progress Rail
    • 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.


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.[9]

See also


  1. ^ Official archived engine description
  2. ^ 7FDL16 Specifications Page 24
  3. ^ a b c McDonnell, Greg (2002). Field guide to modern diesel locomotives. Waukesha, Wisc.: Kalmbach Publishing. pp. 74–77. ISBN 0-89024-607-6. OCLC 50411517.
  4. ^ BHP breaks its own 'heaviest train' record Archived 7 January 2016 at the Wayback Machine Railway Gazette 1 August 2001
  5. ^ "BHP AC6000". Railpage. Retrieved 22 February 2019.
  6. ^ Clark, Peter (2012). An Australian Locomotive Guide. Rosenberg Publishing. p. 288. ISBN 9781921719554.
  7. ^ "BHPB Iron Ore Update" Motive Power Issue 91 January/February 2014 page 9
  8. ^ "10-2014 - Pilbara Railways Scanned and Digital Image Showcase". Retrieved 22 February 2019.
  9. ^ "Wabtec donates AC6000 locomotive to Lake Shore museum". Trains. 23 March 2022. Retrieved 23 March 2022.