Porterbrook Leasing started to lease a total of 20 loco´s to European operators like HGK, ShortLines, Rail4Chem, DLC Railway and ERS Railways. This was soon followed by orders from several other operators and leasing companies, which resulted in more than 60 loco´s in Europe nowadays. 

Also Poland got their first 66s in 2007.

• EMD Classification: JT42CWR - "Class 66"
• Built At: General Motors/EMD - London, Ontario (Canada)
• Wheel Arrangement: CO–CO
• Engine: General Motors 12N-710G3B-EC : 2.462 kW (3.300 HP) at 904 rpm
• Traction Alternator: General Motors AR8PHEH
• Auxiliary Alternator: General Motors CA6B
• Traction Motors: General Motors D43TR Axle Hung (6x)
• Power At Rail: 2.240 kW (3.000 HP) 
  Trucks: HTCR-E
• Wheel Diameter: 1,067 m.
• Sanding Equipment: 8 x 42,5 litre carbody mounted sand boxes with air delivery (50 kg per box)
• Gear Ratio: 81:20 (except for Freightliner 66/6: 83:18)
• Maximum Speed: 120 kmh (except for Freightliner 66/6: 74.7 kmh)
• Maximum Tractive Effort: 409 kN (except for Freightliner 66/6: 467 kN)
• Continuous Tractive Effort: 260 kN at 25.6 km/h (except for Freightliner 66/6: 296 kN at 22.5 kmh)
• Length: 21,35 m.
• Width: 2,64 m.
• Height: 3,91 m.
• Maximum Weight: 126.000 kg.
• Brake System: Westinghouse PBL3 Air Brake
• Brake Force: 68.000 kg.
• Fuel Capacity: 6.550 lit.
• Minimum Curve: 80 m. (radius)
• Multiple Working: JT26CW-SS (Class 59) , JT42CWR (Class 66) , JT42HW-HS (Class 67) 

CD 66-lokomotivet (EMD-klassifisering JT42CWR) er en redesignet versjon av British Rail Class 59 (EMD-klassifisering JT26CWSS). 
British Rail Class 59 har vært i drift i Storbritannia siden 1986.

Suksessen til Class 66 nådde også land utenfor Storbritannia. 
Den tyske operatøren HGK (Hafen und Güterverkehr Köln) bestilte 2 lokomotiver som ble levert i 1999. 
I Skandinavia har lokomotivtypen vært i drift for blant annet TGOJ Trafik (Sverige) og CargoNet (Norge).

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