Downer EDI Rail GT46C ACe
The first units were built as the SCT class for freight operator SCT Logistics from 2007 followed by the WDG class in India, TLD class for Downer Rail's Locomotive Demand Power division, the TT class for Pacific National, the GWA class for Genesee & Wyoming Australia, the WH class for Whitehaven Coal, and the SSR class for Southern Shorthaul Railroad.
The class was a new design for Australian conditions based on other locomotives produced by Downer EDI Rail, such as the narrow gauge GT42CU AC purchased by Queensland Rail and Pacific National and the GT46C purchased by Westrail, Freight Australia and FreightLink. The GT42CU AC used a 12-cylinder EMD 710 engine, based on the USA built SD70MAC with scaled down traction motors, while the GT46C used a 16-cylinder EMD 710 engine with DC traction systems. The American SD70ACe was EMD's 2nd generation AC loco with IGBT inverters, but was too large and heavy for the Australian interstate standard gauge network, weighing in at 188 tonnes when the limit was 134 tonnes. In addition, the GT46C design was already at the 134 tonne limit, even before adding inverters, heavier traction motors and more cooling capacity for higher power engine, and there was a requirement that fuel capacity could not be sacrificed.
The locomotive has AC traction equipment, with a Mitsubishi Electric package also used on the SD70ACe, including a TA17 traction alternator, CA9E companion alternator and six ITB 2630 traction motors, along with solid state IGBT inverters. The prime mover is a turbocharged 16-cylinder EMD 710. New technology used included passive steer bogies, to reduce flange wear on corners. The class were built at Cardiff, with the frames constructed at Port Augusta, and the bogie frames at Kelso, reliability was instilled in this class through the tireless efforts of Darrell Sherry, and the tight document control of Rob McNulty. The Downer Rail GT46C ACe and the PL class are the only locomotives to bear Rob's personal stamp of approval.
The SCT class are used by SCT Logistics on their freight services from Adelaide to Melbourne, Parkes and Perth. Locomotive SCT007 is named Geoff (James Bond) Smith after the CEO of the company. The benefits of AC traction has enabled a fleet of 15 locomotive to do the work of 20 DC traction equipped locomotives, three AC vs four DC units being needed on the Melbourne to Adelaide journey, and two AC vs three DC units between Adelaide to Perth. An on-train refuelling system carries 60,000 litres of diesel in a tanker behind the locomotives and eliminates the need to refuel en route.
The LDP class were built by Downer EDI Rail to be leased out to rail operators through their subsidiary Locomotive Demand Power. In December 2008 it was announced that QR National has signed a five-year deal for the nine locomotives, covering the construction and delivery of the locomotives, maintenance, the provision of spare parts, and options to extend the lease for an additional five years. They are used on standard gauge intermodal freight services, LDP001-003 were painted in a blue and white Downer EDI Rail livery, while the remainder are in QR National yellow livery. A further five were manufactured in 2013.
With the aging of the 48 and PL-class fleets, Pacific National purchased 31 TT classes for the trains of the Hunter Valley. TT01 was later named "Darrell Sherry". They are equipped with ECP brakes and are used with NHDH, NHEH and NHYH hopper compartments equipped with Bradken Rail.  They are different in some respects from SCT / LDP category units because they can run at two different weights: their weight, fuel load and operating range when the weight is between 139 and 132 tons Heavyweight same 90 classes; but under 132 tons, they are cleared for normal operation, such as SCT / LDP class.  
The first locomotives were originally intended to built as LDP010-LDP018, and leased to other railway operators, until Downer EDI and Pacific National reached an agreement to sell directly.  TT01 conducted the first test on November 26, 2009.
TT130, TT131 and TT132 are owned by UGL
The three WH class locomotives were ordered by Whitehaven Coal entering service painted blue and white. They are used to haul coal trains from Whitehaven's mines in the Gunnedah Basin and are operated by Pacific National.
The 2 class members were ordered by Southern Shorthaul Railroad in 2014 to operate its grain services, displacing hired motive power.
|Owner||Class||Number in class||Road numbers||Built||Notes|
|SCT Logistics||SCT class||15||SCT001-SCT015||2007-08|
|Downer Rail Locomotive Demand Power||LDP class||9||LDP001-LDP009||2009-10||LDP001-LDP009 leased to Aurizon. LDP010-LDP012 sold to Pacific National to become TT130-TT132, April 2015. LDP013-LDP014 sold to Southern Shorthaul Railroad to become SSR101-SSR102.|
|Pacific National||TT class||40||TT01-TT08, TT101-TT132||2009-12||TT130-TT132, ex-LDP010-LDP012.|
|Whitehaven Coal||WH class||3||WH001-WH003||2011||Operated by Pacific National|
|Genesee & Wyoming Australia||GWA class||10||GWA001-GWA010||2011-12|
|Southern Shorthaul Railroad||SSR class||2||SSR101-SSR102||2014||SSR101 is named "Enfield" and SSR102 is named "Bendigo". ex-LDP013-LDP014.|
- Downer EDI Rail GT46C, ancestor model
- Downer EDI Rail GT42CU AC, narrow gauge variant
- Downer EDI Rail GT42CU ACe, narrow gauge gauge variant
- UGL Rail C44aci, principal competitor
- Paul-Hewison. "Introducing the next generation locomotive to the Australian rail network" (PDF). Presentation, Conference on Railway Engineering 2008. www.core2008.org. Archived from the original (PDF) on 13 September 2009. Retrieved 2009-09-05.
- "Downer EDI factsheet: GT46C ACe" (PDF). www.downeredi.com. Retrieved 2009-09-05.
- Motive Power team (April 2008). "The SCT Class - A Brief Look". Motive Power: 56–57.
- SCT Class Vicsig
- "Innovation is the locomotive". The Age. www.theage.com.au. 6 June 2005. Retrieved 2009-09-05.
- "Downer Edi Secures $45 Million Locomotives Deal With QR". Downer EDI media release. www.downeredi.com. 11 December 2008. Retrieved 2009-09-05.
- "QR signs $45 million locomotive leasing agreement with Downer EDI". QR Media Centre. www.media.qr.com.au. 11 December 2008. Retrieved 2009-09-05.
- "EDI: LDP Class". Locopage. locopage.railpage.org.au. Retrieved 2009-09-05.
- LDP Class Vicsig
- WH Class Vicsig
- Genesee & Wyoming Australia commission first of 16 locomotives Adelaide Advertiser 22 November 2011
- New locos to upgrade and expand Genesee & Wyoming fleet Rail Express 23 November 2011
- GWA Class Vicsig
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