Since November 4, 2011, CSX ES44AC 954 has been in captive service out of Grafton, West Virginia testing a variety of advanced adhesion control systems.
The determinate on locomotives is the effectiveness of the wheel/rail interface and it's ability to keep wheels moving without slipping.
With the current state of the wheel slip art - the locomotives we have today have maxed out today's technology. To be able to transmit more horsepower and toque to locomotive wheels, there needs to be another breakthrough beyond the AC traction we presently have.
Unless and until there is a wheel slip breakthrough we will continue to see the size and horsepower of the locomotives that are currently being built - just cleaner and greener.
Never too old to have a happy childhood!
For locomotives, to haul tonnage you need tractive effort. To haul tonnage at speed, you need horsepower. As such, the 6000 HP locomotives were primarily intended to be operated on intermodal and fast freight services. Unfortunately, the reliability hurdle was not overcome and the prospects of losing half of the power on a Z train versus one third made them impractical for their intended service. 4000 HP locomotives are more flexible.
As Leo notes, once the 6000 HP locomotives failed, the horsepower race was over and the emissions race started. I think that this will continue for the next several years at least as it is unlikely that all the bugs will be worked out in the Tier IV locomotives at release. Beyond that, it is difficult to tell. Based on operational problems, I don't think we will see much more horsepower growth as it doesn't make much operational sense.
If memory serves, the ES58ACi and SD80ACe were both Tier II compliant, but not Tier III. South American mining railroads use them to move heavy trains at higher speeds where capacity is tight.
That doesn't necessarily mean that we're going to remain at this horsepower plateau. Witness the brief popularity of 3,600 horsepower models before the industry universally returned to the 3,000 HP standard and stayed there for quite a while.
I suspect we'll see this start growing upwards again one of these days. After a brief but essentially unsuccessful fling with 6,000 HP machines (And 5,000 HP SD80MAC's on Conrail), EMD and GE have been too preoccupied this century with adapting their existing product lines to ever more stringent emission standards, riding out economic troubles, moving/shifting their manufacturing centers, and EMD's various sales to mess around with this.
Once things stabilize for a while, I suspect we'll see a return to the horsepower race. The single biggest thing holding them back is reliability. They were spending too much time in the shop and were creating operational issues.
Where as a intermodal train for instance might keep moving reasonably well if one of its three locomotives go down, it's much less likely when you're losing half your power.
Build a reliable 6,000 HP machine and get a major customer to give you a chance to prove your stuff, and sales will come.
They have produced Tier 3 compatible versions of both those locomotives.
Nobody bought them in the USA.
There are ES59ACi units and SD80ACe units working in Brazil.
If UP or BNSF wanted them they would have bought them.
They didn't.
M636C
Since Ferrari, and Porsche are creating super cars that run on electricity, it got me thinking why havent the GE or EMD created Tier 4 versions of AC6000s and SD80macs?
Please ask if I need to clarify.
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