So this has been bugging me maybe its been answered before... Why was the ac4400cw offered but not the ac6000cw as a DLC option for Sand Patch grade? This keeps me up at night thinking about it. :/
The hard part about the GE locomotives is that they are all pretty much the same from the North American Cab Dash-8s through the AC6000CW, with a few changes to the body.
So its not so much look as it is power why run 3 to 4 gp38's when 2 ac6000's can do the job easier and faster too
If Im being completely honest id love to see the DDA40X for sand patch but well never see that one :'(
In reality, if one of those locos fail, then you are down 6000hp vs 4400 with modern locomotives, saw on a Pentrex video of one that failed on a BNSF train on Tehachapi Pass, and a UP train had to go rescue it cause it couldn't make the grade with the loss of power. I also don't think any are around in their original configuration anymore. CSX had 3 delivered with 4400hp Prime movers, and the rest have been rebuilt with 4600hp prime movers and reclassified as CW46AH's, some have also been sold to Progress rail now...
The AC6000CWs were designed to haul heavy coal trains where the AC4400CWs could not. However, the idea of more horsepower didn't work. I could get into the detailed physics of it, but you probably don't want to hear that, so I'll sum it up. With the much higher horsepower, the AC6000CWs couldn't maintain tractive force at low speeds causing the trains to stall. So they were mostly assigned to fast intermodal trains on the Boston Line. The solution to the remaining problem with stalling coal trains was solved by adding a few hundred pounds of ballast to AC4400CWs. this allowed them to maintain tractive effort at speeds as low as 2 mph, reducing the chance of stalling. This is why CSX also owns two models of the ES44, the ES44AC and ES44AH (h for heavy). All of CSX's new GE Tier 4 units are heavy units, hence the model name ET44AH. CSX also ordered heavy SD70ACes, but was ultimately displeased with the units and sold them to Progress Rail. Yes, CSX had rebuilt some, but not all of they're AC6000CWs with 4600hp prime movers, and later many de-rated again to 4400hp. However, I don't think any are on the roster anymore to help save costs on servicing, because they require some special parts that make them an oddball in the servicing shops. Most are currently in storage with leasing companies (as well as all of CSX C40-8Ws). Last year, the shortline railroad Western New York & Pennsylvania bought 6 AC6000CWs from Progress Rail to support their aging fleet of MLW and Alco units.
Well right now there are practically no more AC6000s around to gather details from a research trip by DTG anymore so that’s probably why DTG skipped the loco and went for the AC4400. Like others said here the locos were designed for heavy coal trains but the failure of traction control swapped them over to intermodal and other light and fast services. Also, in real life the locomotives were a failure since an engine producing that much power overheated quickly and too much, and more maintenance was required than average which kept them in the shops rather than on the tracks, a big loss for CSX as they’re just focusing on maintenance costs and keeping the locos in storage rather than investing on improving other factors of the railroad such as newer locos and more, better safety systems/more modern infrastructure (signaling, PTC, etc.). So it would be a great loco for TSW because of the Horsepower, but known to rail fans as one of the biggest locomotive failures in history, and the lack of models for research most likely made DTG scratch if off the list, but hey, they could do the successor of the locos such as the CW46AC or the ES44s in the future, but anyways DTG is already planning the Dash 8 for sand patch, and I don’t know what other dlc could be coming after that one for this route, or if there is even any more dlc being planned.
One thing to keep in mind's that the 4400's way more common, if you're going to make just one or the other it's a no brainer. The 6000 while fairly common in comparison to other oddities like the DD40X & Gas Turbines still weren't produced in massive numbers. As for why they haven't made it as a add on I think it's two fold. 1: There's minor differences but at the end of the day they're pretty much the same shell with different engines, it's not that new of a experience so it would have fairly limited appeal. 2: You'd have to give it new services, sure you technically could have it just swap in, but in order to truly show the power you'd have to slot in bigger freight trains. The C40-8W kind of shows this, it's a bit more different from the 4400 with the classic style cab, and I imagine can just slot in with existing services quite easily with the given the similar horsepower, so don't need to muck around with the timetable.
