I looked on a couple of previous threads and didn’t really see an answer to this question:
Considering that many roads had/have SD40-2s (or a similar variant) on their roster, would there be a reason to ‘convert’ one to AC? My guess is that a Class 1 probably wouldn’t bother…but maybe a Class 2/regional (or similar entity)? Or would it be cheaper/less headache to simply find a used AC loco and go that route?
My thought is along the lines that the medium HP (~3k HP) range hasn’t seen something like this in a “C” trucked configuration…unless I’m missing something. Yet I know that there are 1500 - 2000 HP AC locos and 4000+ HP AC locos. Or is AC for some reason not feasible in that mid range?
It can be done - But if you are going to replace the electricals, you might as well replace the old 645 diesel as it will not meet the upcoming Tier II emissions regulations. EMD is offering a ‘710ECO’ repower for older engines(both a 2200 hp and a 3200 hp version). UP and KCS are expermenting with several of these ‘repower’ projects currently.
So you’d have an SD32ECO/AC or something similar. Maybe AC32ECO sounds better…wonder how it’d pull and the cost to rebuild an SD40xx into one of these.
The cost means that it just wouldn’t be worth it. Putting AC Drive into a SD40 package, effectively creating a modern SD38-2, and an expensive one at that. The problem is that the locomotive would run out of horsepower before it ran out of tractive effort. Look at how few railroads bought SD38-2s for road service. DM&IR, B&LE, EJ&E, Yankeetown Dock, and that’s about it.
The only North American locomotives that were rebuilt from DC to AC traction were some ex New Haven FL9s rebuilt for Metro North. The cost of this (which included replacing the 16-567 engines) was astronomical. Converting an SD40 to AC traction would be a lot more complex than just changing out the traction motors…
That would be a complete waste of money and resources on locomotive that is past its economic life. Would make more sense to order a new ES44AC and be done with it.
You talking about a 2 Million dollar Rebuild of a lets say Best case a 30 Year old LOCOMOTIVE. You have 30 year old Frame rails Trucks Fuel tanks and other Main componets that sooner or later WILL FAIL. Even the GP-7 and CF-7’s the Santa Fe made are being RETIRED they are way to old and the main steel beams are showing Fatiuge Breaks. Why do Freight cars have a 40 year service life called the matriels can only LAST SO LONG.
Point taken…yet I’ve seen extensively rebuilt GP9s still on Class 1 rails.
I think EMD is on the right track with the 710 ECO rebuild program (and I’m a “GE” guy!). I guess that I thought that a need for the medium HP (~3k) AC loco exists that apparently doesn’t.
EMD’s ECO program is a rebuild in kind except for the diesel itself and the wheelslip control. The word EMD uses is “equity” as in reman traction motors,trucks,frame ,probably sheet metal, radiators,etc. The question asked is converting them to AC traction which mean enough new parts that it wouldn’t cost much more for a complete new locomotive. As far as the diesel is concerned, if the owners will take Tier 0 as good enough then stick with the 645 and the Tier 0 upgrade package. I think that 645’s will last slightly longer than 710’s due to the lower piston speed factor.
For this type of conversion would only the frame and trucks be useable? No frame that has been in any kind of collision would be acceptable. Could the cab be used? AC controls might change a lot in the cab. do we know if the trucks can accept AC traction motors without major modification? Now would the SD-40 frame have attach points compatible for the new equipment? If not even the frames may not be useable. I would believe that it may not be easy to just drill new attach points.Of course an adapter plate might work if it could replace some ballast…
But since the power assemblies are not part of the block in an EMD diesel engine, wear of the cylinder walls is mostly irrelevant. You just keep replacing the liners when you rebuild the power assemblies.
The real question is how intensively are you going to use the rebuilt locomotive. If the monthly mileage will be high enough then the ECO rebuild should pay for itself through greater fuel savings, if not then a rebuild with the upgraded emissions package is probably the way to go.
As for an AC Drive package, it is unlikely that anyone would use the rebuilt locomotives hard enough (miles per month in front-line service) to make that kind of rebuild economical.
The locomotive main frame would suffice, and the truck frames would be ok as well. But all of the sheet metal ahead of the turbo would be gone, the AC electrical cabinet would not fit into the old one, you would need lot of new cooling room for the inverter stacks, for a locomotive that would basically be used in local service for another 10 years? it would be impossible to make it pay. If there was a demand for a 3000 HP AC drive unit, I PROMISE EMD or GE would be exploiting it.