The advent of the new Teir II compliant prime movers got me wondering about the old DD40’s. The horsepower race appears to be over with railroads seeming to prefer the 4000 hp units. I’ve heard the explaination that roads will always use at least two units for reliability so they don’t need the 6000 hp units cause they wouldn’t run them alone and if they needed 12000 hp they would prefer to use three 4000 hp units, more flexibility.
However, I was wondering if it would be feasable to re-power the cold Centennials with the new prime movers and AC traction motors. Some of the new 4000+ hp prime movers are 12 cylinder engines, so size shouldn’t be a problem and the new EMD H series is a 16 cylinder, with 6300 hp, so that should fit. Either way you should end up with enought generation capacity to run the train should one engine fail.
I’m wondering if these engines with their alternator or generators would product too much electricity for eight traction motors to use? In other words, what is the current constraint? The amount of electricity the prime can produce? Or, the amount of electricity the traction motors can effectively and efficiently use?
Any electrical engineer types out there want to chime in?
As cool as that would be to see the DD40AXs re-powered and back on the rails…
If EMD was to build another double-engined locomotive, they would probably design it from scratch instead of using the existing DDs. Of course, we would see the new cab designs utilized. My guess is that if they were to use two engines, it would be a pair of the current 12 cylinder models. This would probably cause for a smaller locomotive than the 96 foot DD40AX. Size is a big issue for flexibility on railroads, and the Class I railroads that would be interested in such a locomotive would probably want to use it on most, if not all, of their rails.
As cool as the DD series are keep in mind that they were basically a concept that failed as it was conceived: The idea was not so much to build a super powerful locomotive as it was to get maintenance savings by having one dual engined unit replace 2 conventional units. In practicality the maintenance savings were never realized and in some cases costs were worse (GE U50 series).
It’s intriguing to imagine a modern DD monster powered by a single huge powerplant (like a 20 cylinder version of the EMD 265H or an 18 cylinder GEVO(GE did build an 18 cyl. HDL stationary test diesel) or CAT 3600-18) but given that the most efficient units for normal RR line haul freight are in the 4300-4400 HP range it wouldn’t seem to be economical.
I’d think that one of the major mainteance problems is that even though it may be one large unit, with two engines, if one axle seizes, you have to remove the entire unit - whereas if it were two coupled locomotives, you simply take the bad one out of service, and the other keeps earning revenue on the line.