Yes it’s true, EMD is building SD80ACes, though the current batch is for export only. I wonder what the SD80ACe’s hp rating is since the SD80MAC was 5,000hp.
And I heard on another forum that these SD80ACes are only tier-1 compliant, which if true means EMD would have to do modifications to make a tier-3 SD80ACe. IMO, I doubt any north American class 1s would buy the 20-710 SD80ACe since they’re content with 16 cylinder EMD and 12 cylinder GEs and are acquiring more of them, even though both NS and CSX roster a handful of SD80MACs.
Its tier 1 for two reasons: a. its going to Australia and B. With judicious tuning they can maximize the fuel efficiency if they don’t have to worry about the NOx emissions. Thermodynamic efficiency is determined between the maximum cycle temperature and the minimum. To reduce NOx everybody has to reduce the maximum temperature by several different methods. If you remember that an EMD engine is 20 or 16 one cylinder engine connected by a common crankshaft mounted in a suitable frame. The only problem might be tweaking the turbocharger. So for domestic use the V20 710 is or will be tier 3.
The SD80ACe’s were sold to Vale do Rio Doce, the Brazilian mining concern. Are they being assigned to EF Carajas (5’3" gauge) or EF Vitoria a Minas (meter gauge)?
On December 22nd Progress/Caterpillar moved three more Vale SD80ACe’s from the plant, this time not on flat cars, but on temporary trucks to Stratford, ON for storage. Included in this move were primer coated Vale C-322-4 (104 - anti-climber chalked C322-4; but nose marked 5E); C322-5 (105 - anti-climber chalked C322-5; but nose marked 4E) on their own trucks, and C322-7E (107) on KRL flat 70989.
SD80ACe spotting features:
The engine room has 10 doors (8 on SD70ACe) - one per cylinder per side of the engine (total of 2o cylinders/engine room doors).
The radiator wings are larger as well - there are 9 doors under the radiators on the SD80ACe, 8 on an SD70ACe and hree radiator fans instead of two on the SD70ACe.
I’ve read that theses units are rated at 5,500HP,however that may be Gross Engine power rather than the Net power rating commonly used in North America…
Good question, but I hope not! If a 16-710 can do about 4500 BHP at 900 RPM, then the 20-710 should be good for 5400 or so THP.
I remember talking to the EMD engineers when Conrail was getting the SD80MACs and asking if a 5500 THP rating, that would give them the same per cylinder output as the SD75s they were building for the ATSF, was possible in the future. I got a “probably”.
Horsepower is pretty much irrelevant when talking about locomotives since it is turning a generator. Tractive effort is what defines a locomotive. You can have the same engine and change wheel sizes, traction motors, generators, and gear ratios and get a wide variety of traction effort ranges. Also upgrading the electrical from DC to AC will give you a big increase in tractive effort.
Many boats do use the same engines as locomotives especially the 645. Horsepower is totally relevant when talking about a boat engine since it is not turning a generator and is constant with its applications.
No. HP is completely relevant. A locomotive is a constant HP machine above minimum continuous speed. In fact, HP = TE x speed/308 (plus or minus a bit)
Don, or any other railroad people, can you explain to me Minimum Continuous Speed (MCS)?
My understanding is that the tractive effort is almost directly proportional to traction motor current, and this is true both for AC and DC? And traction motor current makes heat that seeks to destroy insulation and motor windings, were it not for the traction motor blowers trying to dissipate that heat? And the Maximum Continuous Tractive Effort (MCT) is determined by those considerations.
Suppose a locomotive was lugging up a hill at its MCT (max tractive effort without going into short-time rating) and at its MCS (minimum continuous speed) with the throttle in Notch 8. Suppose it started to slow down from MCS owing to some increase in gradient or train resistance. On a modern unit, would not the microprocessor engage horsepower limiting so the locomotive would continue to deliver its MCT below the minimum continuous speed (MCS), or in the absence of the microprocessor module, could not the engineer watch the ammeter and make a throttle reduction that would hold tractive effort at MCT while slowing down?
You are correct for a series wound DC motored locomotive. With an asynchronous 3-phase AC induction motor locomotive, Motor torque is a function of traction motor slip. An AC locomotive can maintain maximum TE from near zero speed until either maximum applied voltage or maximum supplied power frequency is reached. Once either one of these factors cannot increase then AC motor speed cannot increase without a decrease in motor torque.
I have no idea where you got that calculation. According to Wikipedia…“For an electric locomotive or a Diesel-electric locomotive, starting tractive effort can be calculated from the amount of weight on the driving wheels (which may be less than the total locomotive weight in some cases), combined stall torque of the traction motors, the gear ratio between the traction motors and axles, and driving wheel diameter”…
A GP38-2 has the same 16 cylinder engine as a SD40-2. There is no difference at all with the horsepower coming out of the engine driving the generator. Yet a GP38-2 has considerably less tractive effort than a SD40-2 because of the obvious reason of weight of the locomotive and two more axles and two more traction motors.
So going to my point earlier putting a 645 engine or even a modern 710 engine into a GP40-2, GP38-2, GP40, GP15, or other GM locomotive that
The HP = TE x speed/308 applies when the locomotive is operating above the speed where the prime mover can supply enough power to supply maximum continuous tractive effort. This speed is higher for a GP40-2 than it is for an SD40-2, due to the lower CTE on the GP40-2. By 20 MPH, the maximum tractive effort for the GP40-2 and SD40-2 will be the same as the tractive effort is horsepower limited as opposed to adhesion or thermally limited.
The formula for a 100% efficient transmission is HP = TE x speed/375 or TE = HP x 375/speed. The 308 figure comes from assuming an 82% efficiency for the electric transmission.
Erik where you are getting this information is puzzling. The tractive effort of a GP40-2 is never anywhere near what a SD40-2 can produce at any speed. The SD40-2 has a minimum tractive effort of 82,100 and a maximum of 92,000. A GP40-2 has a minimum tractive effort of 54,700 and a maximum of 61,000. Both have EMD 16 cylinder 645E3 engines rated at the same horsepower.
Second as a former locomotive mechanic I can tell you the locomotives engine produces more than enough horsepower to turn the generator at any speed or load. If you look at the technical details you will notice the locomotive has a constant RPM speed at every notch that varies little regardless if it is under load or not. That is why the 645 engine is in nearly all EMD locomotives that required a 16 cylinder engine starting in the mid 1960’s up until the 710 engine came along around the mid 1980’s. Even with the 710 engine it is nearly identical to the 645 in every aspect except for 710 cubic inches per cylinder instead of 645 cubic inches.
The limitations in tractive effort have had little to do with the horsepower of the engine and a lot to do with how much of a load a traction motor could handle before burning up. With AC technology they have eliminated the problems of burning up a traction motor but are still stuck with the size they can build a traction motor and fit it under the trucks.
The tractive-effort-related limitations on AC-traction locomotives are (1) the ability of the wheels to maintain adhesion at high levels of wheel torque and (2) the levels of mechanical stress that occur when those high levels of wheel torque are produced. At the very low speeds where those levels of torque are most likely to be produced, tractive effort does depend on adhesion, not on horsepower. However adhesion is a function of the regulation of wheel creep. The slower a wheel is rotating, the greater the difficulty of regulating its creep and the greater the risk of stalling if creep is not adequately regulated. Horsepower is relevant, in that context, because an increase in horsepower allows a higher level of tractive effort to be produced for any given speed above the adhesion-limited speed range. Consequently if a locomotive needs to produce a given level of tractive effort to move its train, it is advantageous for the locomotive to be able to produce that level of tractive effort at speeds above the adhesion-limited low speed range.
