How much more efficient are modern diesel locomotives compared to their first generation counterparts?
Vastly, with the advantages of EFI and more broadly FADEC being examples.
On the other hand 'progress is not always forward' most particularly with respect to pollution control, where fuel efficiency in particular can take remarkable hits and maintenance cost can metastasize.
As I have noted, it would not be difficult to make diesel prime movers much more thermodynamically efficient with better regulatory common sense combined with adoption of larger-mass-flow SCR.
I'd wonder if some improvement could come from turbo-compounding, with the turbine(s) driving an alternator(s). The electronics associated with the alternator would impose the optimal load on the turbine, with the electric power put on the same bus as the main alternator. The induction compressors would also derive power from the bus, allowing for faster spool up.
Erik_MagI'd wonder if some improvement could come from turbo-compounding, with the turbine(s) driving an alternator(s). The electronics associated with the alternator would impose the optimal load on the turbine, with the electric power put on the same bus as the main alternator. The induction compressors would also derive power from the bus, allowing for faster spool up.
I believe F1 is using similar tactics with their turbocharged hybrid gas engines, which have 'motor generators' that are driven by heat (MGU-H) and kenitic (MGU-K) energy. The total package of 1.6L engine displacement is reported to put out over 1000 HP from both ICE and Electrical outputs.
Never too old to have a happy childhood!
Last month on my way to our 15th Cotton Belt Regional Railroad Symposium I encountered four southbound Union Pacific trains between Brinkley and Pine Bluff. Three were parked on the mainline with their crews staring at red blocks. The fourth was walking its train over the Arkansas River Bridge and into Pine Bluff Yard. It doesn't matter how a locomotive is built if it is standing still. Later at the Arkansas Railroad Museum a retired SSW/SP/UP hoghead told me that as long as the trains are parked it was considered running time and not dwell time.
Ed in Kentucky
I'll guess 20-25%.
Al Krug's table is available on the Wayback Machine -- it says an F7 or SW1500 burned 93 gallons per hour in Run 8.
https://web.archive.org/web/20100529204212/http://www.alkrug.vcn.com/home.html
SSW9389Last month on my way to our 15th Cotton Belt Regional Railroad Symposium I encountered four southbound Union Pacific trains between Brinkley and Pine Bluff. Three were parked on the mainline with their crews staring at red blocks. The fourth was walking its train over the Arkansas River Bridge and into Pine Bluff Yard. It doesn't matter how a locomotive is built if it is standing still. Later at the Arkansas Railroad Museum a retired SSW/SP/UP hoghead told me that as long as the trains are parked it was considered running time and not dwell time. Ed in Kentucky
I don't know UP rules concerning stopped trains on the Main Line.
On CSX when I was working, trains were to be advised if they were going to be stopped for 30 minutes or more. Crews were to shut down all engines except for the lead engine for fuel conservation. Crews were to be given adequate notice of when they were going to be moving again so they could get the shut down engines running and on line again - nominally about 10 minutes per unit (note - with 21st Century AC road locomotives - on CSX it was rare to have more than 3 units on line account head end horsepower restrictions.) CSX didn't begin to utilize DPU's until after I retired, so I am not aware of how they are handling them.
Sitting in sidings or being held out of terminals is considered line of road delay, not terminal dwell. When it comes to operating statistics there is always a 'game' being played between terminal management and line of road management, the game started once it was understood there were terminals and line of road.
BaltACDOn CSX when I was working, trains were to be advised if they were going to be stopped for 30 minutes or more. Crews were to shut down all engines except for the lead engine for fuel conservation.
That's exactly what I'd see when I was doing some lunch-hour or slow-day railfanning at a favorite spot near the Richmond Amtrak station. (Old RF&P, now CSX)
Typically a diesel lash-up of three or four units stopped and waiting, the lead unit running but the trailing ones shut down. It was pretty interesting to catch the start-ups too.
timz I'll guess 20-25%. Al Krug's table is available on the Wayback Machine -- it says an F7 or SW1500 burned 93 gallons per hour in Run 8. https://web.archive.org/web/20100529204212/http://www.alkrug.vcn.com/home.html
For context, the C44-9 burns 210 Gal/Hr so in a one-dimentional view, not an improvement.
If you look at the HP per Gal/Hr, it tells a better story. From the low of an E-8 at 12 HP/Gal/Hr to the C44-9 (about the newest locomotive with data on Al's page) at 20.9 HP/Gal/Hr a definite improvement over the years.
The only real measure that the carriers look at it ton miles/gallon. In territories where 1st Gen locomotives were rated at 1000 tons, today's locomotives are rated North of 5000 tons per unit.
It would be interesting to see the overall fuel usage and efficiency figures on the variable horsepower Cv40-9i's (NR class) introduced by National Rail in Australia.
CSSHEGEWISCH It would be interesting to see the overall fuel usage and efficiency figures on the variable horsepower Cv40-9i's (NR class) introduced by National Rail in Australia.
What this does NOT do is control the engine governors in a consist to achieve the equivalent of restricted notch or excitation. Instead it acts to keep some locomotives in the consist at high notch while near-idling the rest (see SmartConsist or Smart HPT) which is not what the three-stage derating system on the NDs apparently does.
What makes newer locomotives more efficient, by far, are AC traction motors and computerized wheelslip technology.
See for example
https://repositorio.itl.org.br/jspui/bitstream/123456789/367/3/Reducing%20variability%20in%20train%20operation%20to%20improve%20fuel%20efficiency.pdf
I would say from my experience at EMD it was continuous improvement in engine BSFC starting at about 0.4 lb/BHP-Hour for the roots blown 567 to close to 0.31 for a turbocharged 710, coupled with an ongoing pursuit of reducing parasitic accessory load of cooling fans and traction motor and generator blowers via multi-speed motors and lately variable speed drives. Larger radiators with more tubes and separate aftercooling allowed reduced fan HP and more efficient engine operation.
Probably valuable to add that the SFC improvements would have been far more dramatic if pollution control were not also a concern. One of the great advances was proportional EFI capable of multiple/pilot injection; another was eliminating the mechanical drag of the positive-displacement Roots blower at high engine rpm.
I think 20-25% isa on the low side. I'll have to do some digging.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Close to 50% from 1965 to 2015 according to Michael Iden's presentation to Railtech: http://railtec.illinois.edu/wp/wp-content/uploads/pdf-archive/9.1.pdf
1965 corresponds very well with the start of mass deliveries of EMD's 645-powered 2nd generation locomotives.
Better watch out, though: Iden also includes a discussion of platooning (with favor) and considered the Arrowedge to be innovative out-of-the-box thinking (I consider it more out-of-their-minds thinking as things turned out...)
What is highly interesting is the virtual collapse of gallon-per-ton-mile consumption in the relevant graph (note the interesting little pip centered circa 1985) which really ought to be redrawn at much larger vertical scale with a commented timeline... hmmm, that might be the basis for a good Trains article.
Absent is a discussion of advances (and shortfalls!) in actual engine technology and pollution-control equipment. While that might induce MEGO syndrome in conference attendees just as it does in forum posts, it would have been interesting to touch on.
As would the relative worthlessness of 'notch restriction' in actually conserving gal/ton-mile, or the actual big saving from running those PSR monstrains... interesting things have happened since ~2015.
ns145Close to 50% from 1965 to 2015 according to Michael Iden's presentation to Railtech: http://railtec.illinois.edu/wp/wp-content/uploads/pdf-archive/9.1.pdf
timz ns145 Close to 50% from 1965 to 2015 according to Michael Iden's presentation to Railtech: http://railtec.illinois.edu/wp/wp-content/uploads/pdf-archive/9.1.pdf That says nothing about the efficiency of the locomotive -- just the "efficiency" of the average train, based on ton-miles. The locomotive's SFC hasn't decreased by 50%.
ns145 Close to 50% from 1965 to 2015 according to Michael Iden's presentation to Railtech: http://railtec.illinois.edu/wp/wp-content/uploads/pdf-archive/9.1.pdf
That says nothing about the efficiency of the locomotive -- just the "efficiency" of the average train, based on ton-miles. The locomotive's SFC hasn't decreased by 50%.
The presentation has everything to do with changes in the overall fuel efficiency of locomotives. I grant you, however, that it doesn't contain specific data on changes in the fuel efficiency of locomotive diesel prime movers.
ns145The presentation has everything to do with changes in the overall fuel efficiency of locomotives.
timz ns145 The presentation has everything to do with changes in the overall fuel efficiency of locomotives. "Overall fuel efficiency" meaning ton-miles per gallon of fuel. The report says nothing about horsepower-hours per gallon of fuel -- they couldn't measure that, of course. Apparently the average ton-mile is easier to produce now, because the locomotive's SFC (drawbar horsepower divided by fuel burn per hour) hasn't dropped by "close to 50%".
ns145 The presentation has everything to do with changes in the overall fuel efficiency of locomotives.
"Overall fuel efficiency" meaning ton-miles per gallon of fuel. The report says nothing about horsepower-hours per gallon of fuel -- they couldn't measure that, of course. Apparently the average ton-mile is easier to produce now, because the locomotive's SFC (drawbar horsepower divided by fuel burn per hour) hasn't dropped by "close to 50%".
Work performed by unit of fuel is the only way for railroads to effectively measure economic fuel consumption.
Railroads don't measure how much fuel it takes to run light power down to the corner store for a gallon of milk and a pack of gum.
Before you get too far carried away with semantics, the thread is about locomotive prime-mover efficiency, not horsepower per ton mile, which implicitly includes train speed. If you were to extend Iden's graph past 2015 I don't doubt you would see "improvements" in fuel consumption due to the new drag era of slower, longer trains, just as you see some of his anticipated gains from systems like LEADER and TO, or expanded use of distributed power.
That only incidentally involves higher efficiency in the diesel prime movers: for that, you'd need to invoke things like variable-vane or staged turbos, better EFI and what used to be called FADEC, better tribology and ring/bore friction reduction... and on the negative side, efficiency reductions related to such details as idiot EGR and DPFs that are 'cleaned' regeneratively.
I'm sure there will be papers in SAE somewhere about post-2012 discussions of heavy diesel combustion-engine efficiency.
OM, I understand what you're saying, but at some point one would also have to consider the effect of other design changes to locomotives outside the prime mover on overall efficiency. Current EMD/GE models, thanks to advances in wheel slip control, adhesion, and AC traction motors can get much more of the electrical current they generate to the rail to move tonnage. Early 2nd generation models, such as the SD45 and GP40, had to derate themselves at maximum load at low speeds to avoid massive wheel slip. I'm sure that early 1st generation models had even lower adhesion values and more primitive wheel slip controls. Somehow all of this should get factored in, albeit with apples-to-apples comparsions between similar train types and operating speeds.
Yep. I'm sure mechanical engineers and railroad engineers have entirely different sets of criteria.
ns145, you are correct of course, but the thread is only on the efficiency improvements in the internal-combustion prime mover.
Overmod ns145, you are correct of course, but the thread is only on the efficiency improvements in the internal-combustion prime mover.
If we are deciding to compare overall locomotive efficiency against 'first generation' all the points you made are valid.
Intermediate improvements not explicitly mentioned are the introduction of traction alternators on nominally DC locomotives, the introduction of practical 'creep control' and other traction enhancement on DC motors, and the list of practical improvements in the dash-2 series for EMD and thd general improvements and QC in the late -8 and -9 GEs.
Not everything was forward. We might examine 6000hp locomotives in North America, the wretched electronic implementation in the EMD 50-series, and the phenomenon that was the Republic Starships for the 'progress is not always forward' discussion corner.
OvermodIf we are deciding to compare overall locomotive efficiency against 'first generation' all the points you made are valid. Intermediate improvements not explicitly mentioned are the introduction of traction alternators on nominally DC locomotives, the introduction of practical 'creep control' and other traction enhancement on DC motors, and the list of practical improvements in the dash-2 series for EMD and thd general improvements and QC in the late -8 and -9 GEs. Not everything was forward. We might examine 6000hp locomotives in North America, the wretched electronic implementation in the EMD 50-series, and the phenomenon that was the Republic Starships for the 'progress is not always forward' discussion corner.
Progress is rarely if ever a straight line. Not every 'new' idea actually works the way it was intended to work. Such is humanity and its path form the caves and savannas of 100K years ago.
A locomotive is much more than just the operation of its prime mover.
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