How far does the average diesel locomotive go between refuels, and how many MPG does it get? Are they all in the same range, or does it vary?
For example, say that a train with a 3000 gal. fuel tank travels 100 miles each day, every day. On day 1, it starts its work with a full tank. How many days later would it need a refuel?
Thanks in advance.
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Tonnage? grade & curvature? MU'd/DPU'd with? Engineer qualification?, wind? axle count?
I think you get the point....
As others said above, everything depends on the route, speed, and weight of train! But I think what you're looking for is averages.
Here's an example that may help. A particular coal train I have worked with runs 1,670 miles round-trip between the mine and the power plant. The route is mountainous throughout, with numerous long ascending grades. The train is 135-cars long with gross weight of 18,500 tons (including locomotives). Each locomotive carries 5,000 gallons of fuel. In that round trip, the train will refill twice, each time each locomotive taking on about 4,000 gallons. So:
Total fuel consumed round trip = 20,000 gallons
Total mileage 1,670
Miles per gallon per locomotive = 0.41.
But again, this is only a specific case. Other cases are much much different.
Another way of obtaining an average is to use the US Energy Information Administration's averages for the U.S. as a whole. EIA found that in 2006, the BTUs per ton/mile average for freight transportation modes were:
So in rough equivalent numbers, if the average 80,000 lb. semi-trailer combination is getting 8 mpg to move 26 tons of freight, the average train is getting 66 mpg to move 26 tons of freight.
RWM
One carrier that I am aware of, for locomotive management purposes, rates the GE AC's for 1100 miles for a full 5000 gallon tank in unit train service. Other, less stressed, services have longer mileage intervals.
Never too old to have a happy childhood!
Of course the idea is that the train is moving a lot more tonnage than another form of transportation with the same fuel, so its more efficient. Then again I would say that anyway since I am a train person. I have seen varying accounts, I do know that railroads sometimes ordered larger fuel tanks to get longer distances out of their engines. I don't know, maybe type of train would make a difference too, but the more knowlegable members here certainly can answer this better.
Hi,
great post Railwayman. This shows very well how efficient the different modes of transportation really are. Surprised that water uses more fuel then rail.
Frank
"If you need a helping hand, you'll find one at the end of your arm."
Here's some dated information on the SD-40 from "Fuel Efficiency Improvement in Rail Freight Transportation," J N Cetenich, FRA-ORD-76-136, Dec, 1975.
Throttle Position Delivered Horsepower Fuel Rate (gal/hr)
8 3100 168
7 2550 146
6 2000 108
5 1450 79
4 950 57
3 500 41
2 200 25
1 58 7.5
Idle -- 5.5
Dynamic Brake -- 25
Depending on speed limits, profile and load, mpg depends not only on the time spent in each throttle position during running, but also in idle between runs. This is why shutting down is such a big issue.
Interestingly, an E8 burned 114 gal/hr at run 8. There is little if any improvement with turbocharging and the 645-series engine with the SD40.
I am not sure how you have reached that conclusion, which is contrary to my experience and knowledge. The table you cited is interesting. An SD40-2 doesn't deliver 3,100 hp. It delivers 3,000 hp into the flywheel of the main generator, and about 2,500 hp onto the rail. That's the only delivered power that matters.
According to EMD, the SD40-2 consumed 164.4 gph at 3,000 hp output into the flywheel, similiar to the table you cited, but the E8 consumed 188 gph at 2,250 hp into its flywheels instead of the 114 you cite.
Here's the numbers from EMD for horsepower per gallon per hour at notch 8 (which is the most fuel-efficient notch in terms of maximum horspower per gallon consumed):
Conclusions:
I am inferring from your post that the 645 engine really didn't accomplish as much as you think it should, relative to the 567. I may be inferring incorrectly, but allow me a comment on that. Horsepower per cubic inch of displacement in an engine family often doesn't increase when total displacement increases, because the engine designers want to live within a certain maximum pressure within the cylinder that's commensurate with the capabilities of the design to resist that pressure. It's possible to increase that pressure but only by making the engine much heavier, and/or accepting a much higher maintenance cost and much lower engine longevity. Weight and dimensional increase outcomes are usually not acceptable in the highly restricted weight/dimensional envelope in a rail application. While it's true that engine technology improves over time, often designers want to use those advances to improve longevity and reduce maintenance cost, rather than hold those even and obtain higher horsepower, because that's what rail customers usually want. There is very signficant improvement in the 645 over the 567, and 710 over 645, in terms of reduced engine maintenance cost and increased longevity. Availability rates that are prime-mover related have more than quadrupled in improvement in my career.
da_kraut Hi,great post Railwayman. This shows very well how efficient the different modes of transportation really are. Surprised that water uses more fuel then rail.Frank
I know very little of naval engineering, but from what I can gather, the problem is the bluntness/width of the hull that is necessary to efficiently accommodate very large tonnages for the amount of steel and overall length of ship necessary to fit in ports, docks, locks, etc. That creates enormous resistance to motion through the water. In order to get high fuel efficiency, the hull shape needs to be more needle-like.
What I would like to know is why does using the dynamic brake cause an increase in fuel usage?
Dennis Blank Jr.
CEO,COO,CFO,CMO,Bossman,Slavedriver,Engineer,Trackforeman,Grunt. Birdsboro & Reading Railroad
Railway Man I know very little of naval engineering, but from what I can gather, the problem is the bluntness/width of the hull that is necessary to efficiently accommodate very large tonnages for the amount of steel and overall length of ship necessary to fit in ports, docks, locks, etc. That creates enormous resistance to motion through the water. In order to get high fuel efficiency, the hull shape needs to be more needle-like.
Perhaps one reason for uisng using (did my keyboard ever foul up on that!) barges is less roadway upkeep expense?
Johnny
rdgk1se3019 What I would like to know is why does using the dynamic brake cause an increase in fuel usage?
They have to rev the engine some to run the generator -- this is needed to produce what they call excitation voltage for the traction motors so they act as generators. Acting as generators they act as brakes.
I suppose you could design self-exciting generators -- the power output of the generator in turn could produce voltage across the field windings to make them work as generators. This is not perpetual motion as you are still converting shaft power to electric power, and you may need some initial excitation or magnetism in the field to get this going.
But I guess it was a lot simpler, safer, cheaper, easier to generate the traction-motor-as-generator excitation voltage with the main generator during dynamic braking and hence dynamic braking uses a little bit of fuel. With expensive fuel one could pursue alternatives to this arrangement, but given the costs and benefits it may not be worth it.
What the AC traction motor locos do is something I don't know.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
rdgk1se3019why does using the dynamic brake cause an increase in fuel usage?
So apparently it takes 25 gal/hr to run a 16-645 at full speed with next to no load.
Don't recall what produces TM excitation current in dynamic-- probably the D14 auxiliary alternator? Not the main generator, in any case.
Railway ManConclusions: Turbocharging increased fuel economy by 12-15%I don't specifically know why E units had such relatively awful fuel economy.
My WAG on conclusion #2 is that the fuel consumption may include the steam generators, otherwise I'd also wonder what was killing the fuel economy of the E's.
I'd wager that conclusion #1 holds more for the 2 cycle engines, and would assume 4 cycle engines would have a smaller increase in fuel economy.
- Erik
I don't think it's the steam generators. More likely it's transmission inefficiency.
I can't think of any 4-stroke locomotive prime movers that did not have turbochargers.
Railway Man I don't think it's the steam generators. More likely it's transmission inefficiency. I can't think of any 4-stroke locomotive prime movers that did not have turbochargers. RWM
A number of the early Alco and Baldwin engines were naturally aspirated. The 660 HP 539 engine in the Alco S-1 had no turbocharger.
The fuel saving from turbochargers on EMD two stroke engines came from the turbocharger uncoupling from its gear drive from the crankshaft at notch 7 (or about). A look at the specific fuel consumption curve for a turbocharged EMD takes a sudden drop around notch 7 at the point that the considerable power being used to drive the blower becomes available at the generator.
M636C
Now why didn't I recall the 539? Since I worked on them now and then? Old age I guess.
The illustration on the turbo decoupling is a good one.
for one thing the E units were 2-567 engines not just the 1 that were in hood units. therefor more fuel used to make the 2250 horsepower
I'm pretty sure the VO series engines from Baldwin were four stroke, and they were normally aspirated.
Does anyone have this info on GE FDL's, or ALCo 251 and 244 prime movers?
That's exactly what I was thinking (about the 2 separate 567's in each E) as I read through this thread. Two other things also crossed my mind. One is that the E's had traction motors geared for the higher "passenger speeds", which probably would have required a bit more effort to make them turn against that higher gear ratio (Ever try to pedal a 10-speed bicycle when it's in too high of a gearing and without downshifting? It takes LOTS of effort on the pedals to accelerate if you don't get it into a lower gearing.) Granted, they would still go through the various transition points at lower speeds, but once they got up to their "highest" setting, they were still working against those higher traction-motor gear ratios. The other point is that, if I recall my physics correctly, wind resistance increases proportional to the SQUARE of the speed, so to go 10% faster, you'll feel about 21% more wind resistance, and to go 40% faster (like about the difference between "freight" speeds and "passenger" speeds), you'll feel almost double the wind resistance (actually about 96% more.) That can't have done much for the fuel economy, either.
Alan
Paul Milenkovicrdgk1se3019 What I would like to know is why does using the dynamic brake cause an increase in fuel usage? They have to rev the engine some to run the generator -- this is needed to produce what they call excitation voltage for the traction motors so they act as generators. Acting as generators they act as brakes. I suppose you could design self-exciting generators -- the power output of the generator in turn could produce voltage across the field windings to make them work as generators. This is not perpetual motion as you are still converting shaft power to electric power, and you may need some initial excitation or magnetism in the field to get this going. But I guess it was a lot simpler, safer, cheaper, easier to generate the traction-motor-as-generator excitation voltage with the main generator during dynamic braking and hence dynamic braking uses a little bit of fuel. With expensive fuel one could pursue alternatives to this arrangement, but given the costs and benefits it may not be worth it. What the AC traction motor locos do is something I don't know.
On the older engines, they rev up to roughly notch 6 in dynamics. Looking back at the rack on the governor, though, shows about notch 2. RPMs without much load.
On newer SD40-2s, they don't rev up in dynamics until about position 6 or so. Not sure of when the change was made, but it was after the test (1975) and before 1978. Some older SD40-2s have been rebuilt/upgraded with this feature.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
Wow. This thread has an interesting collection of truth, half-truth and mis-understood truth. I spent a lot of time doing fuel consumption testing on locomotives - I have the #2 diesel-soaked work boots to prove it - so let me see if I can explain some things.
#2 Diesel fuel: In order to rate the fuel consumption and output of diesel engine in any meaningful way, you need a set of standard conditions. The AAR standards for locomotive diesel engines are:
Air temp - 60 deg F
Fuel temp - 60 deg F
Barometer - 28.86" Hg (typical for 1000' above sea level - which makes Altoona a great place to do tests)
Fuel density - 7.043#/gal
Fuel HHV - 19350 Btu/gal
The engine manufacture typically has empirical correction curves compliled from actual test data that you can use to correct from what ever your test conditions are back to standard.
We always had a lab run a HHV test on the fuel we used for testing. It was always very, very close to the standard - winter, spring, summer or fall - it didn't matter.
EMD blower vs turbo: A biggie! There is no "magic" when the turbo gets off the clutch. It just means there's finally just enough energy in the exhaust stream to allow the turbine to power the compressor. The difference is that the work you would have had to supply from the gear train in on a blower engine, you get almost for free on the turbo. As engine output increases on a turbo engine, the fraction of the power from the turbine increases and the fraction from the gear train decreases. Somewhere between notch 6 and 7 the gear train fraction finally reaches zero.
What does this mean for engine efficiency? A fair comparison would be two otherwise identical locomotives, one with a turbo, one with a blower. See the chart below (I hope it's legible - appologies for using Traction HP instead of Brake HP)
Notice that both locomotives are worse incremental power producers as you move the throttle out. Also notice that both locomotives are close to identical in efficiency up through notch 4. Beyond that, the blower engine starts to "lose its breath" as the blowers have trouble keeping the airbox supplied.
Some other things to note. The power producing capability of the turbo engine is nearly flat once you get past notch 2. There is very little variation notch to notch. The blower engine gets really lousy in the upper notches and notch 8 is horrendous.
Dynamic braking: There were two right answers here. You need to spin the engine to provide excitation for the TM windings AND you need to supply cooling air to the TMs. The excitation comes from the main generator (or traction alternator) - all the companion alternator ever does is run the cooling fans and provide excitation for the main generator. Under most conditions, the engine speed needed for cooling air is greater than that needed for excitation and N4 was a "one size fits all" solution.
However, that mechanically driven TM blower is a HP hog. On a GP38/40-2 it consumes 81 HP at 900 engine RPM and since fan HP goes up with speed squared, reducing the speed saves quite a bit of energy. So, when fuel started to get expensive, EMD came out with two speed DB where they matched the engine speed to DB demand.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
oltmanndThe [dynamic braking] excitation comes from the main generator (or traction alternator)
oltmannd Fuel HHV - 19350 Btu/gal
Thanks,
The difference between Low Heating Value and High Heating Value is the latent heat of condensing the water in the combustion gases. Anthracite and coke would have an HHV only marginally larger than the LHV.
For hydrogen, the LHV is about 50,000 BTU/lb and the HHV is about 60,000 BTU/lb (where lb is a pound mass).
Railway Man Conclusions: Turbocharging increased fuel economy by 12-15% I don't specifically know why E units had such relatively awful fuel economy.
1. Turbo's seem more economical because they only produce usable boost when under a load. When that 645T engine is sitting there idling there is no usable boost from the turbo's and the engine therefore reacts like it's a regular, non turbocharged 8 cylinder. Just like in cars, trucks and such.
2. The 567 series engine was a 2-stroke diesel, I do believe the 645 was a 4-stroke. At any rate 4 strokes are way more fuel effiecent. A major part of the reason why the governent started saying everything from a car to 10cc weed eater should be a 4-stroke design engine.
I may not know alot about trains, but I do know alot about engines. And an engine is an engine. It doesn't matter if its a 6.0L diesel from a GM truck or a 197L diesel from turbocharged V8 train prime mover, it works the same. And just as a side note, back in the early 90's when Dodge/Plymoth came out with the Neon, it was originally planned to have a 2-stroke 4 cylinder engine, instead of the dumb junky 2.0L 4-stroke crapola it had.
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