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2 Cycle diesels vs 4 cycle

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2 Cycle diesels vs 4 cycle
Posted by daveklepper on Monday, April 30, 2012 3:18 AM

Mention has been made of the 6% fuel savings of four-cycle diesels over two-cylce.

Railroad experience has indicated that maintenance costs can easily make up the difference.

The equivalent horsepower four cycle diesel is large and weighis a lot more than the two cycle or operates at a much higher speed or has come combination of both.   In all three cases, maintenace goes up.

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Posted by CSSHEGEWISCH on Monday, April 30, 2012 6:39 AM

So the fuel-maintenance trade-off is showing up, an issue that goes back to the early days of railroading.

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Posted by YoHo1975 on Monday, April 30, 2012 11:26 AM

Well, and again, That 6% difference was under a specific set of conditions, not universal across all railroad profiles and operating practices. 

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Posted by BigJim on Monday, April 30, 2012 5:52 PM

or operates at a much higher speed

Dave,
They both operate at about the same RPM.

.

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Posted by daveklepper on Tuesday, May 1, 2012 10:06 AM

They both operate at the same RPM if the four-cycle is much larger and heavier.   That is what I meant.

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Posted by edbenton on Tuesday, May 1, 2012 11:01 AM

Lets base this on lets see here Diesel is around 3.50 Rack Price right now without any taxes.  So on 100K gallons a year an EMD will cost 350 thousand in Fuel now a GE will cost you 21000 dollars less PER UNIT Multiply that by 1000 and your getting into some Serious Cash.  BNSF with their GEVO fleet saves about 21 MILLION bucks on fuel over one made up of EMD.  I doubt teh Maintance costs are that much more for the fleet. 

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Posted by creepycrank on Tuesday, May 1, 2012 11:02 AM

No, the GE engine is rated at 1050 rpm for locomotive service while the EMD engine is rated at 900 rpm. GE rates its marine version of the GEVO engine at 900 rpm probably to reduce piston speed to get acceptable service life as marine engines usually run at full speed.

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Posted by YoHo1975 on Tuesday, May 1, 2012 1:20 PM

edbenton

Lets base this on lets see here Diesel is around 3.50 Rack Price right now without any taxes.  So on 100K gallons a year an EMD will cost 350 thousand in Fuel now a GE will cost you 21000 dollars less PER UNIT Multiply that by 1000 and your getting into some Serious Cash.  BNSF with their GEVO fleet saves about 21 MILLION bucks on fuel over one made up of EMD.  I doubt teh Maintance costs are that much more for the fleet. 

 

Assuming that 6% is true across all load and throttle settings. Which it isn't.

And BNSF has plenty of ACes, Dash 9s and MACs as well. How does that figure into fleetwide fuel pricing?

UP has What about an Even split between Gevos and ACes? Why don't they care about that 6%?

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Posted by GP40-2 on Tuesday, May 1, 2012 5:35 PM

YoHo1975

 

 

UP has What about an Even split between Gevos and ACes? Why don't they care about that 6%?

The 6% is the price RRs are willing to pay to keep EMD hanging around so GE has some competition.

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Posted by YoHo1975 on Tuesday, May 1, 2012 5:59 PM

Across over a thousand units? (assuming SD70s also are less fuel efficient?)

 

That's a difference of like 300 gallons per ~5000 gallon tank which at $3.50 rack price (is that the Trucker price? I know railroads get a discount) comes out to roughly $1050 for every tank of gas for every unit. That's serious money. I refuse to believe any company is run that poorly. You don't waste money like that.

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Posted by Firelock76 on Tuesday, May 1, 2012 6:35 PM

Does anyone REALLY know what the railroads pay for diesel fuel?  Seems to be a pretty closely guarded secret!

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Posted by edbenton on Tuesday, May 1, 2012 8:29 PM

The Price I listed was what it would be for Standard USLD without any of the Fuel Taxes on it.  Now RR's Hedge their Costs for Fuel by buying it in Massive Quanities so they get a little discount but Not that much of a break as the Net Profit Margin for Fuel for the Refinery is only 1-2% per gallon.  So maybe they get it for 10 cents less if that.  I know in 2000 my OTR boss at the time bought enough Fuel at the time to run the fleet for 2 years and he had to buy 4 Million Gallons at a cost of over 5 Million Dollars.  The Rack Price then was 1.35 when he bought it so he got a 10 cent discount he had to pay Fuel taxes on what he bought however it was taken out of his prepurchased amount.  So what I am saying would be Close. 

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Posted by M636C on Wednesday, May 2, 2012 5:49 AM

daveklepper

Mention has been made of the 6% fuel savings of four-cycle diesels over two-cylce.

Railroad experience has indicated that maintenance costs can easily make up the difference.

The equivalent horsepower four cycle diesel is large and weighis a lot more than the two cycle or operates at a much higher speed or has come combination of both.   In all three cases, maintenace goes up.

I believe the source of this information is a GE Press Release regarding a comparative test of emissions of a GE ES44 and an SD70ACe carried out a couple of years ago by or on behalf of the EPA.

One loco was from BNSF and one from UP and a stipulation was that the test locomotives were drawn directly from traffic on the two railroads.

Both locomotives met the Tier 2 emissions standards on test, but among the data quoted in the results the fuel used by the locomotives in the trials was quoted.

The GE locomotive did indeed use less fuel than the EMD locomotive in the test and this was seized upon by GE who announced this in a press release. My recollection was that a 7% advantage for GE over EMD was claimed.

So far, all of this was true, but it was also misleading.

The two locomotives were selected more or less at random from locomotives in traffic and in the interests of avoiding the locomotives being "tuned" to meet the emissions tests, no adjustments were allowed to the locomotives.

So has anyone guessed what happened regarding fuel consumption?

The GE locomotive was producing a little more than 4000 HP into the alternator during the tests while the EMD locomotive was putting the intended 4300 HP into the alternator.

When the fuel consumption was calculated as the specific fuel consumption based on the power developed, there was less than one percent difference between the fuel used. I think the EMD did use the fraction of a percent more, but it is easy to believe that the EMD could save that much in maintenance.

M636C

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Posted by edbenton on Wednesday, May 2, 2012 7:44 AM

Your talking about 7 Years ago when Fuel could be found for around 1.50 a gallon OTR Price so say a buck for the RR  not for over 3 Bucks a Gallon like it is NOW.  Here is something to think about for every 10 cents Gas goes up it takes 1.5 Billion out of the GDP in growth per Quarter as it take more Discresanary income out of the MIX.  7 Years ago OTR Rates where around 1.20 a mile and you could still make a Profit on that.  Now if you haul for less than 1.80 a mile YOUR going BROKE. 

This is from when the Fuel testing was DONE a gevo saved 300 gallons on 5000 so you saved about 300 a tankful as you did not need to put in as much fuel.  Now your at well over 1300 a Tankful if not more based on your Hedged cost.  Sorry but no way in Hell is the maintance cost that much Cheaper on an EMD on a 92 day cycle. 

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Posted by YoHo1975 on Wednesday, May 2, 2012 11:20 AM

Ed, who are you arguing with?

At $3.50 a gallon, the difference in fuel cost for 6% difference in efficiency on a 5000 gallon tank is $1050 period, end of story no matter what year you're talking about the math is the same. 5000x.06=300 300x3.5=1050.

 

Anyway, M636C thankyou, that meshes with what I remember. I'm going to try and find the old thread and/or the EPA report to confirm.

And for the record, that explains why NS sets the fuel rails on their GE's to max at 4000HP. 6% fuel savings is a lot of money and they value that savings over the advantages of 400 extra horses.

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Posted by YoHo1975 on Wednesday, May 2, 2012 11:33 AM

This is the railroad net article from 2010 which I referenced in a thread on this topic.

http://www.railroad.net/forums/viewtopic.php?f=8&t=62651

http://cs.trains.com/TRCCS/forums/p/180500/1976816.aspx

Note, GE is being misleading in their press release. The difference is .6% not 6%.

 

So the entire conversation is moot, because the initial assumption "ES44s are 6% more efficient than SD70ACes is wrong. 

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Posted by edbenton on Wednesday, May 2, 2012 11:47 AM

Source for this is the Diesel Shop BNSF has according to the Roster listed 2780 EMDS of all types including the Leased power compared to 3056 GE Locos all of which are 4000 HP or MORE.  So in the High HP Fuel economy model there IS no Comparison When the SD70-75 is outnumber 15 to 1 to the C44-9 it means the Fuel Savings are MORE than the so called maintance Penalty you are screaming about YoHo.  BNSF has More Switchers on the Roster than SD70s that tell you anything. 

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Posted by YoHo1975 on Wednesday, May 2, 2012 11:55 AM

I haven't said anything about the Maintenance penalty. What are you talking about?

 

Furthermore, the information about fuel efficiency is specifically about the GEVO engines and ONLY the GEVO engines. GE themselves claim that the FDL is 3-4% less efficient. So again, what are you talking about? 

And why is BNSF the model here but not Union Pacific? Or for that matter CSX or NS?

Never mind that fact the GE's have been cheaper to purchase for decades now. That was the MO, GE's cost less up front, EMD costs more, but the support chain is cheaper. I don't know if that's true in 2012 with Cat and ACes, but it was true in the 90s and the early 00s.

So again, what are you talking about? Why are you questioning the math of the epa report with arm waving? if you have some proof that BNSF buys GE's for the fuel savings, please present it. 

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Posted by BigJim on Wednesday, May 2, 2012 12:17 PM

creepycrank

No, the GE engine is rated at 1050 rpm for locomotive service


For the most part, the GE engine will run in the upper 900's in 8th notch until the train speed drops below 15mph. Then it will go to the 1050.

.

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