If you are refering to my post, I am talking about the EMD 50 series (SD50) we received in the early 1980’s, not 1950’s era diesel-electrics.
I am not thinking about steam in 1920 era tech either. What I am saying is that if you updated a steam locomotive with every bit of 2006 technology, you would be very lucky to get up to 13%-14% efficiency. Our newest GEVO’s are around 40% efficient.
A four unit F7 lash up from the 1950’s would have about the same drawbar power as the Class J. Hooking the 4 F7s together (25%-30% efficiency each) would still be cheaper that running a 4% to 5% efficient Class J.
Also consider the eastern coal the Class J ran on in the 1950’s is now selling for $70 to $100 dollars per ton. Still want to run a steam locomotive?
The steam vs. diesel tests on N&W were run in 1952. N&W did not modify either 1238 or 1297 for the tests. This story appeared in Nov 1991 Trains, contained errors of fact, and lacked supporting evidence. It was apparent that the author had not done adequate research on locomotive performance capapabilities on both N&W and on other roads, nor did he have adequate understanding of N&W’s physical plant or operations at the time. It rebutted in part by a participant in the tests in the May 1992 issue of Trains. Full rebuttals appeared in N&WHS magazine, The Arrow in the May/June 1994 and Jan/Feb 1998 issues. Both available as back issues AFAIK. It’ a good idea to read all four of these sources before arriving at a conclusion.
I am not thinking about steam in 1920 era tech either. What I am saying is that if you updated a steam locomotive with every bit of 2006 technology, you would be very lucky to get up to 13%-14% efficiency. Our newest GEVO’s are around 40% efficient.
You are 100% correct if you stay with an old flue tube boiler with stoker feed and hand fired but, there are a lot better ways of doing things with todays tech I think you would see efficiency ratings much higher. and not to dispute your word 40% for a diesel is a little high when the best internal combustion engine is somewhere in the high 20% percent range. A loco can only be as good as its prime mover, and them old F units throwed out more pollution than the J’s with their detroits slobbering motor oil all down the sides and out the bottom. Coal 70 bucks a ton or diesel 3 bucks a gallon ain’t much difference, which ever way it costs heap mucho money to run something that big.
Really? I’ve only worked in this industry and with locomotives for the past 27 years. Pehaps you can quote me some source such as an engineering journal that states that a modern turbocharged/intercooled/computer controlled diesel such as GE’s GEVO has an efficiency only “in the high 20% range”
Ley’s not start a bitching match but you show me one that says it is, GE advertises the evo to be 3% more than the current crop of locos, and even this is achieved with a reduction in cylinders ( 12 from 16 ). I have worked in the steam generation of electricity industry, so I also have some background in what I speak, by the way 82% of all the electric power in the US is brought to you by coal fired boilers
My father has read this thread and would like to reply -however I am the one doing the typing. Ok Pop -take it away: “Gentlemen, the debate about Steam versus Diesel is an old one and (at the age of 88) is one that I had to sit and work with. I appreciate the gentlemans response about the Garratts -however tests by myself and others of Messrs Beyer Peacock of Gorton Manchester have shown that the Garratt concept while interesting (and I spent the whole of my time in Bulawayo shop with them) -the main problem remains in the length of the steam pipes and the control system for the individual steam bogies. The gentlemans comment about the infrastructure required to operate steam over that of diesel is a good one. However as has been proved (regretably) a diesal system requires a level of technology not found with a steam locomotive. It requires a pure DERV of reliable Cetane rating -rather than a blend of coal oil and cane alcohol as used by Zimbabwe National Railways. This has lead to the use of restored coal burning class 15s being used to rescue the Canadian sourced diesals. The two Leader experiments by Bulleid showed promise -although Leader 01 was the only one every fired -the turf burner operated more than 4 years in the CIE rail system. As to presumed ecomonical benefits of burning coal over oil in a locomotive -both the GWR and the LMS proved that oil could be ruinously expensive. Our own experiments with coal oil and gas producer fireboxes during the period of sanctions proved that in very few instances does diesal not prove to be more cheaper and economical to run. Currently I am helping my son build his first steam engine, the source books used are (by my standards) old and most of the techniques and technologies revealed in them date from my apprenticeship days. This is probably a dying art -afterall how many courses on flint knapping do you see nowadays?” Your Faithfully Horace W Brades esq" regards ralph
Mea culpa, those tests were with C&O 614 - I still have the video somewhere - in very very cold conditions !!
BTW if steam had continued to develop, I’m sure with computers and electronics you could work out a way to have 2 or more engines “m.u.'ed” like you can with diesels.
Ok, I’ll show you why GE says the GEVO is 3% more efficient that its previous DASH 9 series of locomotives.
Our CW44AC locomotives (the AC traction version of the DASH 9) burn 207 gallons per hour at full throttle to produce 4600 crankshaft HP. Of that, 4400 HP is the nominal traction rating, and subtracting loss from the electrical system, 4100 HP ends up at the rail.
207 gallons per hour = 28.3 million BTU per hour
4600 crankshaft HP = 11.7 million BTU per hour
11.7 / 28.3 = 41.3% The FDL engine is 41.3% efficient in converting the energy in diesel fuel into work.
4100 rail HP = 10.4 million BTU per hour
10.4 / 28.3 = 36.7% Overall, the CW44AC is 36.7% efficient in converting the energy of diesel fuel into pulling power.
Our new GEVOs only burn 196 gallons per hour to produce 4190 rail HP for a total locomotive efficiency of 40%.
40% - 36.7% = 3.3%
GE’s ad was exactly right when it said the GEVO is 3% more efficient than its previous models.
Your orginal statement of internal combustion engines having an efficiency in the “high 20s” is pretty much right for a domestic non-turbocharged gasoline engine. Turbo diesels are a totally different (and much more efficient) animal.
(this is me) Rhodesia Rails used to haul iron and coal trains with 3 class 15(A)s and communication between the cabs was via means of someone walking along the locos and banging on the next loco with a 2lb hammer in a homebrewed “morse”. Later there was radio… I have been privelidged to see and examine both “DELTIC” and “The Duke of Gloucester”. Both of these were built in the 1950’s. “DELTIC” was a twin 24 piston diesal locomotive with a rating of 3,300Hp while “The Duke” was Riddles last design and is still the UKs only working Super Pacific -it is rated at 4,500Hp. The UK operates the worlds fastest Diesal locomotives (the type 43) wether it could still do with a steam based system I do not know. “Mallard” was very nearly completely wrecked by the high speed run and “The Duke” steaming capacity exceeds its feed water system capacity! There are still water troughs in parts of the UK and the problem of getting suitable TIA water into them was never really solved. There are a group of enthusiasts planning on rebuilding a standard 5 locomotive -but the problems that they are facing are enormous… Currently here in the Uk we are having worries about the BoxPok wheels that are the defining feature of one of our most loved class of locomotives -the “Merchant Navy” type as designed by Bulleid. Whe the Big Four became British Rail in the late 1940’s there were a series of trials of locomotives from each of the four companies in order to see which of the designs was the most successful. These were run over 2 years. The results were clear, each of the four companies had designed and built a locomotive that was successful in running on their tracks!!! Thus a GWR “Castles” was the most efficient whilst running on GWR metals. However, the worlds largest user of locomotives, on the worlds largest rail network -had completely switched to diesals in under 30 years. The answer is simple. Diesal may not be as pleasing to the eye as steam. But it is more profitable to use. regards ralph
I’ve been informed that the F-7 tested on was 459 and also that they had their fuel racks
and load regulators slightly adjusted so the total HP was close to
6,800 hp for the diesels.
Maybe both sides cheated in one way or another…lol!
You need to check your inquiry at another site. The steam vs diesel test has been discussed earlier there and references to specific messages should clear up any questions you have. Yes the F7’s were souped-up. The A and Y6 were not. GM had a reason to “win”, N&W didn’t, because it wasn’t selling anything to anybody.
Even if the F7s were “souped-up” two things to note are that: (1) F7s DC electrical systems were only 82% efficient. 6800 Traction HP for them only amounts to 5500 HP at the rail, and (2) You don’t get something for nothing. If EMD did uprate their traction HP, it would show up as an increase in fuel consumption.
Feltonhill, do you have fuel useage data for the F7s used in the test vs “stock” F7 data? If that data is recorded, it would be relatively easy to calculate if, and by how much EMD increased their HP.
If you have access to Jeffries’ N&W Giant of Steam, either the original or the new revised edition, there are comparative fuel usage and cost figures for the A, Y6 and F7’s for the various runs (pg 80-81 in the new book). 6,800 HP for the F7’s is used in the book, vs 6,000 HP stock. From the 459 photo caption, “EMD confessed when questioned by N&W test officials since the dynamometer results exceeded published ratings in service.” There is no direct fuel use comparison betwen the 459 and a set of four stock F7’s.
Also in Louis Newton’s Rails remembered Vol.3, there are first hand observations of some of the 1952 tests, but I didn’t seen any fuel use info for the F7’s. Still, its a good read written by someone who was there and participated in the tests.
The only other possibility may in the actual test report at NWHS archives. I can take another look at it in October when I get to Roanoke. That’s one box on the shelves I have marked!!
I can try to type some figures in here, but it’s a lot of numbers and I’m not sure they would be much use for the type of comparison you want to run.
Thanks for looking. It would be pretty easy to calculate how much EMD rerated the F7s by seeing the actual fuel comsuption data from the tests.
At that time in history, the only way EMD could really increase the rail power of its locomotives was to increase the traction rating by burning more fuel. The technology didn’t exist at the time to increase the efficiency of the electrical side of the locomotive.
While EMD might not have been open with the units HP for the test, I wouldn’t go as far as saying they “cheated” at 1700 traction HP per unit to gain more sales. They released the the 1750 traction HP GP9 the following year.
Add the Withuhn balanced-dynamic-load compounding system and rotary-cam poppet valves and you’d have something similar to a design trainfreek409 and I bounced around in a couple of e-mails several months ago. How practical a 10,000HP 4-8-4+4-8-4 would be is ??? Designing it to MU with today’s diesels would be no big thing.
While a 10,000 HP Garratt sounds pretty impressive and would have lighter rail loadings to go along with it, there probably aren’t too many applications where it could be used efficiently. After all, it can’t be split into smaller units for those days when tonnages are lower. Besides unit trains of mineral freight, I don’t know of too many other assignments that would have consistent tonnage.
While poppet valves are an excellent design and don’t appear to require much specialized maintenance, compounding in any form appears to be an added complication that calls into play the efficiency vs. availability issue. N&W seems to be the only North American railroad that had much success with compounds, and they were low-speed locomotives.
Reasoning behind compounding in the Withuhn system:
Four cylinders per engine (rather like the D&H Leonor F. Loree) to make best use of high (500psi) pressure and maximizes economy. The Withuhn-Garratt would have eight cylinders.
Each engine would have TWO main axles, each driven by two pistons. The rod geometry would be designed to minimize dynamic augment, thereby enabling higher top speed. This involves pistons on the same side of the engine moving in opposite directions and internal coupling of the driving axles to keep everything synchronized.
The entire system was described in a Trains article, with drawings, Did We Scrap Steam Too Soon? which appeared back in 1971 or so.
Incidentally, 10,000HP might be a conservative maximum rating - gross overkill for anything except unit coal service (although the machine should be fast enought to handle high speed intermodal trains.)
As for the low speed of N&W’s Y’s, the villain was dynamic augment, the one thing the Withuhn design was meant to minimize.
I remember when the article was written and I concluded at the time that the proposal was a well thought-out concept. One problem with internal (between the frames) connecting rods is going to be accessibility. The inside-mounted bearings on crank axles would be difficult to lubricate and maintain and would probably be under-maintained since they aren’t immediately visible or easily accessible. The human factor has to be considered, too.
How about coal that is ground into fine powder, turned into a slurry, then sprayed into a turbine of some sort, which turns a generator or a genset then powers an electric motor in the trucks, kind of like a Green Goat, but with a coal fired steam turbine. They can use water injection in jet engines to increase thrust, and can use water injection in a piston engine to control pre-ignition, why cant you use it to expand and run a turbine. Obviously I am not an mechanical engineer of the required sort, but I am an engineer on my Model Railroad. Of course that don’t help me to figure out just how efficient, or inefficient, such a contraption would be, but I think I am barking up the right tree concerning the question.