Altnerative steam & modernisation

[Allegheny1600]

The Norfolk and Western Railway was particularly adept at this quick turn around of steam locos, in their case mostly the Y6b and A class Malletts. What finally made them give up on steam and become an all diesel railway

What made the N&W, the C&O, B&O, PRR and many other coal haulers that resisted the onslaught of diesels as long as possible, finally change overnight to diesel power, was the overwhelming efficiency of the diesel locomotive.

Financially,

Horsepower wise,

Manpower wise,

The railways simply couldn't afford NOT to dieselise, the was no way round it and they did try, hard. Just like in Britain, this led to 3 to 5 year old steam locos being scrapped - and these were locos very much at the vanguard of steam efficiency NOT postwar cost cutters, like our 'Standards'!

Cheers,

John E.

[peach james]

John, I would respectfully disagree.  There was more than one reason why dieselization happened as fast as it did, but ultimately, the major one that has been tracked back to, is financial shanagans on the behalf of GM.  Although the railways in the US were very highly capitalized.  That capital was tied up in infastructure, and the offer (particularly from GM, but laterly from GE) of external financing made diesels overly attractive compared with the replacement of old steam.  There was a LOT of very old steam that was past life expired in 1946-9, and the railway companies could not easily access more capital from the stock markets in comparison to what GM was offering (and hence, ALCO/GE/LBH/ect, but to a much lesser extent). 

 

The conclusions I have seen suggest that dieselization was probably a mistake.  The overall cost of dieselization probably cost more than retaining classic steam...but of course, the new and shiny was attractive even if it was not any more efficient.

 

James

[Allegheny1600]

Hi James,

No problem with what you say, at all!

I am only slightly aware of GM's financial dealings but am well aware they definitely got a "leg up" from government during WW2, wern't they the only company allowed to pursue development of large, multi purpose diesels? Wheras Alco only allowed to build small switching units and (I think) such as Baldwin forced to only build steam?

I have a reasonable collection of "Traiins" magazines, could you point me to anywhere in particular for greater details on this, please?

Many thanks,

John.

[peach james]

http://users.fini.net/~bersano/english-anglais/I%20Mech%20E%20Brown%20Paper%201960.pdf

 

Makes interesting reading...

 

James

[jjb1970]

I think the advantages offered by diesel traction over steam were overwhelming. Far superior efficiency, better performance, less labour and maintenance intensive, cleaner and potential for greater performance. The efficiency of any steam system is limited and the emissions (pollution) from combusting coal in locomotive boilers were being questioned long before environmentalism became popular.

To be clear you can clean emissions to air using flue gas de-sulphurisation, de-nitrification, particulate filters etc but the equipment to do it is rather bulky and probably impractical for rail application. Equally, you can do a lot to improve efficiency but I'd be amazed in technologies such as super critical boilers and significant re-heating and feedheating would be practical on a locomotive to give a real efficiency boost. To give an example, by using super critical boilers, all sorts of steam cycle manipulation and heat recovery and operating at extremely high superheat (725C) and by sacrificing flexibility for maximum efficieny the proposed Kingsnorth 5 & 6 coal units were going to offer an efficiency of 45% at design point. That technology is totally impractical for a train but illustrates what is basically the modern state of the art for coal fuelled steam plant. By comparison And there were the issues with labour recruitment and retention. By comparison, an efficiency of 50% in open cycle is easily achievable in a diesel engine offering total flexibility which is available off the shelf.

My issue with diesels is not that they displaced steam but that what should have been a transitional technology between steam and electrification became a long term solution.

In terms of the question, I suspect that if steam had survived longer it'd have been all over black freight machinery.

[peach james]

jib, I would suggest a good read of "The Red Devil" for what the limits of steam are.  As long as the fuel is less than 1/5th the price of diesel oil, the practical n of conventional, FGS, is more than high enough to equal from a cost prospective, diesels.  The remainder of the costs are largely a wash, as the paper referenced above indicates.  There are some advantages of FGD, the big one was the ability to shut down and restart.  In North America, this was basically ignored- by the use of water only as coolant, the F units and similar HAD to be left running for 4-5 months of the year.  Where FGD was used sensibly, for example on shunting applications that were very intermittent, then it was much better than steam.  When the usage started to get to >50%, there was little to choose. 

 

Again, without rehashing The Red Devil, it goes through a lot of the information covered in the paper above, and what good engineering judgement would state, that steam is much closer to early diesel than you might think.  Had the majority of steam not been more than 20 years old, then it might have made a better showing.

 

James

[jjb1970]

Thanks for linking that report! I read it and to be honest I stand by my earlier opinion. The report is limited to analysing cost and does not dwell on the wider issues of energy efficiency (beyond noting the wide difference in thermal efficiency between diesel and steam), man hours, emissions and labour issues. The performance consideration in the report is very misleading I think.

Looking at the reports principal argument which is to demonstrate that diesels did not offer a cost advantage I think that the report is based on a lot of assumptions and approximations and it is not clear that the report has carried out a meaningful comparison. Some sections raised an eye brow, the lack of interest or dismissal of utilisation is very odd given that productive time for an asset is a key performance indicator. The report notes the superior availability of diesels but writes this off as being of no great consequence. The performance section gives an impression that steam offered comparable performance with a diesel except at starting and infers that diesels suffered from slip without considering wheel slip for steam engines.

I also think the reports intro explaining that a ratio is the appropriate means of compensating for inflation is highly simplistic and assumes that the relationships between numerators and denominators is representative of diesel vs. steam costs ignoring other considerations yet at the end the author seems to contradict this premise in stating that financial performance is derived from a wide range of factors. That the report does normalise some figures for inflation effects is interesting. The time basis used for diesel depreciation is also very short although we do have the benefit of hindsight.

I think more meaningful comparators would be to look at things like man hours required per x hours of service, availability/utilisation, thermal efficiency, fuel consumption across the operating range and train performance and operational flexibility. I think ultimately the fact that no country has seriously tried to promote steam as an alternative to diesel or electric traction other than countries where certain political factors not really related to railways were at play since around the time this report was written speaks volumes. Yes, there have been some efforts to build advanced steam locomotive, probably the most famous being the actual "Red Devil" in South Africa and the US ACE proposal but these were either still born proposals or historical anomalies at the margins. And even looking at the Red Devil, in efficiency terms it was still very poor. Diesel engine efficiency has improved enormously since the 50's and 60's along with service periodicity, lubricant consumption, power/weight ratio, emissions performance etc yet efforts to propose advanced steamers are playing with wringing a bit more out of a technology which had been developed almost to the limit of its potential many years ago.

Just my thoughts.

[peach james]

As someone who holds a operators certificate for a 33% efficient steam plant, I beg to differ on a lot of grounds.  While diesel may get higher n than steam, the fuel required to do so is of quite a bit higher quality than that required for steam.  (we pulled a matt 1-2' thick of sludge out of our settling tanks, which we had successfully been burning...try that with a diesel...).  In the context of SA steam, the alternative (SynOil diesel) was quite a bit less efficient than steam, because of the extra steps involved.   The overall limits of conventional steam are about 6-8%n on an ongoing basis- the Red Devil tables show higher than 12%n overall.  If SynOil is used, and a 50% recovery rate it achieved, the diesel equivalent would be about 15%n, which would suggest that the differences between first generation steam and first/2nd gen diesel for n is much closer than many were lead to believe.  (again, arguments raised in the report mentioned above). 

 

Overall, the traction policies of all nations were greatly affected by external factors- it is quite clear from "The Red Devil", that electrification is the preferred solution for highly used lines.  It is when traffic volume does not justify electrification that things get interesting, and it would be my position that in the middle between a train a week and a train every hour, there is a place for first gen. steam, even now.  It is not a question of it answering all demands- clearly, a kof or 08 is far more efficient if you need the engine once a day for 10 min, but if the engine is going to do 8 hours work, then steam may well be equally capitally efficient as diesel is.  The advantages given to diesel in order to "win" in the UK were fairly substantial- things like new TMD's for diesels, whereas steam was struggling on with sites which had been built 100 years before, and a management system that promoted higher utilization of locos, to get the most from them in the work day.  Had some of the efforts which were required to make diesels work commercially been applied to steam, I am quite certain that steam would have lasted substantially longer on the mainline than it did. 

 

James

[jjb1970]

As someone who holds a operators certificate for a 33% efficient steam plant, I beg to differ on a lot of grounds.  While diesel may get higher n than steam, the fuel required to do so is of quite a bit higher quality than that required for steam.  (we pulled a matt 1-2' thick of sludge out of our settling tanks, which we had successfully been burning...try that with a diesel...).  In the context of SA steam, the alternative (SynOil diesel) was quite a bit less efficient than steam, because of the extra steps involved.   The overall limits of conventional steam are about 6-8%n on an ongoing basis- the Red Devil tables show higher than 12%n overall.  If SynOil is used, and a 50% recovery rate it achieved, the diesel equivalent would be about 15%n, which would suggest that the differences between first generation steam and first/2nd gen diesel for n is much closer than many were lead to believe.  (again, arguments raised in the report mentioned above). 

 

Overall, the traction policies of all nations were greatly affected by external factors- it is quite clear from "The Red Devil", that electrification is the preferred solution for highly used lines.  It is when traffic volume does not justify electrification that things get interesting, and it would be my position that in the middle between a train a week and a train every hour, there is a place for first gen. steam, even now.  It is not a question of it answering all demands- clearly, a kof or 08 is far more efficient if you need the engine once a day for 10 min, but if the engine is going to do 8 hours work, then steam may well be equally capitally efficient as diesel is.  The advantages given to diesel in order to "win" in the UK were fairly substantial- things like new TMD's for diesels, whereas steam was struggling on with sites which had been built 100 years before, and a management system that promoted higher utilization of locos, to get the most from them in the work day.  Had some of the efforts which were required to make diesels work commercially been applied to steam, I am quite certain that steam would have lasted substantially longer on the mainline than it did. 

 

James

The quality of fuel required by a diesel engine (noting that few diesel engines are actually diesels in the true sense) is basically a question of fuel treatment. A diesel can operate well on almost anything, they regularly operated on 600cST 4.5%S RFO when such fuel was available and virtually all medium speed engines can be set up for 380cST 3.5%S RFO providing you can heat and filter the fuel. And heating and filtering is not a problem in a power plant application although it wouldn't be practical in a rail application. Is your power plant using reciprocating technology and fire tube boilers? A turbine is a completely different technology than a reciprocating technology as is a water tube boiler, in a sense it is like comparing a gas turbine with a diesel engine. As noted in an earlier post I made in this thread, modern coal fired power plant can get over 40% efficiency however that is based on using technologies such as super critical boilers and pushing pressures and superheat right up to the limits of what metallurgy can currently accommodate as well as multi-stage steam and feed re-heating. Some feed and steam re-heat is doable on a steam locomotive but nothing like that which can be achieved in a power plant.

Where does the comparison with coal to liquid fuels come in? South Africa used synthesised coal to liquid fuels to get around apartheid sanctions but at that was a very particular case. The comparison made in the paper was not a 1st generation diesel to 1st generation steam one, it was a 1st generation diesel to de-facto final generation steam. The figures used in the paper are all based on assumption, and not just a single assumption but assumptions derived from assumptions which is equivalent to being meaningless.

In considering the efficiencies of any thermal system is is a bit like aircraft performance. Looking at the optimum design point can look good but be very misleading. One of the great attributes of a diesel engine is that they have quite a flat efficiency profile across a wide part of its load range and they maintain good efficiency at high turn down ratios.

The figures quoted in that paper even reference availability. Availability is the percentage of time an asset is available for service. If diesel availability is 90% it does not mean it operates 90% of its life, it means that it is available for 90% of its life, ie. it is not broken down, being serviced, undergoing repairs or otherwise not available. The huge difference between availabilities found for steam and diesel even this paper notes have huge implications for economics. However utilisation is important. That is about management but here the flexibility of a diesel (or electric) makes a huge difference due to the start/stop flexibility of a diesel.

I'm sorry, but the paper does not really present a credible argument.

[Suzie]

I read the paper too, and I suspect they would have come to the same conclusion in the UK a couple of years later after assessing the performance of the pioneer modernisation plan diesels with most of them having a ten year lifespan, low performance, and low availability.

 

They concluded that use of Diesel was ideal for road switcher locos, which is what British Railways went and ordered without realising that they did not really need any type 1s! Not surprising that poor decisions were made when the data available was not of the standard we are used to today.

[jjb1970]

I think in the case of the modernisation scheme the sorry state of much of the equipment bought and the short working life was much more a reflection of rushed and ill considered procurement rather than of technology. Some of the modernisation scheme diesels were very good, the Class 20 was a very solid and long lived locomotive in particular. And the diesel multiple units were generally very good, OK enthusiasts tended to hate DMUs but they gave good service and were instrumental in keeping many secondary passenger services viable I think.

[Allegheny1600]

Totally agree with that!

If you compare what the US market was producing by the time we got around to building diesels, well! "even" Alco, Baldwin and Fairbanks Morse could generally build better than than anything except English Electric!

As for GM and presently (1959) GE, they tended to surge ahead in the reliability stakes, I can't put my hands on it right now but I'm sure I've seen reliability figures for GP9's of around 200, 000 per casualty, some ten times that of a class 25!

Now, if we had bought GM fitted locos instead of Sulzer?

What kind of miles per casaulty figures did steam locos give?

Cheers,

John.

 

PS I do love steam locomotion, I'm just aware of it's shortcomings as a form of traction. Remove the coal/fuel burning, generating steam part and you've got the perfect form of traction (via electric cables!).

[peach james]

1.  The plant I am certified for is a turbine/reduction gearing ship plant, of 21 000 SHP + 2MW (e), with oil fired water tube boilers.  Boiler n at rated was 88.7%, plant at 21 000 SHP was rated at 32% n, and by my math, actual operational conditions (which tended towards 14-16 000 SHP or less) was around 28% n from fuel in > SHP + (e) out. About 500 kw were required for ancillary loads, we averaged something like 1.1-1.2 MW (e) load, and at 16 kts ordered, averaged about 7000 lb/hr of fuel consumption.  Max speed was 105-107 rpm, giving an ordered speed of 21-21.5 kts, and usually we were at fuel flow limits (2x7050 lb/hr, of F76.  That gave an indicated SHP of around 20 000, along with the demand from the evaporator(s) of about 10 000 lb/hr of steam.  (Shower water cost about 2.5 p/L to make...)

 

2.  I am well aware of the problems of basing calculations on a bed of sand.  The best I can offer is that the basic figures used in the paper presented above have not been challenged at a professional level.  Again, using The Red Devil as being valid research material, it would appear that from fig 8 in my copy, that the cost of maintaining the 25NC's in South Africa was less than 1/3rd the cost of maintaining the equal HP of diesels (cost per 1000kW-km- 25NC 8.65 cents, Class 31 diesel- 24.20, Class 4E electric 11.80).  From Table 10, the estimated service live of a 25NC was 147 170, vs a 31 at 118 260 (or about 33% more hours of operation for a "modern" steam engine vs a diesel of equivalent timeframe).  From Table 12, the n given for a class 25NC was 3.2%, and the Class 31 Diesel at 23.1 n.  ""Despite the very low year round thermal efficiency figures estimated for it, steam traction showed lower fuel costs than diesel traction in almost all given cases and close to the coalfields it was in some cases competitive with electric traction"".  From Table 13, 25NC at $0.1700 per 1000 MJ at 600 km from coalfield, vs a Class 31 Diesel at $0.1863.  At the coalfield, the 25NC price drops to $0.0583.  From Table 14, cost of operating per 1000 MJ, class GMA/M total operating cost was 26.31 vs 25.42 or 22.27 (single or MU'd) for the Class 31 diesel.  (data for 1975). 

 

So, from where I stand, the numbers as outlined in broad strokes in the paperwork appear to be of the right order of magnitude.  The capital costs to BR of throwing away engines with an economic lifespan of 30+ years (all the standards, basically) at less than 9 years for most engines, was staggering.  The cost of keeping the standards running would have been far less than the policy which was followed of replacing them 1x1 by diesels.  There were areas where dieselization as fast as possible make sense- DMU's on branch lines replacing both life expired engines and coaches at the same time made sense.  The relative cleanliness of a DMU vs a Sentinel style steam MU even, meant that there are substantial advantages to such a change over.  The fact that there was enormous traffic pattern changes ongoing which were driven by external to BR factors is very much relevant.  (same thing goes here, but a lot of the changes had already happened between 1920-1940, when the Ford T dropped to $395).  But, from where I stand, there was a lot of keeping up with the Jone'ses at work.  (as in, we don't want to be seen as backward, even when math shows that we should be...).

 

These are now all historical really- as no-one is about to go back to coal fired steam now.  (well, sort of...coal fired steam electric has the lowest overall costs in high utilization areas)  but the conventional coal fired steam loco is, I think, dead.  I am strongly suspicious that the change over which happened had a bit of economics driver (USA), and a lot of keeping up with the USA (UK), and everyone else is doing it so we should too (SA, China).  As has been noted above, railroads such as the N&W in the USA which were staunch steam supporters, changed relatively quickly when the infrastructure for support went away.  Building an engine is easy, if 1/3rd or more of the parts can be bought in.  Building an engine when EVERYTHING must be made by the railroad shop is much harder.  It's a question of scale- as long as companies such as Worthington were making air compressors, Cofflin making feed pumps, ect, then buying in was _far_ cheaper than making in house.  As the number of railroads using steam dropped, the suppliers went down. 

 

You should have seen the look on the Weir pump guy when we asked for parts for the fuel transfer turbine driven pumps on the tanker in 2011...they were...um...challenged...by the fact we were using 1965-7 made turbine pumps.  (& Cofflin CG feed pumps...same as Jawn Henry used). 

 

James Powell, Cert 3A (Protecteur)

 

* the $ numbers used were in Rand, but it doesn't matter what they were in, as we are looking for comparative prices)

[darren01]

Hi

I have somewhere a works plan of a re built west country and at the bottom of the work it say withdrawer  date 1984!

Now that would have been interesting to still see them running in 84.

Darren01

[jjb1970]

I don't think anybody would argue against the argument that the BR modernisation plan was poorly handled. The combination of a head long rush into dieselisation was always going to be problematic if not well managed. That however as I say is not really a reflection on the relative merits of steam vs. diesel, rather a reflection on poor procurement.

In terms of what the paper looked at, even if we were to accept the argument of the figures (which I don't, they're not valid comparators) the paper does not look at the appropriate metrics to evaluate the relative costs of a diesel vs. a steam locomotive and the figures offered for useful life are not reflective of reality I think.

If looking at man hours per hour in service, thermal efficiency (both at design point and across the operating range), locomotive availability and performance there is just no credible evidence in my opinion to suggest anything other than that a diesel is markedly superior, and by a wide margin.

Even if you look at marine plant, which is a completely different technology to a steam locomotive there are just no real arguments for raising steam is a combustion boiler. Efficiency is very poor next to equivalent diesel plant and steam turbine plant pretty much died a death after the oil crises which followed the Yom Kippur war. The one sector that retained steam turbine plant was LNG carriers and that was only because for a long time it was a lot easier to burn boil off gas in a boiler than in a diesel engine. Since suppliers offered BOG arrangements suitable for diesels steam has died a death even in the LNG sector and some of the more modern turbine LNG carriers are looking at conversion to diesel as the relative efficiencies and operational costs of steam turbine vs. diesel are so far apart. Given that a diesel is much more efficient, is just as fuel tolerant if considering liquid and gaseous fuels and more flexible there is really no argument in favour of steam. Over the years a few companies have tried to develop higher efficient steam plant for marine power and propulsion and in every case they've been unable to get around the fundamental problem that they cannot make the efficiency anywhere near close enough to an equivalent diesel plant to make it viable.

Where steam does become potentially attractive is as part of a combined cycle gas turbine plant using waste heat recovery steam generators. That has been normal in land based power generation for many years and is being proposed again for marine use. Given that modern gas turbines are somewhere above 40% efficient at their design point (still way below a diesel) if you put them in a combined cycle the package efficiency becomes very good. However, the potential attractiveness of a marine CCGT package is very sensitive to vessel operating profile.

The assumption that it is not sensible in terms of cost to replace relatively new assets is also not correct. That depends on a whole range of factors but again if we look at shipping as an example many steam turbine ships were converted to diesel almost as soon as leaving builders yards in the 70's as the difference in fuel costs were so great, some were just laid up and never used as they were not worth operating. We now see very young steam LNG carriers being prepared for conversion to diesel at very high cost, again the difference in operating costs means the return on investment is actually very attractive.

Steam plant using combustion boilers does have two big attractions, it is very easy to burn solid fuels of very poor quality (where permitted and with suitable emissions abatement) and you can go up to very, very high powers. The solid fuel suitability is unlikely to be of much use to trains as emissions regulations would prohibit use of such fuels without emissions abatement which would be extremely difficult to attempt on a train and solid fuels storage and handling issues mean ships are not interested. And as for powers, power plants are looking at 100's of MW or into GW, the sort of power outputs of trains and ships are well within the range of diesels. If you are looking at liquid or gaseous fuelled installations of low - medium power output then it is hard to make an argument for steam other than as part of a CCGT installation.

And all of the train arguments ignore two really rather fundamental arguments, at least in terms of the UK and Western Europe, availability of labour and clean air legislation, both of which were lethal to steam locomotives. I suspect that with or without the BR modernisation scheme steams life in the UK would have been brought to a close by moves to outlaw the technology under clean air improvements if BR had not already been committed to phasing out steam.

[Ozexpatriate]

I apologize if I am saying something redundant but I haven't read in detail all of the comments since this thread was revived in the last week or so.

The 'big coal conveyor belts' of the US mid-Atlantic really tried to keep coal as fuel. I remain fascinated with their steam+electric traction experiments (like the N&W Jawn Henry, and the C&O M1 Class). These were amazing beasts but at the end of the day they weren't reliable enough for day-to-day operation.

 

The first generation diesels weren't faster and they weren't stronger than steam locomotives and they probably weren't more fuel efficient (at least while actually hauling trains).

The fundamental reasons for the end of steam are two-fold and they have nothing to do with machine efficiency while operating.

1. The staffing requirements for diesel drop dramatically
2. They are immediately available when switched on - which relates back to point 1.

[jjb1970]

I'd find it hard to believe that fuel consumption of a diesel was no better than a steamer given that even before WW2 diesel engines were much more efficient than steam plant. Even as early as the first decade of the 20th century it was apparent that the infant diesel engine was significantly more efficient than contemporary steam plant, even at that point fuel consumption for marine plants (which are much more efficient than a steam railway locomotive) could be 2 - 3x higher than an equivalent diesel plant. The problem in those early days was getting diesels big enough to offer useful power and reliable enough to work, both of those aspects were well sorted by the end of WW1 and by WW2 the diesel was a mature technology.

[Ozexpatriate]

I am only slightly aware of GM's financial dealings but am well aware they definitely got a "leg up" from government during WW2, wern't they the only company allowed to pursue development of large, multi purpose diesels? Wheras Alco only allowed to build small switching units and (I think) such as Baldwin forced to only build steam?

The Electromotive Division of GM was permitted (and contracted) to build diesels for boats during WW2 and also war-effort related locomotives. There was very little locomotive development during the war years. Once the war was over, EMD was ready to roll out locomotives using expanded production capacity developed during the war.

 

Total production of the EMD E6 (1939-1942) was 91 A units + 26 B units.   Production of the E7 (1945-1949) was 428 A units + 82 B units.

[brack]

I'd say br steam should've lasted about another 10 years, survivors concentrated in industrial locations, most likely pulling coal (and probably still J27s there at the end), with the money saved put towards electrification. We'd be in a much better position had that happened, there was little justification for scrapping brand new equipment, and the early diesels were ordered in large numbers without being properly tested in service. The fears about finding employees seem surprising - collieries had miners, and often found folk to look after and drive their steam locos for a few years past 1968. I agree that more than an extra decade seems implausible, so would accept a similar timescale to the west Germans as a sort of natural end of steam.

Where steam should have lasted, and would likely still be viable, are undeveloped countries. If you look at the Benguela railway, their modern locos (lovely big garratts and 19d derivatives) were fuelled on eucalyptus wood grown line side on railway owned plantations (carbon neutral - way ahead of the game!) Their workshops could replace or repair any part needed, and labour costs are small (look at how Eritrea were able to rebuild and reactivate their steam locos fairly easily with minimal money, just using machinery and skills that'd been there since the 1930s) Choosing to swap that for diesels dependent on expensive imported fuel, difficult to obtain spares from abroad and requiring advanced machinery and a more technically adept labour force to maintain was foolish, yet repeated time and again across Africa and Asia. Diesels for shunting or intermittent work is a no brainer, but if a loco is going to run 300 miles relatively slowly the time taken to light it up doesn't become as much of an inconvenience.

[peach james]

I'd find it hard to believe that fuel consumption of a diesel was no better than a steamer given that even before WW2 diesel engines were much more efficient than steam plant. Even as early as the first decade of the 20th century it was apparent that the infant diesel engine was significantly more efficient than contemporary steam plant, even at that point fuel consumption for marine plants (which are much more efficient than a steam railway locomotive) could be 2 - 3x higher than an equivalent diesel plant. The problem in those early days was getting diesels big enough to offer useful power and reliable enough to work, both of those aspects were well sorted by the end of WW1 and by WW2 the diesel was a mature technology.

 

 

It's not that.  Diesel (or MGO/F76 ect) is a refined product.  Coal is not.  Diesel is imported into the UK, and RSA.  (or was in the timeframes mentioned- pre North Sea Oil).  So, there are some substantial differences in overall costings of diesel in relation to coal, which were not so much at play in Canada/USA.    Some of the test runs of 614T in the USA as outlined in "The Red Dragon", and in other fairly recent documentation show that the fuel costs were cheaper for 614T on some of the runs than the equal diesel, even given the issues they were faced with.  

 

(614T was run by Russ Rolland (sp), on Chessie System rails in 1981-2 timeframe, hauling coal trains.  This is 614, a modern 4-8-4, that they ran in conjuction to the ACE program for a modern 4-8-4.  There were substantial problems with the whole "test" program, as it was basically run as a publicity stunt, with an engine that was to be blunt, not ready for mainline service during that timeframe)

 

The data provided above also clearly indicates that- ""Despite the very low year round thermal efficiency figures estimated for it, steam traction showed lower fuel costs than diesel traction in almost all given cases and close to the coalfields it was in some cases competitive with electric traction".  From Table 13, 25NC at $0.1700 per 1000 MJ at 600 km from coalfield, vs a Class 31 Diesel at $0.1863.  At the coalfield, the 25NC price drops to $0.0583."  

 

Figures don't lie, but Liers do Figure !, so some expression of doubt is certainly possible with those figures.  It's just that when your fuel costs well less than 1/3rd as much, then you can afford to burn 3x as much and you will still be ahead.  The overall n given depends on how much time the steam engine is used, as a huge amount of energy (and effort) went into keeping engines hot and then not using them.

 

(again to give a FOM to the n involved, the tables in "The Red Devil" give steam about 3.2% n, and Diesel about 21 %.  And steam was still cheaper for fuel...

 

James

[jjb1970]

I certainly agree that fuel cost is important and can offset efficiency in monetary terms. There are two separate and distinct factors, relative cost of fuel and absolute cost. Marine is a good example of these two factors, since the oil price crash the differentials between the various grades of marine fuels have stayed reasonably steady (eg. price of RFO vs. MDO) however the absolute price of fuel has plummeted. The effect has been that interest in alternatives such as LNG and methanol and some of the hybrid low sulphur oils has dropped off hugely as although some of them are still cheaper than oil in the current environment the savings are nothing like as attractive as they looked three or four years ago.

Something to remember about coal is that it is a bit like oil in that coal covers a wide range of fuels, from crappy brown soft lignite through to hard anthracite steam coal. Boilers are very sensitive to the quality of coal in terms of performance and efficiency and also maintenance. Although coal is an abundant resource, the percentage of high quality anthracite type coals is much less so and even before the end of British steam high quality steam coal was becoming much harder to source domestically.