Lately I have been toying with the idea of what improvements would be most beneficial in when overhauling a locomotive. I'm currently thinking of replacing it's current Type A superheater with a Type E superheater,replacing the lifting injector on the fireman's side with an SA type feedwater heater, with one lifting injector on the engineers' side. I know that I would have to replace both flue sheets and have them punched out to fit the bigger flues and superheater tubes. I also want to increase the boiler pressure 10 percent to 220 PSI. I also am considering adding circulators and drop plugs in the firebox. I'm thinking that this will give me less fuel consumption, better water circulation, increased safety, more horsepower at speed,and more tractive effort. The locomotive is a standard guage 2-8-2, about the size of a light Mike. I cannot at this time give more details of the locomotives' ancestry other than she is also an oil burner. Also I know that the Form 4 is going to have to be dealt with. Am I on the right track here? How much extra to the cost of the rebuild would these improvements add( I know it would be a ball park figure, but you have to start from somewhere.) Any comments would be appreciated.

Likely the #1 best improvement you can make to an American steam locomotive is an improved exhaust system. Lempor exhausts have been fitted to two of the Grand Canyon Railway's locomotives and to one locomotive on the Mt. Washington Cog Railway. Read more about the modifications to GCRY #4960 (a 2-8-2) here:

http://www.martynbane.co.uk/modernsteam ... c/4960.htm

The GCRY locomotives also acquired improved oil burners and feedwater heaters.

I'd think changing the type A superheater to type E superheater would be a huge job and not worth the effort. There are other ways of increasing the superheat temperature, including different type superheater elements (type "HA" elements for instance), making the superheater flues slightly larger to increase the gas flow, or blocking off some of the smaller tubes to force more gas flow through the superheater flues (a technique successfully used by Porta).

Hey, Tex - great to hear about these ideas.

Take a hard look at the valves and pistons, then read the reprinted Porta paper concerned with elimninating blow-by between rings and bored walls. Substantial steam can be saved by actually using it to move the tonnage rather than letting it slip by the sealing components into the atmosphere.

The most improved oil burners require light oil - diesel or similar - not the good old Jiffy Lube waste oil we can burn in our old Van Boden burners. Efficiency comes at the cost of less tolerance for varying fuel quality. Might consider converting to coal with a GPCS, if you are already thinking about heavy boiler alteration.

Chatahoochee Valley 21 was shop retrofit with thermic syphons - after which they couldn't keep her cool. Not sure of they also couldn't keep her tight - but the work can be seen at SERM. Maybe Andrew has some historical anecdotes to include here......

Improving the insulation is easy and obvious. Not so easy or obvious is steam flow and losses through the piping, valves and circuitry. Choke points abound in the supply and exhaust sides. If you check out RED DEVIL there are some very explicit pictures and descriptions of what was done to improve the situation there.

I've always felt that dynamos waste a lot of steam in converting it to electricity. I'm wondering if there might be a better way to illuminate headlights and cab lights these days - maybe radiant heat "solar cell" sort of things which work from invisible heat wavelengths, and could be buried under the lagging to quietly and calmly convert wasted heat into power, store it in batteries, and light up LEDs or other low voltage, very effecient lamps compared to standard tungsten filament lamps. Also eliminates that whine........

Good luck and please keep us informed.

dave

Do not forget rolling resistance. Convert everything you can to roller bearings. That includes your train. Consider converting what you can not put rollers on to oil bath if they are currently running grease, including the rods. Strasburg has been operating successfully with oil bath rod bushings for several years. These improvements will only help at speeds below 20 mph but that is when your locomotive is operating least efficiently. By reducing rolling resistance you can either get thru this speed range faster or pull a little more tonnage. The rollers will also reduce maintaince.

As far as boiler modifications go, I would not convert to type E units. Yes you would make a little hotter steam but the type E is more likely to give you trouble like cinder cutting in a coal burner. This was enough of a problem that some railroads like UP on their last order of 4-8-4's went back to type A deeming the cost of maintaince to high. I know of no railroad that made such conversions but I am sure someone did. The railroads were working their engines hard daily and could not justify the expense and I do not think things have changed that much in the 60 years since. Superheaters only decrease fuel usage during periods of working the locomotive hard so you really need to determine what percentage of time you are going to be working the engine hard enough to justify even having superheaters. You may be better off converting to saturated steam in the long run.

Circulators in the firebox are probably going to do more for increasing steaming capacity than anything else you can do. I would consider some sort of tube type circilator just because it performs the same basic function and is less expensive to install and maintain than a syphon. The 261 has some very interesting circulators in it that I like as do the N&W engines. Simple arch tubes will make a big difference.

Increasing efficiency through increased feedwater temperatures is a double edged sword too. Lifting injectors are more prone to failure than nonlifting injectors but a little more efficient. Feedwater heaters also require maintaince of the pumps as well as the heater itself. I think you will have to run the engine a lot to get any real return on your investment here as well. As hard as Ross has run the 614 and the 261 group has run their engines neither has put a feedwater heater on their engines. The nonlifting injectors do the job and the decrease in efficiency is not worth the headache. If dependability is a very important factor in my decisions on a locomotive rebuild I would go with new nonlifting injectors from the Strasburg shop. I have used one of these and they are good.

Before you make any sort of conversions you need to consider the work you expect the engine to be doing. Will the few thousand pounds of increased tractive effort and few hundred additional horsepower at speed be worth the increased boiler maintaince the additional 20 pounds of steam will cost? Do you have enough weight on drivers to keep the engine from becoming slippery from the additional steam pressure? Is it worth doing the engineering to improve steam passages and the front end much less the actual conversions mentioned by the others who responded? They are cretainly right on both fronts concerning improving efficiency but where is the payback?

This message is not meant to discourage you from going ahead with the project. I know nothing of why your are doing this so I can not possibly answer the questions about a possible return on investment. I advise you to take a look at what the railroads did back in the day. They were very interested in getting the most return for the buck out of their engines and had their own engineering departments as well as those of the manufactures to base their decisions on. Most made basically the same improvements but to different degrees.

Keep us updated on your project. It sounds interesting.

John Bohon

I'm going to play devil's advocate here. I think you can make as much difference by making sure your boiler is tight, setting your valves properly, and training your people to fire and run efficiently. The revised Master Mechanic's front end drafts quite well when you take the time to install it correctly. Tramming the engine well pays dividends also. Making sure everything everything on the locomotive is at 80% is better than having some parts at 100 - 110% and other parts barely working. Something that is often out of our control is to have a locomotive that was designed to do the work you have for it to do. Trying to run a switcher at express train speeds is far from efficient, so is using a Hudson or Pacific to plod along at 15 - 20 mph.

I guess it would be helpful to give you an idea of what kind of territory this engine will be operating under...almost 2 percent grades, longest of which is four miles,some 30-40 MPH running,with a maximum load of about 900 tons. Also, a 100 ton 2-8-0 with a 54 sqare foot grate is a candidate for restoration as well. All the advice is appreciated, and I appreciate the replies I have gotten so far,and I look forward to hearing more of them.

Someone suggested replaceing the dynamo with some other means of generating electricity. If you were to look into it, I think you would be surprised by how little steam a dynamo actually does use.
Roger

One of our members went down to the Chattahoochee Valley shops years ago, when the railroad was still in operation. One of the workers there had fired 21 when she was still in service. He said she was extremely easy to fire, but did not offer any info on the siphons themselves. I think they may have been installed at Southern Iron & Equipment before she was sold to the CHV. She likely received her superheater and power reverse at the same time.

21 had a hydro in the mid 80's around the time that the New Georgia Railroad started up. Mr. Purdie was of the opinion that she would do better on the in-town trips than 750 due to her smaller drivers. I understand that the siphons leaked like spaghetti strainers. However, the engine hadn't been steamed since 1961, so the leaks weren't necessarily due to poor design or installation. For the record, the leaky siphons weren't the reason she wasn't used on the New Georgia. I won't get into the drama that surrounded the early days of the NGRR, as one could likely write an entire book on the subject.

Andrew Durden
Atlanta, GA

Or an article for RyPN - which I hope you will do. A covering of the eventual demise would also be informative.

I've heard some talk about whether or not a front end throttle arrangement providing superheated steam to the appliances lets them operate more erfficiently, or whether superheated steam is actually less efficient in the average injector.

The combination of an axle driven water pump and feedwater heater was very successfully applied on the Cog by Nigel Day. It does rob a bit of HP from the coupler, but maybe less than whats inherent in the quantity of steam used to operate a steam powered feedwater heater pump. Exhaust steam injectors might be best of all - I don't know enough to support any particular option in favor to another. If somebody with an engineering degree and the figures on hand could chime in here......

Again, I do know that using the least steam to gain the most work, entrapment of waste radiant heat through conversion to energy or within insulation, a well designed combustion system, a streamlined steam circuit and exhaust will provide benefits and can be retrofit up to a point.

dave

I have assumed that an exhaust steam injector would add efficiency to a locomotive by using the energy in steam that is otherwise wasted to the atmosphere. Also I think if I understand correctly efficiency is gained with the Lempor exhaust in part by reducing back pressure below the exhaust nozzle. If this is the case then would an exhaust steam injector even work on an engine fitted with a modern exhaust?
Why did late steam in North America not embrace condensing designs like the South African engines, as this would seem to me to add large economies is saving of fuel to heat make up water?

Unless you are running over great distances and at full power, an exhaust steam injector will have pretty disappointing results. From what I have heard from those that have used them, they weren't real happy when they were runnin hard, either. However, you may be surprised that partitioning off part of a tender, running some exhaust steam back to it, and setting up a pump to get the heated water back into your boiler may not put a lot of heat back into your circuit, but you will de aerate the feedwater, which is unbelieveably benificial to the health of the boiler. There was a company (wilson??) that offered such a poor man's feedwater heater system back in the day...I forget what they did for dealing with the residual steam oil.

One improvement I would make is moving the feedwater checks from the side of the boiler to the top. The feedwater will be droping through the steam preheating it a little. Since the cold feedwater will not be comming in as close contact with the course, cracking of the course will be reduced. I think that is the greatest imporvement top mount checks offer in the long run but having seen several shells cracked in this area it is an important one.

John Bohon

If you do your research, you will probably find that any savings of fuel by dealing with warm water are far more than lost in the complexities and energy demands of the combined need for condensing equipment (in effect, giant radiators with forced draught) and draft production in the firebox that replaces the exhaust steam draught. As I recall, the vast majority of SAR Class 25C (condensing) 4-8-4's were eventually converted to 25NC non-condensing. The only real justification for the condensing locos was not energy savings, but water consumption in arid deserts.

See:
http://www.stanleys-steamers.gen.nz/Cla ... alysis.htm
http://www.internationalsteam.co.uk/tra ... dern36.htm (for the math & physics geeks)

+1 on the problems with condensing operation. IIRC, the SAR 25C's saved about 10% on fuel, but cost ~50% more for maintenance. All but one were converted to non-condensing operation before the end of steam in South Africa.