Hi everyone, I have been interested in just how hard it would be to convert a diesel locomotive engine into a successful steam engine? I've read about the White Cliffs Project in Australia and find the information interesting but lacking in terms of converting the typical railway diesel to steam.

There was a proposal to build a modern day steam locomotive reusing diesel engine components in 1982 by the The National Steam Propulsion Company. The NSPC locomotive was to be known as the CE-635 and was to be rated at 3500 horsepower. http://www.trainweb.org/tusp/21_cent.html I would like to know a bit more about the technical aspects of the CE-635 and just how well a diesel block to steam conversion might have fared in reliability and longevity? Seems like a better approach than the ACE-3000 with it's reciprocating drive.

Robert

Hal Fuller's original files for this project are in my archive. You are welcome to PM me. mjanssen@vaporlocomotive.com

William L. Petitjean and Micro Steam applied for patents on converting a two stroke uniflow diesel engine to operate on steam. They designed a single inlet valve cylinder head to bolt on each cylinder of a diesel engine. The drawings indicate that it would be a Detroit Diesel. The text of the application states that the invention can be used on a one cylinder through a twenty cylinder engine. It doesn't say anything about a diesel locomotive. They propose that it would be used with a waste wood fired boiler and a condenser in sawmills etc. The applications were made in 2012 and 2015. Obviously, if one wanted to convert a diesel locomotive, starting with a Detroit diesel gen set would be a cheaper way to experiment. I don't think diesel locomotive fuel is going to get expensive enough anytime soon.

Its messy. Might as well just start over. The wall clearances and rings in an internal combustion engine are all wrong for steam. For it to make any sense, you need super high pressure and superheat, and it needs to have really high cutoff so you expand the steam, and of course it needs to run at high rpm. You are basically replicating a Skinner Unaflow.

There is going to be a lot of condensate in the lubricating oil.

I think the main driver behind this locomotive concept was to allow the railroads to convert to coal fuel while retaining much of the expensive hardware for which they'd paid dearly and with which their operating and maintenance personnel were already familiar.

Wardale mentions these locomotives briefly in his book "the Red Devil..." and didn't have much good to say about them. He was very skeptical of the company's ability to engineer a 1000 PSIG water tube boiler with complete automatic control of water level and firing that would work reliably in railroad service.

I would think that you would have to mount the boiler on a separate car. Since the diesel locomotive is essentially going to be unchanged other than the cylinder heads, there will be no room or no weight capacity left over on the diesel locomotive frame to mount a boiler of sufficient size to power the existing diesel engine.

That is the advantage of the ACE 3000 design in that with direct drive no electrical transmission is needed taking up weight and space.

As previously mentioned, condensation in the crankcase would be a huge problem. It would probably require artificial heating elements in the oil to keep the water boiled off.

Also, fuel economy would probably be 1/3 to 1/4 (if not worse) than that of the diesel that is being modified. You would need a suitably inexpensive source of fuel to power the boiler, not too easy to find.

I remember Ted Miles telling me that steamships, with condensing steam turbines instead of non-condensing steam engines and modern controls were 3-4 time more expensive to operate than a motor ship.

Here, we are talking about a non-condensing steam engine. And you can't count on burning a waste fuel like used motor oil or culm unless your boiler emisions can meet modern clean air standards. Nasty fuels like those tend to increase boiler maintenance costs.

If you look at the drawing at the link to my page posted in the first post http://www.trainweb.org/tusp/21_cent.html, they showed boiler, engine, and generator on a modified diesel-electric chassis. The engine has been cut down to only a V-6, but even with that the boiler would have had to be VERY compact with no provision for manned intervention while the thing was going down the track. I believe an air-cooled condenser and coal supply would have been carried on another modified locomotive chassis presumably with trucks powered from the main generator on the first unit.

The plan may have been just to retain the diesel crankcase and crankshaft; it's possible that the cylinders would have been isolated from the crankcase. That level of detail is not provided in the drawing I have.

The information that's been published on the history of the ACE project confirms what you're saying. They started out thinking about a coal fired steam turbine-electric or reciprocating-electric but eventually decided that the electric drive was an unnecessary step between burning coal and power to the rail. They didn't rule it out completely, the ACE patent includes a drawing of an electric-drive variant, but that wasn't going to be their initial design.

The whole reason for all these proposed locomotives, including the ACE 3000, the Shoemaker locomotive (sort of an updated Jawn Henry with full condensing), and the National Steam Propulsion concept being discussed here, was the use of then-cheap, domestically produced coal fuel. There was no thought of oil firing with any of these designs because there would be no point.

In the early 1980's, coal was cheap while the price of diesel had climbed dramatically. The cost ratio for coal compared to diesel was something like 1:4 per BTU. So a coal-fired locomotive of only 1/4 the efficiency of a diesel of the same horsepower would have the same fuel cost. Diesels at the time were around 30-35% overall thermal efficiency. Traditional steam was around 6-7% and advanced steam hoped to hit 15-20%, maybe higher with very high pressure boilers, compound expansion, and condensing, like the NSP locomotive. So a 15% thermal efficiency steam locomotive would require twice as much heat input as a 30% thermal efficiency diesel to produce the same power, but the total cost of the fuel required to produce that power would be half as much, because coal cost one-quarter as much as diesel per BTU. The large reduction in fuel cost gave you some room to absorb the likely higher first cost of the locomotives and the likely higher maintenance cost of the locomotives in operation and still have a locomotive that was cheaper to operate than a diesel.

A whole lot of development work and a lot of investment would have been required to make these locomotives operational and reliable. By 1985, the cost of diesel fell back to a more reasonable level, which killed most interest the railways had in these projects, and none of them ever got off the drawing board.

James- The locomotive would have been coal fired; that was its only reason for existing, and it would have been condensing. The condenser is not shown on the drawing I have but the exhaust from the engine is labeled "steam exhaust to condensers".

But still, a reciprocating engine running in condensing mode is still not quite as efficient as steam engine because it can only use the expansive energy of steam, while a steam turbine with an LP section can also use the reactive power of steam.

And a reciprocating engine was limited to something around 500 PSI because the steam oil injected into the steam would break down at higher pressures. Steam turbine do not require the use of steam oil (which also means you don't have to separate it from the exhaust steam); I don't know what the greatest PSI marine steam turbine powerplants can operate at; but in theory they could match their land based cousins and go much higher than 500 PSI.

Just to add two more proposals that involved a multi-cylinder engine. In the book "The Steam Locomotive in America" by A.W. Bruce, there is a drawing of a proposed 4,000 to 6,000 hp three unit steam-electric locomotive. The first A unit has the turbine or V16 steam engine and electrical equipment. The B-unit would have either a fire tube or water tube boiler with space for a fireman. The other A-unit would have an operating cab on the end of a regular tender. The locomotive is non-condensing and would have a tractive effort of from 165,000 to 192,000 lbs. The traction motors are under the first A-unit and the B-unit.
The second proposal was from John E.E. Sharp. Besides his proposed condensing Garrett 2-10+10-2 engine, he also designed a diesel style one unit steam electric locomotive with a tender. The steam engine was to be a 6 cylinder DA compound engine. So it wouldn't be a diesel engine conversion. The boiler and condenser was on the unit also. Both his locomotives would have the low pressure cylinders equipped with a turbo-charger that would raise the pressure of the high pressure cylinder exhaust and is powered directly by a turbine using the exhaust from the low pressure cylinders. His presentation as well as Porta's and Withuhn's on the ACE3000 is in a book published in 1983 by the AAR; "Proceedings Railroad Energy Technology: The Alternatives"
Tom Hamilton

As to marine boiler pressures:

The USN's final class of steam propelled destroyer-types were the Knox (DE/FF-1052) class frigates (destroyer escorts when built) which had steam turbine propulsion with 1200 psi boiler pressure. Build dates were 1965-1974.

The USN switched to gas turbine propulsion for destroyer-types with the Spruance (DD-963) and Oliver Hazard Perry (FFG-7) classes.

Phil Mulligan

You may like to look up a similar English project: the Kitson-Still locomotive, which used steam for starting for high torque and switched to diesel operation at higher speed. It had extensive main line trials for about a year before WWII, but one problem, as hinted above, seems to have been that there was not enough space for a big enough boiler for the steam side of the operation.

The Still (later Kitson-Still) and Russian teploparovoz were something different from what's being discussed here. Those used double-acting engines, which were intended to run in steady operation with steam acting against one face and compression-ignition combustion against the other, with at least the premise of recovering the exhaust heat from the combustion in a bottoming steam generator.

The CE-635 and other diesel conversions are full conversions of 2-stroke engine architecture to run entirely on steam, with no retention of internal combustion. This is theoretically 'easily' done for the GM 2-stroke design by modifying the valve arrangement from high-flow exhaust to well-controlled mass admission at the top of the cylinder/power assembly and enhancing the scavenge porting/airbox arrangement at the base of the cylinders for acceptable mass flow at reasonable cyclic rpm.

It is difficult to arrange this for high cyclic rpm, both in terms of the necessary mass flow even if the kind of modified fuel injector arrangement used on ultrasupercritical engines like the ZPE is employed in place of actuated-valve admission and very large plena are provided for prompt exhaust. As noted, although drawings often showed conversion of multicylinder blocks, it seems reasonable that high boiler pressure into a relatively small number of cylinders -- probably 6 -- would be ample for available exhaust packaging or condensation (both of which would tend to limit the achievable horsepower). Even the work done by Combustion Engineering into fluidized-bed coal combustion in the 1980s did not really provide a design capable of sourcing sufficient steam for a workable steam-turbine electric at the time (and I have never seen a mechanical or hydraulic transmission for a converted 2-stroke, although such a thing is nominally possible).

As a potentially interesting aside, there was at one time a considerably well-documented (on the old firedragon site) conversion of a Perkins diesel, in Australia, using bash valves.

While I doubt this would scale directly to a 567/645 size power assembly, I thought it was certainly possible that multiple 'valves' in a single intake could provide the necessary combination of area and time to give workable admission, and there are 'reasonably' practicable ways to implement cutoff on a bash-valved engine of reasonable size and volume. Some form of polyolefin lubrication, probably enhanced with graphite and utilizing condensate extraction, would be workable, and might even be compatible with EMD bearing-shell metallurgy. This gives an engine with no high-speed components in a valvetrain at all, and no defined line contact or unshrouding area between valves and seats, as well as 'uniflow' exhaust (the liners would have to be bored, like single-acting Stumpf cylinders, to suit the average change of temperature from inlet through average effective pressure down to exhaust, but in the context of an engine that is both run and idled at considerable rotational speed to keep the dimensions manageable).