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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 4:07 pm 

Joined: Wed Feb 02, 2011 9:40 pm
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Is it just me, or is this getting a little foamy and frothy?


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 4:24 pm 

Joined: Sun Aug 22, 2004 7:58 am
Posts: 728
Quote:
Is it just me, or is this getting a little foamy and frothy?


A little? Yep, definitely...

I was waiting for somebody to volunteer the cash to pay for all these cool things, but nobody did. How odd!

:-)

Steve Hunter


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 4:50 pm 

Joined: Wed Jan 23, 2008 6:12 am
Posts: 179
Location: North Wales and Australia.
sbhunterca wrote:
Quote:
Is it just me, or is this getting a little foamy and frothy?


A little? Yep, definitely...

I was waiting for somebody to volunteer the cash to pay for all these cool things, but nobody did. How odd!

:-)

Steve Hunter



One thing I have leant is that you never know who reads these forums but never posts. It is these people who if they had the resorces are not going to say publicly for every former and so on will head for them trying to tell them what to spend there money on. It's there choice.


For myself I have worked on steam for nearly forty years and twenty five years specifically such work of the evolution for steam locomotives which are something different but achievable. If I don't say the things which could be done with the right co-operation then they will only be dreams. I pray that one day I will be able to build the loco I describe so it won't be a dream and everyone has the chance to see steam work for further generations.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 5:46 pm 

Joined: Sun Aug 22, 2004 7:58 am
Posts: 728
I definitely hope you get to fulfill those dreams, Nigel. That would delight everyone here.

You're right about those who may be lurking but never post. Hopefully they're content to wade through the foam in pursuit of their interests.

Steve Hunter


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 7:07 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 869
> The heart of what I proposed is based on a
> Chapelon 4-10-2 of around 1950's which was half built.

Nigel, don't you mean 2-10-4?

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Tue Jul 23, 2013 7:11 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 869
Nigel Anthony Hewer Day wrote:
Quote:
sbhunterca wrote:

Is it just me, or is this getting a little foamy and frothy?




> A little? Yep, definitely...


I disagree -- part of any proper modern steam system would be suppression of priming and water carryover... ;-}

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Wed Jul 24, 2013 8:08 am 

Joined: Wed Jan 23, 2008 6:12 am
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Location: North Wales and Australia.
There is two meanings of foam used above. One I don't want to do here and then there's the one directly relating to the boiler water treatment is important and yes a layer of foam acts like a filter on the steam. It has to be treated with antifoam to make it work correctly. High alkaline and tannin braised water treatment would be most important to a super engine. In that respect Porta's system is good. Certainly on the servicing side mentioned water treatment is a high priority and would be used on my loco.

Maybe the most important aspects of an engine are water treatment, good piston rings, good draughting and combustion along with a nice big chime whistle or two.

And yes Robert I meant the 2-10-4.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Wed Jul 31, 2013 10:18 am 

Joined: Mon Jun 24, 2013 1:14 pm
Posts: 98
One of these:

A "doable" Jawn Henry. LOL

-Chris


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File comment: PRR patent filing.
PRR steam switcher US2586109.pdf [634.99 KiB]
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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Wed Jul 31, 2013 3:51 pm 

Joined: Thu May 24, 2012 1:37 pm
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I thought I'd mentioned the Steins locomotive in conjunction with Kirchhof's patent 2518024, which is almost necessary if the little truck-mounted engines are going to be kept synchronized. That is the valve gear that became Franklin type D (as fitted to USATC 2728/611).

There is an oil-fired variant of this design, with longer-wheelbase trucks and very DD2ish styling, running around out there somewhere.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 12:03 pm 

Joined: Mon Aug 23, 2004 12:08 pm
Posts: 254
Location: Western Railroad Museum - Rio Vista
Heresy: I would discard ALL reciprocating steam locomotive technology. I would build a steam electric generating plant on a rail car. Then it could supply power via a cable to any existing electric locomotive. A tank car with large radiators aboard could be used to condense used steam and supply water to the steam generator car. Little additional water would be needed.


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 4:31 pm 

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Note that a regular steam-turbine electric already puts the important parts of that electric locomotive under the steam-generation plant, and uses the seight of the plant for adhesion. Additional connection to road slugs (or, if you want, electric locomotives) is then done if 'more motor' is needed for starting or slow-speed running. There is little reason why you could not also have a pantograph and main transformer available to run under catenary (there are good reasons for a self-powered locomotive to have a pantograph, but I will not go extensively into them here).

You are SUBSTANTIALLY underestimating the amount of radiator surface needed for effective condensing of the level of horsepower needed for a steam-electric plant of the required scale. You might need several tank cars' worth of panels, each with full pressure (and vacuum-capable) connections for the steam and condensed hot water, for just the 8800hp equivalent of two modern diesel-electrics. I have proposed the use of reclaimed 'greywater' to spray on the exterior of the heat exchangers to aid in the condensation process (for which you need separate tank cars, but you would save on the treated and deoxygenated boiler feedwater). You might also use a variant of Holcroft-Anderson 'recompression' to regain some of the latent heat of vaporization for your Rankine cycle -- you would need reasonably constant operation of your expander (steam engine driving the alternator(s)) in order for this to work reliably, but there are ways of achieving that even with the 'usual' sort of real-world train operation...

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 4:38 pm 

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Interestingly Robert, he didn't mention the "T" word. Which begs the question of other types of expanders apart from reciprocating or turbines.......But I think we can't ignore the question of a trade off between the efficiency of the direct mechanical drive in the reciprocating engine and the inefficiency of an electrical transmission and the inefficiency of reciprocating technology and the efficiency of turbines running at steady state. Don't know what trade off consideration is required for other types of expander since he didn't spec any form.

dave

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 6:21 pm 

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I think we can presume he meant the T word because it was a self-contained steam-electric plant, and for that particular service turbines have been preferable (think of them as compound engines with a great many stages). He might have the packaging room for the very large exhaust plena, and very large actual condenser volume and heat-exchanger surface, needed to get the requisite mass flow and low exhaust pressure appropriate for best turbine operation.

One alternative expander is the vane type, which is one of the variable-displacement motors. There are some others, like the Elliptocline or the Quasiturbine, that might have a place in locomotive propulsion but not, perhaps, in steam-electric operation. Remember that a positive-displacement piston motor with good cutoff arrangements can be more efficient at part-load than a turbine. But if you have a large plant, and just one expander, it's awfully nifty to have 'distributed drive' to the wheels, which is one thing that electric transmission does very well. (As is distributed drive to wheels not directly under the locomotive, which is something that steam does NOT do very well...)

The advantage of direct-drive reciprocating power is that there is a peak to the horsepower curve that is in the operating range, and the external combustion means that available power in the engine is not limited to the pressure work done by fuel combustion gas release directly in a cylinder. While there are many -- too many -- steps in between combustion and pressure work in an external-combustion engine compared to an IC engine, there's a combination of heat recovery via the Rankine cycle and the power 'cushion' represented by the overcritical boiler water mass that increases overall system economy... if done carefully and exhaustively (no pun intended).

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 6:33 pm 

Joined: Wed Jan 23, 2008 6:12 am
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Location: North Wales and Australia.
I do not doubt that some of these power stations on wheels are possible but you have understand the power to weight ratio of such machines can be poor. They could be built with whole bank loads of money, no question. Fundamentally you can design any machine but its got to fit the job that's got to be done. Read the lessons of ACE.

Fundamentally an advanced stevensonian loco has still much to offer as a dream that can be realised within an affordable budget. Dreams and I like dreaming of what I could active are only as good as the money behind them.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Thu Aug 01, 2013 7:24 pm 

Joined: Tue Jan 25, 2011 2:07 am
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Ok, this is my electrical engr background speaking. For a reciprocating design, I would be very interested in looking at a 3-cylinder engine, each power stroke 120 degrees apart (similar to the three phases of electric power). Three phases make for a nice smooth power curve. The Shay engine would be a good place to start. I can imagine a modern Shay engine design where each cylinder assembly is removable like a diesel powerpack, and the crankshaft is enclosed in a crankcase. All this is just me daydreaming. I have never studied the works of Chapelon, Porta, Wardale, or the N&W designs, so I am quite ignorant on second generation steam.

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Pistons, Shay locomotive by roy.luck, on Flickr


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