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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 6:56 am 

Joined: Thu May 24, 2012 1:37 pm
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The objections to a modern Shay would not center on the engine reliability, they would center on things like the off-center balance of the chassis and the downright lousy characteristics of drive to the wheels.

One thing to remember is that the power transmission of a double-acting engine is different from that of a single-acting engine like a conventional diesel; in electrical terms it is six-phase. So even torque peaking becomes less of a concern. For packaging reasons, however, it may be better to consider the V4 "Heisler" sort of arrangement, as a DA V-4 (90 degree bank angle) has exceptional balance, fits neatly under a conventional boiler, could be made with a shorter crank with just two throws, and is amenable to your sectional engine construction (in fact, even more so because there is less structure impeding removal of the 'powerpacks', and involving no more care in R&R than is already required for a V-configuration diesel engine). You also get nice Cardan-shaft drive close to the centerline, and enclosed gearing to drive the wheels is then centered, can be frame-mounted in the trucks and quill drive used to reduce the unsprung mass, etc. etc. etc.

Remember that a locomotive is a full system, not just a motor with some appurtenances attached. If you are dedicated to the three-cylinder approach, mount it transversely, either as Bulleid did in Leader, or as a vertical engine a la Sentinel (either of which you can look up online to get more details than I could use for MEGO induction on this list). The vertical approach would be easier to modularize.

I'd also mention that you must use care when building steam motors with enclosed crankcases -- if these are also used as lubricant sumps, any blowby or leakage of steam will contaminate the lubricant. You can either design explicitly for tolerating water in the lube, or design the 'powerpacks' to have a full crosshead external to the sealed part of the crankcase (as was done in some automotive steam applications).

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 9:54 am 

Joined: Sun Aug 22, 2004 7:19 am
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Location: southeastern USA
OK, so we build a Shay with triple expansion engines on both sides of the boiler, set as much in opposition to each other as possible strokewise for minimal impulsiveness (60 rather than 120) and run a keel condenser in the wet ditch alongside the ROW.

A question I was thiniing about regarding waste heat in locomotive style boilers...... is the remaining heat in the products of combusion that come out of the tubes into the front end used for any purpose in the operation of the front end or is it just shoved out the stack having done nothing of use after leaving the tubes?

dave

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 11:47 am 

Joined: Sun Aug 22, 2004 8:31 am
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Location: South Carolina
Dave wrote:
OK, so we build a Shay with triple expansion engines on both sides of the boiler, set as much in opposition to each other as possible strokewise for minimal impulsiveness (60 rather than 120) and run a keel condenser in the wet ditch alongside the ROW.

A question I was thiniing about regarding waste heat in locomotive style boilers...... is the remaining heat in the products of combusion that come out of the tubes into the front end used for any purpose in the operation of the front end or is it just shoved out the stack having done nothing of use after leaving the tubes?

dave


Dave,

Love that condenser idea! We could even use track pans so we didn't have to worry about weeds, snakes, and snipes getting hung up in our condenser. ;-)

Any temperature difference between the gases leaving the stack and the surrounding air represents "lost" energy. The more heat you extract from those gases before they leave the boiler, the more efficient your boiler. The downside of this is that when the gases cool to a certain point (something less than 180 degrees F or so) the water (which is a product of burning fuels containing hydrogen) begins to condense out. This is good from a thermodynamic standpoint (condensing water transfers a lot of heat), but bad from a durability/maintenance one. This water combines with sulfur in the exhaust and forms sulfuric acid which tries to eat your boiler and smokebox parts. I understand this was a real problem with Franco-Crosti boilers with their supplemental preheaters. Some of them used porcelain-coated tubes to try to deal with this.

Many modern boilers used to provide heat for buildings are of "condensing" type, in which they deliberately cool the gases as far as possible to extract most of the available energy from the combustion gases. As a result of the exhaust being "cool", they can use common PVC pipe for the exhaust duct. However, many have a small supplemental system to neutralize the acid in the condensate before it's dumped to the building's sewer system.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 5:44 pm 

Joined: Tue Jan 25, 2011 2:07 am
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OK, I think I caused the thread to officially 'jump the shark' by bringing up the Shay. But thanks to everyone for playing along, and thanks to Overmod for the very interesting reply. You guys really know this subject!


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 6:22 pm 

Joined: Wed Jan 23, 2008 6:12 am
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Location: North Wales and Australia.
If you where building a slow speed engine a shay type arrangement with double sided engines of triple compound is a good way to go. Such an arrangement is what I would have used on mount Washington if I'd built a new loco. The benefits of such a high speed engine would have been in overall efficiency.

As to heat in the exhaust gasses. Hugh is right in many ways especially with the chemical reactions. Steam from the cylinders is not that far a way from condensing. The heat from the exhaust gasses improve the condition of the steam to a dryer state where higher terminal velocities can be achieved. This aids the vacuum created.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Fri Aug 02, 2013 9:17 pm 

Joined: Sun Aug 22, 2004 7:19 am
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Thank you Nigel - that was my gut feeling, but I wasn't sure.......

I think there's a balancing point between what you can get out of both the steam and hot combustion gasses before you reach a point of diminishing returns and unforseen cross-consequences.

dave

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 3:29 pm 

Joined: Thu May 24, 2012 1:37 pm
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> If you were building a slow speed engine a shay type arrangement
> with double sided engines of triple compound is a good way to go.
> Such an arrangement is what I would have used on mount Washington
> if I'd built a new loco. The benefits of such a high speed engine
> would have been in overall efficiency.

OK, I'll bite. Exactly how would you run the driveshafts on a double Shay? How would you coordinate the speeds of the engines on curves? Why would you have triple compounding even at 0 psig unless your initial pressure was far more colossal than any Shay would merit... and with a tiny little lateral space for the boiler barrel, between those hulking LP cylinders, too. Have modern materials made a Thuile boiler practical?

Unless I'm mistaken, he's talking about EIGHT CYLINDERS on this locomotive, with the big ones at the ends of the shafts, as on marine engines. That's an awful lot of mains and rods and valves for an engine that won't run fast and that has its gears outboard of its bearings...

If you want the geared effect with little wheels, a Heisler is better (and perhaps more tolerant of triple expansion clearances!). A bit larger in the wheels, and you have an application for a Besler locomotive. Larger still and you can provide the 19 1001 type of individual-axle drive -- if you want a 'Shay' type, put one V2 on each "bogie' and use gears or shafts to the axles, rather than one on each driver...

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 4:24 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5233
Location: southeastern USA
Robnert, I've worked on Shays and Heislers and the Shay is by far the easiest one to keep running. Everything is where you can reach it. If the drive shafts work on one side, why not on both? There's no shortage of built-in slop to keep them happy as they experiment with the limits of their U-joints and sliding telescoping square shafts while the trucks follow the wavy light rail through the woods.

The boiler question is on my mind......although a good superheat before the first expansion and some subsequent reheating could take some care of that.

dave

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 4:40 pm 

Joined: Fri Mar 05, 2010 3:41 am
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Location: Inwood, W.Va.
This thread is taking some most interesting turns, particularly in the form of the locomotives that might be proposed--and their presumed service cycles.

Much has been talked about in regard to the classic Stephenson locomotive. In a way this is a continuation of the work of la Porta and Warsdale. Some of these locomotives would be intended to mesh into current diesel operations, others might be intended for secondary services, such as a proposed 2-6-2 for excursion service that I could also imagine handling branch line freight trains.

We've also had some talk about Shay type locomotives. These were normally thought of as industrial (logging) engines, but it may be recalled that main line railroads bought them too for special situations (the largest owner of 150-4 Shays--150 tons, 4 trucks--was Chesapeake & Ohio), and such a special situation was the cause of the last Shay to be built--Western Maryland No. 6.

Lima was also looking at one point at a huge 4-truck Shay built specifically for hump service. The monster would have had a configuration closer to that of a Garrett than a traditional Shay, and if my memory is right, would have had a tractive effort rating on the order of 98,000 lbs!

Dang! I just put my copy of Hirmisaki's Lima history back downstairs. . .


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 4:45 pm 

Joined: Fri Mar 05, 2010 3:41 am
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Location: Inwood, W.Va.
Just remembered something else--the last three Leslie rotary snowplows built were constructed under license by Lima (Alco being out of the steam business by then), and they incorporated two Shay engines to drive the cutting wheel. If two Shay engines could be used in a rotary, why couldn't they be used on a large hump or special locomotive?

Isn't at least one of these rotaries, a Union Pacific one, still around, and still with its steam engines and boiler intact?


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 5:37 pm 

Joined: Tue Jan 25, 2011 2:07 am
Posts: 328
With respect to steam turbines, I just read over the Wikipedia entry, "steam turbine locomotives" and learned a few things.

The GE steam turbine-electric loco built in 1938 was pretty interesting. It was a condensing steam loco, and essentially a "mobile power plant". It didn't work out for the UP for some reason (I would love to learn why). But according to a source cited, the Great Northern found it satisfactory:

WIKIPEDIA wrote:
" The GE turbines were used during a motive power shortage on the Great Northern Railway in 1943, and appear to have performed quite well. However, by the end of 1943, the wheels of both locomotives were worn to the point of needing replacement, and one of the locomotive's boilers developed a defect. The locomotives were returned to GE and dismantled. "

Source: Lee, Thos.R.:"Turbines Westward",page 9,T.Lee Publications,1975, ISBN 0-916244-01-6

Who wouldn't mind seeing one of these pull a mainline excursion today?

(Image courtesy Wikipedia)


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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 6:24 pm 

Joined: Wed Jan 23, 2008 6:12 am
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Location: North Wales and Australia.
In the case of a MW Shay it's very convenient. The right had engine drives forward to the front axel and the left engine to the rear. You need at least a five to one gear ratio and you put that in the end of the axel cradle which also houses the brakes and other rack stuff. You can actually have suspension which the originals don't have. The axel unit would be a convenient bolt in unit. The drive is purely through the cog on the centre of the axle and the wheels are lose on the axle so wheel slippage is not an issue

The cylinder units would also be a bolt on unit. I can't remember off hand but the originals had less than ten inch cylinders so with three per side, higher boiler pressures (250psi?) then at lest compounding is practical. The cylinder speeds can be high with properly worked steam flow which again makes compounding worth while. Your not talking about marine practice but more towards internal combustion practices, although it would be still double acting. The actual size of the cylinders is small maybe even the third one being no more than 6 inch diameter. With these arrangements the drive system can be keep out of the dirt as its all up higher than the original arrangement. The shafts and drive gears although lower can all be built into cases so removing the dirt and preventing grease going every where.

The boiler with standard gauge would have way over three feet width nearer four so would have had a 10 sq ft grate which is over what is required. You could easily build in super heat and reheat. We had a feed water heater on MW 9 and I believe others where done after I went? And that was very worth while so I would have included that also.

Why a Shay? Where ever I have worked with engines from rack to Garratts it's always you want things out side rather than inside. Doing heavy engineering from a pit with hands squeezed up in some un reachable place is not pleasant. For combustion work shafts and racks passing along and under the fire box is just a nightmare both practically and design wise. You want that area clear of every thing that dose not have to be there. Hieslers and Climax both have this issue so some extent. Currently it's so nice to be working on a type of loco which only has the v of the trailing truck anywhere near the firebox and burners.

With the cog you don't want the two engines locked together as the wheel base has to match the pitch of the rack and that's variable and in Abt systems you keep the wheel base short to avoid the problem. Even if your talking about a shay for the forestry you will have wheel slipping to go round any corner. For the two separate engines it would be no different to driving a Garratt.

With both what I have described of this Shay type and the 2-8-2 they are machines which if opportunity had or could occurred would have been both an evolution and radical in where they could or should be developed. I make no claims that they solve every problem, it's finding the best compromise to move on which is what is needed. More than ever hardware is required to prove the evolution is still possible. That is why in some ways even some of the headline projects are still not enough. Something like the 2-8-2 needs to be done simply to make a lasting statement for our generation. We can talk here of endless concepts and endless debates about what is best and our dreams but unless the money is there to make it reality then it's just dreams and the dream is to actually have the money to make or dream come true.

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Last edited by Nigel Anthony Hewer Day on Sun Aug 04, 2013 6:36 pm, edited 1 time in total.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 6:28 pm 

Joined: Wed Jan 23, 2008 6:12 am
Posts: 179
Location: North Wales and Australia.
FLO wrote:
With respect to steam turbines, I just read over the Wikipedia entry, "steam turbine locomotives" and learned a few things.

The GE steam turbine-electric loco built in 1938 was pretty interesting. It was a condensing steam loco, and essentially a "mobile power plant". It didn't work out for the UP for some reason (I would love to learn why). But according to a source cited, the Great Northern found it satisfactory:

WIKIPEDIA wrote:
" The GE turbines were used during a motive power shortage on the Great Northern Railway in 1943, and appear to have performed quite well. However, by the end of 1943, the wheels of both locomotives were worn to the point of needing replacement, and one of the locomotive's boilers developed a defect. The locomotives were returned to GE and dismantled. "

Source: Lee, Thos.R.:"Turbines Westward",page 9,T.Lee Publications,1975, ISBN 0-916244-01-6

Who wouldn't mind seeing one of these pull a mainline excursion today?

(Image courtesy Wikipedia)

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 6:30 pm 

Joined: Wed Jan 23, 2008 6:12 am
Posts: 179
Location: North Wales and Australia.
Nigel Anthony Hewer Day wrote:
FLO wrote:
With respect to steam turbines, I just read over the Wikipedia entry, "steam turbine locomotives" and learned a few things.

The GE steam turbine-electric loco built in 1938 was pretty interesting. It was a condensing steam loco, and essentially a "mobile power plant". It didn't work out for the UP for some reason (I would love to learn why). But according to a source cited, the Great Northern found it satisfactory:

WIKIPEDIA wrote:
" The GE turbines were used during a motive power shortage on the Great Northern Railway in 1943, and appear to have performed quite well. However, by the end of 1943, the wheels of both locomotives were worn to the point of needing replacement, and one of the locomotive's boilers developed a defect. The locomotives were returned to GE and dismantled. "

Source: Lee, Thos.R.:"Turbines Westward",page 9,T.Lee Publications,1975, ISBN 0-916244-01-6

Who wouldn't mind seeing one of these pull a mainline excursion today?

(Image courtesy Wikipedia)

I would have loved to see these working.

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 Post subject: Re: Ultimate High Tech Steam, what would you build?
PostPosted: Sun Aug 04, 2013 7:01 pm 

Joined: Thu May 24, 2012 1:37 pm
Posts: 870
Thanks, Nigel.

I have what may be a better idea for the drive -- assume for the moment that we use splined driveshafts (with boots) and not square ones.

Use spiral bevel gears, with bearings both sides of the 'ring gear' and straddle pinions, and then use quill drive to the wheels similar to what 19 1001 did. This keeps the gearing accessible, reduces road shock and thrust through the gear train, reduces unsprung mass, and permits easy lateral accommodation and, to an extent, cross level accommodation. You'd want to ballast the 'other' side of the truck frame, but I'd put brake gear and the like over there (with secondary reservoirs a la Leader mounted on the trucks).

Good point about orienting the driveshafts away from the combustion or ash zones.


My understanding of the GE steam-electric problems was (1) condenser choked early and often in hot weather; and (2) locomotives were underpowered for their size and complexity, given the constant-HP nature of the electric transmission. Yes, I'd expect their performance to be better at high altitude in a cooler environment, at relatively low speeds where the continuous rating of the traction motors would give best advantage. But just about EVERYTHING on these locomotives was probably unfamiliar to maintenance forces.

Detail design by GE appears to have been sensible. Look at the size and volume of the exhaust plenum! Any trouble with the boiler control in the early Forties would have long ago been solved.

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