Big Bad John Locomotive

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Posted by tdmidget on Wednesday, January 10, 2018 10:21 PM

NWP SWP

Well the NWP-SWP System runs from New Orleans to the west coast all the way to the top then on to Chicago...

Could theoretically jet turbines be used in the locomotive? Being fueled by aviation fuel?

Overmod, I really appreciate your help, but some of the stuff your saying is going over my head could you try to explain your ideas in layman's terms?

 

NWP SWP

Well the NWP-SWP System runs from New Orleans to the west coast all the way to the top then on to Chicago...

Could theoretically jet turbines be used in the locomotive? Being fueled by aviation fuel?

Overmod, I really appreciate your help, but some of the stuff your saying is going over my head could you try to explain your ideas in layman's terms?

 

"jet turbines"? grow up. This is not the fifties with the love affair with the word "jet". here is a "jet turbine locomotive":

https://www.pinterest.com/pin/383650461988036101/

It it is driven by a shaft , it is not a jet in any shape or form. It is a "combustion turbine" in the common usage of "gas turbined". Steam is a gas so all steam turbines are "gas" turbines. Combustion turbines do not require aviation fuels. Such fuels are spec'd with such factors as extreme cold and ability to start under extreme conditions. If you were paying attention you would know that such locomotives have been tried by Union Pacific. They did not require aviation fuels. They were not "jet turbines".

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Posted by SD70Dude on Wednesday, January 10, 2018 10:35 PM

NWP SWP

Could theoretically jet turbines be used in the locomotive? Being fueled by aviation fuel?

Jet fuel is indeed very similar to kerosene but turbines can easily run on pretty much any liquid fuel (and there have been experiments with pulverized coal or coal slurry), historically the most common turbine locomotive fuel has been heavy residual oil (thick tar-like Bunker C grade).  The reason for this is simple:  It was dirt cheap, to the point of being almost free, and this made up for the turbine's monstrous appetite (the UP turbines consumed roughly DOUBLE the fuel volume that diesels of equivalent power would burn).

As I said this did not matter at first but eventually became the turbines' downfall, as refineries found new markets for residual oils (especially in the plastics industry) their price went up, and turbine locomotives became uneconomical to operate.

But this would not have been an issue in the 1950s, and there is plenty of room in your boxcab for both a turbine and an auxiliary diesel engine, which is very useful in both starting the turbine and moving the locomotive around shops & yards (UP once got to replace all the windows in a roundhouse after someone started one of the turbines inside).

UP also investigated using propane as a fuel, carried in a pressurized tender.  The turbine actually ran better on propane (clean burning, no soot or ash like with heavy oil) but refueling was difficult and time-consuming, and there were safety concerns about carrying that much propane right next to the locomotive (I wonder how that would play out in today's world of LNG tenders?).

Coal-fired turbines never did get around the problem of ash destroying the blades.

An additional problem is that turbines are incredibly inefficient at idle, burning nearly the same amount of fuel as they do at full throttle.  This is why the auxiliary diesel engine was used to move the locomotive when it was running by itself.

I can boil my ramblings down to this:  A turbine powerplant makes sense if your #1 priority is raw horsepower, and/or your railroad wishes to use a fuel other than diesel.  Otherwise a multi-engined diesel makes more sense.

Greetings from Alberta

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Posted by Overmod on Thursday, January 11, 2018 2:27 PM

SD70Dude
I can boil my ramblings down to this: A turbine powerplant makes sense if your #1 priority is raw horsepower, and/or your railroad wishes to use a fuel other than diesel. Otherwise a multi-engined diesel makes more sense.

Steven: note tdmidget's comments carefully (he is knowledgeable about power turbines).  The correct term for what you're using is turboSHAFT engines, and there are much more 'likely' designs today than there were in the era you're wanting to model, with a host of issues including the ones already mentioned.

One great promise of relatively small turboshaft engines was that their relatively small size and light weight  would allow them to be packaged in lightweight passenger trains -- that is NOT your concern here.  Neither is the idea of using alternative crap fuel like #5/#6 in an expensive and finely machined Brayton-cycle device, without effective regeneration or even cost-effective applicability of combined-cycle equipment.  One important priority of railroad economics is to keep the cost of fuel down; another is to minimize the absolute fuel consumption (by extension in modern practice with SCR, 'fluids consumption'); yet another is to have fuel that is relatively immune to fires or accidents in handling.  I have never thought of any of these things applying to gas turbines burning some weather-tolerant version of Jet A.  Unless you arrange your turbines to burn diesel, you'll have to arrange ... and staff ... and maintain ... alternative fueling facilities, including emergency response capability, for the alternate fuel, and it is likely only a matter of time before the wrong fuel makes its way into a consist of the other kind of engine.  This may not be catastrophic in the YouTube video sense, but a consist that may require a full purge of what may be gelled fuel is not a happy thing, even once.

I tinkered around with the idea of stuffing an E-unit shell with a bunch of PT6 gensets in modular frames, with the idea I could start and stop some of them to approximate the output of Essl's locomotive (and use the additional power in something like MATEs with fuel bunkers).  This was pretty well given the kibosh after the oil-price shenanigans in 1973, similar to what shut down effective development of gas turbine power in rail applications almost anywhere else.  There are other reasons not to use them 'on the ground' in a high-vibration environment subject to over 180g of instantaneous shock, but we don't need to take them up if the idea is already a non-starter economically.

One thing that at least in theory favors a combustion turbine over a compression-ignition engine is that the fuel they use can be less refined with lower need for additives.  Modern diesel injectors involve close tolerances and special coatings; if you have experience with light diesel trucks you will already know about stuff like Stanadyne and reasons for its use.  Turbines can be made to run on just about anything that can be run through simple injectors with adequate heat release and reaction time characteristics ... the Chrysler turbine-car development program made the interesting comment that the engine would happily run on Chanel #5, which if nothing else proves some engineers have a good sense of warped humor.  This is common to light-oil firing in steam locomotives: you can cut quite a few steps out of the production process otherwise needed for diesel fuel or 'biodiesel' and still have something that works quite nicely and reliably.  Of course, you then need a production and distribution infrastructure for the lower-cost fuel -- a point upon which many alternative-fuel schemes have foundered.

See the earlier discussions (related to restoring a UP 8500 turbine set) concerning gas fuel.  Personally I don't think much of LPG or CNG, and while it is possible to inject LNG into engines it is NOT something that typical lowest-cost railroad power is likely to find valuable (as tdmidget indicated, most of the working schemes to burn it involve vaporization of the liquid, ideally with 'regeneration' heat, before combustion).  I could tell you a reasonable alternative to free-piston generation of the 'typical' 1950s sorts ... but it is likely to produce even more problems for the neighbors than 'hot starts' of the UP turbines did Wink

(erikem: do you think he might get more benefit than he would out of the Oxford catalytic cycle if he tried this as fuel for a high-horsepower engine?)

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Posted by SD70Dude on Thursday, January 18, 2018 1:36 PM

How is work going on your design Steven?

Greetings from Alberta

-an Articulate Malcontent

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Posted by NWP SWP on Thursday, January 18, 2018 1:49 PM

Well I have shifted to work to smaller projects but I'm still working on it...

I was thinking could F unit style B trucks be made into Ds? Dropping the bipolar concept all together... then if I go full length body (not my first choice) I could drop the decks and use a taller PM like the FM OP PMs...

I'm really thinking high drivered fast freight units... that goes in sync with what got the ICC to approve the first early mega merger which formed my road the ability to move freight more efficiently from point to point with minimal delays... 

Steven

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Posted by Overmod on Thursday, January 18, 2018 2:23 PM

NWP SWP
I was thinking could F unit style B trucks be made into Ds?

No.  For further detail look up Martin Blomberg's truck designs for GM and see how they are constructed. 

You could use these B trucks with span bolsters as multiple B trucks following the Westinghouse proposal.  The 'catch' is that much of the flexibility of this truck design needs to be tinkered with (one major place to start being the springing between the bolsters and the swing hangers) and it is in my opinion difficult to arrange a modern zero-weight-transfer equalization arrangement (as for example on the GE FB2, or any of the modern trucks with traction struts doing the actual longitudinal power transfer at motor-suspension-hinge height) -- I believe it may be relatively cheap to get older GEs that have those trucks and update any of the little rubber pieces in them that may have degraded.

Personally I wouldn't use a D truck at all; not only do you have a substantial investment in special castings, you have all sorts of issues with lateral compliance that are only incompletely solved with the Flexicoil design.  I'd think long and hard before not using a good radial-steering C truck, probably an older HTCR, with Jawn-Henry-like span bolstering, if you go with separate bogie trucks.

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Posted by SD70Dude on Thursday, January 18, 2018 2:30 PM

NWP SWP

Well I have shifted to work to smaller projects but I'm still working on it...

I was thinking could F unit style B trucks be made into Ds? Dropping the bipolar concept all together... then if I go full length body (not my first choice) I could drop the decks and use a taller PM like the FM OP PMs...

I'm really thinking high drivered fast freight units... that goes in sync with what got the ICC to approve the first early mega merger which formed my road the ability to move freight more efficiently from point to point with minimal delays... 

I don't believe there is any advantage to taller driving wheels when using traction motors, if a higher top speed is desired one can simply change the gear ratio between motor and axle.  As an example E-units geared for 120 mph used the same size wheelsets and traction motors as F-units and Geeps in freight service. 

The F-units used Blomberg trucks, which I don't believe have ever had a 4-axle version made.  A 3-axle version was though (this is what E-units rode on), and it did not provide room for a traction motor on the middle axle.  A better (simpler) solution would be to use a span bolster to join two Blomberg B's together, this would use existing parts and put less stress on the track, as rigid "D" trucks do.

EMD's first "D" truck went into production in 1963, on the DD35s for Union Pacific, and was a modified version of the Flexcoil, which to put it mildly is not known for its ride quality at high speeds.  UP was not impressed with the tracking abilities of the "D" truck when leading at first, and ordered additional GP35s to be run ahead of the DD's. 

Greetings from Alberta

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Posted by Overmod on Thursday, January 18, 2018 2:55 PM

SD70Dude
UP was not impressed with the tracking abilities of the "D" truck when leading at first, and ordered additional GP35s to be run ahead of the DD's.

Don't you mean the 'Fast Forties'?  Those were intended to be leading because the conception of the DD35 was originally not to have a cab, or so I thought.  There is a little additional lateral guiding to be provided with an equivalent-geared unit pulling the frame of a DD into a curve, but it won't really help with any of the guiding dynamics of the truck itself, which as I recall was the 'issue' with those things.

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Posted by NWP SWP on Thursday, January 18, 2018 2:56 PM

How about something like the GN Z-1 or like the GN W-1 or MILW Little Joe?

Steven

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Posted by Overmod on Thursday, January 18, 2018 3:01 PM

... which leads me to wonder whether Steven might want to reconstruct the triple-unit (Fast Forties either side of a really, really big bad booster) or perhaps go over to Sam Berliner III's delightful pages to see what a really, really big cowl unit looks like [:-O]

The problem in the long run is that very, very few things can couple to a HO-scale DDanything on typical model curves and still provide meaningful tractive effort to the 'appropriate' consist; he's much better off sticking to a fully-articulated underframe for all the old valid reasons folks used them back in the day.  The idea is to have 'bad' only be half a word, not a Baldwin-like synonym for operating reliability...

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Posted by SD70Dude on Thursday, January 18, 2018 3:08 PM

Overmod
SD70Dude
UP was not impressed with the tracking abilities of the "D" truck when leading at first, and ordered additional GP35s to be run ahead of the DD's.

Don't you mean the 'Fast Forties'?  Those were intended to be leading because the conception of the DD35 was originally not to have a cab, or so I thought.  There is a little additional lateral guiding to be provided with an equivalent-geared unit pulling the frame of a DD into a curve, but it won't really help with any of the guiding dynamics of the truck itself, which as I recall was the 'issue' with those things.

When UP first ordered the DD35-GP35 sets there were concerns about the "D" truck leading, that is why EMD designed the sets with the GP35s leading.  It seems the concerns turned out to be unfounded as the later DD35As and Centennials led for years without problems. 

I should have used better wording.

Greetings from Alberta

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Posted by Overmod on Thursday, January 18, 2018 3:11 PM

NWP SWP
How about something like the GN Z-1 or like the GN W-1 or MILW Little Joe?

The 5004 is the wrong picture: that's just an electric Mikado; no fun there no matter how many units you cobble together.  You mean the one with all the trucks under it ... and you could get the same effect, as you noted, with war-weary diesel-electric trucks.

You could certainly work with the chassis of a Joe a little bit later than the stated 'transition' era, as you could get 'em cheap after the Milwaukee electrification shut down.  I am not sure there would be much advantage other than prototype cheapness, though: you'd be paying top dollar for model chassis, and these were built for Russian exchange (note the spoked engine-truck wheels?) and might not be the best candidates for long-term maintainability (I don't remember what needed to be done to adapt them back to standard gauge; might have been just replacement axles with different wheelseats, but I think it was more involved than that)

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Posted by erikem on Friday, January 19, 2018 11:21 PM

Overmod

 (erikem: do you think he might get more benefit than he would out of the Oxford catalytic cycle if he tried this as fuel for a high-horsepower engine?)

 

Hmmm, I'd think he would be better off with Acetylozone (HOOOCCH)... I was aware of Amitol, which was a mix of O starved TNT and O surplus AN.

Getting to the topic of using the Bipolar underframes:

The bipolar motors were intended for relatively light duty, lacking commutating poles meant that commutation would be a problem with heavy overloads. What having  twelve motors was good for was allowing for a great flexibility in running speeds with running connections giving 250, 500, 750 and 1,000V per motor along with a field shunt position for each running notch. Overloads at lower voltages would ease commutation.

I have read stories about the bipolars being very flexible.

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Posted by Overmod on Saturday, January 20, 2018 11:24 AM

Note the recent comment in another thread about why the 2-D-2 S-motors survived so long in active service, for PC and afterward.

Yes, part of the plan for using these is to avoid high peak loading of the TMs either in acceleration or dynamic, sorta the opposite of how to use (or as N&W found out so dramatically with Jawn Henry, misuse) Westinghouse hexapoles.  I would argue that this goes hand-in-hand with conventional early-'70s wisdom about reducing engine emissions, though, by controlling the rate of engine speed increase to be monotone slow over many seconds (VW built one van with an insane dash pot arrangement that took over 30 seconds to get to WOT).  Note that this is NOT something in accord with relay-digital Woodward-governor Locomotive MU throttle control, and I do not think the usual enhanced-Ward-Leonard approach of restricting acceleration of engine crank speed between notches with increased alternator field is at all workable to reduce actual emissions on a compression-ignition engine.  So you have the equivalent of dashpots in the mechanical linkage to the actual rack that limit speed rise and hence steady-excitation traction current, just the thing for bipolar motors.  Remember that Apollos and Trailer-Jets and other period things on Alphabet Routes would not really need high accelerations to work, just unrestricted priority over the given segment of railroad...

My introduction to brush issues came during the darkest days of PC, at likely the lowest place of maintenance priority, when you could still find Alco HH engines and similar items of ancient history actively switching.  With each notching up to pull or shove would come interesting electrical noises and carbon-emission-spectrum light from underneath, followed by some fat sparking and flaming chunks falling onto the ties as brushes crumbled against spark-eroded comms.  After the first few moments of panic you realized this was SOP in wartime; it ran because it had to, until it wouldn't run any more, and then it would go to a deadline.  I thought then, and still do, that a lighter touch on these poor girls would have let them run much longer.  But the railroaders who had to get work done with them did not care.  Steven's railroaders should be trained and supervised to care.

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Posted by ruderunner on Sunday, January 21, 2018 6:46 AM

steven,. I'm curious why you seem to insist on having the trucks be of the same or similar design?  Do you wish to keep the drivers all the same size?

Why? Many of the prototype locomotives had different truck and wheel sizes.

Are you intending to power all axles on your model?

I think finding a couple d trucks from a GG1 and adding a Bloomberg b truck to each end would be simpler, you could theoretically try to gear the d and b trucks to match speed but personally I think id gut the gears from the b trucks and make them dummies.

That would get your management a readily available chassis with proven reliability.  Bang for the buck.

As for prime movers, going with bang for the buck again, I'd stick with EMD or alco. FM engines were trouble prone and GE wasn't really a player yet.

My understanding is you want to have a diesel and catenary? A dual power arrangement right? If so I personally don't see any way this could be done without a full length carbody. Two prime movers and the transformer will take a lot of length. The early electrical components weren't small, think of Eniac compared to your cell phone.

BTW, which sub forum did you post in on the mrr site?

Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction

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Posted by NWP SWP on Sunday, January 21, 2018 11:23 AM

Well I would like to use all the same trucks. (Call me ocd)

Would the 3/4 length carbody work?

And I posted in the MRR General Discussion subforum you might have to go a page or two back...

Steven

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Posted by NWP SWP on Sunday, January 21, 2018 11:26 AM

Steven

Crooner, Imagineer, High School Graduate, living with Aspergers, President of the Republica Pacifica micronation,  President of the NWP-SWP System.

Hook'em Longhorns! 

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Posted by ruderunner on Sunday, January 21, 2018 4:09 PM

ok found the other thread.  No offense but wow you're all over the board here.

I think this will be a fun and challenging project but I think you need a more defined idea of what you want to end up with. I'm having trouble determining what the finished product will be.

Getting there from here is pretty straightforward but you need to know where here and there are.

I'd like to see a nice drawing of what you'd like the final product to look like.  A good explanation of what use the locomotive will be for. No need right now for explaining management decisions other than to keep in mind the bottom line, both for the railroad pocket book and yours.

From what I gather so far, you want an articulated carbody? Is that correct? If so it may be easier to think about this as 2 permanently coupled locomotives, each on a bdb underframe. At this point, you can plan for As and Bs to make as big a locomotive as you wish.

Let's see what you got!

Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction

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Posted by NWP SWP on Sunday, January 21, 2018 4:22 PM

The car body is not articulate, two sets of B-D-B trucks ride on span bolsters which connect to the car body...

I will give the drawing a go just bear in mind my drawing skills are lacking...

Steven

Crooner, Imagineer, High School Graduate, living with Aspergers, President of the Republica Pacifica micronation,  President of the NWP-SWP System.

Hook'em Longhorns! 

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Posted by ruderunner on Sunday, January 21, 2018 5:42 PM

ok not articulated carbody.

Take your time on the drawing. A ruler and a circle template will be a help.  Being neat and tidy is going to be a requirement for the build, might as well start with a neat and tidy drawing.

Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction

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Posted by Overmod on Monday, January 29, 2018 6:47 AM

NWP SWP
The car body is not articulate, two sets of B-D-B trucks ride on span bolsters which connect to the car body...

You don't need span bolsters in that case; they add additional height and you still need to have the pivot at one end shift because the two sets of B-D-B have to be themselves articulated (not just drawbarred) for the thing to work.

GE was very clear at the time about why the carbody was split to follow the articulation, and I would advise that you keep the longest rigid section of the carbody you design close to that needed to support the engine, generator, and perhaps parts of the lube and cooling system without deformation.  

If you do stick with a long rigid boxcab, the pivots will be at the effective quarter points of the span.  That will involve keeping them closer to the relatively heavy center of the cab, with longer cantilevers to the cab ends.  This may be the all-time comical overhang on anything less than about 84" radius HO curves, but since all the buff, draft, and coupler swing go through the underframes this shouldn't affect how the model runs or pulls.  Just don't have curves in tunnels, or structure inside the helix of 'elevator' spirals between levels...

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