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HO Scale "Big Bad John" B-D-B+B-D-B Bipolar Diesel Boxcab

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Posted by gmpullman on Thursday, March 15, 2018 8:48 PM

mbinsewi

 

 
tedtedderson
Live off the P's dime as long as you can!

 

Well, that's just wrong.  

Mike.

 

 

 Teen by Edmund, on Flickr

Laugh  Ed

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Posted by mbinsewi on Thursday, March 15, 2018 8:39 PM

tedtedderson
Live off the P's dime as long as you can!

Well, that's just wrong.  

Mike.

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Posted by tedtedderson on Thursday, March 15, 2018 5:36 PM

NWP SWP

I didn't dig up this thread! Right now I'm working on an A-B-A set of P42s.

Lawn business, joint chiefs (my parents) said I can't start a business or even get a learners permit to drive till graduation. So I am stuck till late April early may.

 

Nah this was my bad. I skimmed and missed the "I'm working on a different project" response. 

Lucky for me there's still a little snow and my grass is still brown! 

Live off the P's dime as long as you can!

T e d 

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Posted by NWP SWP on Thursday, March 15, 2018 5:21 PM

I didn't dig up this thread! Right now I'm working on an A-B-A set of P42s.

Lawn business, joint chiefs (my parents) said I can't start a business or even get a learners permit to drive till graduation. So I am stuck till late April early may.

Steve

If everything seems under control, you're not going fast enough!

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Posted by maxman on Thursday, March 15, 2018 4:59 PM

richhotrain

 

 
tedtedderson

Any updates on this project?  Seems like this is going to be a mean machine! 

T e d  

Oh boy.  ConfusedConfused

Rich

This is like the Whack A Mole game.  Every couple days a new, figment of the imagination from an idle mind, mole is shoved up through one of the arcade game holes and everyone who should know better wastes time responding.

As someone else said, there are lawns out there that need mowing.

I'm sure there are contrary opinions.

 
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Posted by richhotrain on Thursday, March 15, 2018 3:56 PM

tedtedderson

Any updates on this project?  Seems like this is going to be a mean machine! 

T e d  

Oh boy.  ConfusedConfused

Rich

Alton Junction

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Posted by tedtedderson on Thursday, March 15, 2018 3:13 PM

Any updates on this project?  Seems like this is going to be a mean machine! 

T e d 

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Posted by Overmod on Wednesday, January 24, 2018 2:38 PM

Clutch_Cargo
That's two independent locomotives coupled together.

And two of the very first practical mainline diesel locomotives in North America (or, really, anywhere).  Notable among many things for the use of relatively lightweight dirigible engines in an era when compression-ignition engines and their peripherals were generally too heavy for their horsepower even when giving full allowance for adhesion ballasting.

Baldwin had a relatively similar design (1500) at right around this time, and Clessie Cummins in his autobiography indicates some of the excitement in road-diesel development up to the late 1920s.  An important detail, though, is how very different the successful EMC/EMD "locomotive" designs were from these, and not incidentally how the whole of electric locomotive design switched within just a few years from heavy cast underframes to trucks and span bolsters...

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Posted by Clutch_Cargo on Tuesday, January 23, 2018 1:07 PM

NWP SWP

Here's another possible inspiration...

 

That's two independent locomotives coupled together. CNR 9000/9001

http://www.trainweb.org/oldtimetrains/Various/early_diesels.htm

CC

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Posted by NWP SWP on Monday, January 22, 2018 5:31 PM

Here's another possible inspiration...

Steve

If everything seems under control, you're not going fast enough!

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Posted by NWP SWP on Tuesday, January 9, 2018 6:22 PM

Not at the moment now working on another project... I sent you a PM if you would like to discuss it...

Steve

If everything seems under control, you're not going fast enough!

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Posted by ATSFGuy on Tuesday, January 9, 2018 6:19 PM

Still working on that mockup?

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Posted by tstage on Saturday, January 6, 2018 4:01 PM

Okay.  How 'bout making a full mockup of the entire shell in that current scale then the exact same thing in HO.  That would be a start...

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by NWP SWP on Saturday, January 6, 2018 3:57 PM

Here's the mock up... it's not to scale but is a good example of what I'm going for...

Steve

If everything seems under control, you're not going fast enough!

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Posted by NWP SWP on Saturday, January 6, 2018 2:10 PM

I was thinking getting four Athearn Alco PB shells, using the roofs from two to make the fronts of the cab and use the other two as the rest of the shell.

I made a paper mock up and I'll post a picture in a bit...

Steve

If everything seems under control, you're not going fast enough!

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Posted by ATSFGuy on Saturday, January 6, 2018 10:10 AM

Hello all,

You clearly need a rectangular shell for the body, have you given some thought about what you what to use and how are you going to attach it to the wheel frame/chassis.

What wheel arrangement did you want?

Can you try to "kitbash" a shell you want to use and post a picture so we can see it?

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Posted by rrinker on Tuesday, January 2, 2018 10:53 AM

 Actually, if you look at the Wikipedia entry that picture comes from, it zooms in many times, and it becomes evident that the B and D trucks link at the pin the goes to the carbody. There is nothing shown in the diagram linking the D truck frame to the carbody. The two D trucks are linked in the middle, but ther is nothign supporting the middle section of the carbody. It appears the middle section is carried suspended by supports that project out from each of the end carbody units.

                             --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Overmod on Tuesday, January 2, 2018 9:48 AM

Watch it, because the Bs need their Bissel steering axles to 'do right' with the inline articulation.  And a span bolster there doesn't help anything; it's meant for two 'unhanded' Adams-style trucks that pivot around their defined centers, to get TE up to pins on the chassis without binding while spreading the imposed load.

The bipolar underframes (and most other lightweight composite GE underframes) REQUIRE the Batchelder drive in order for them to be that light, as no other system provides so little need for heavy or closely-aligned paraphernalia in the underframe structure.  If you converted to nose-suspended motors, you'd need to find room adjacent to the axle for the whole armature, field, case, and support; you'd need machined bearings on the axles and on the frame pivot points; you'd probably need to revise some of the transoms and other construction in the trucks that was specific to the vertical-pole-piece fields and brushholding arrangement for the Batchelder motors.  In a word, this would NOT be a wise alternative.

There is no reasonable alternative with frame-motored geared quill drives at this wheel size.

That leaves some kind of conversion with one of the flexible axle drives you can see contemporarily described in the Ransome-Ellis Encyclopedia of World Railway Locomotives -- still a lot of tinkering.  Having a 'monomoteur' arrangement is going to interfere, substantially, with the prime mover and fuel arrangements 'above deck height'. 

In other words, all the economies that go with adaptive reuse of the old bipolar underframe probably involve retaining the Batchelder drive, although you could at least think about modifying it to reduce some of the effects of lateral moment.  Right at the moment you decide on a re-motoring, you should go straight to using something like weldments for the truck frames and chevron springs on the axles, as on the GM10B (which is one-and-a-half AEM-7s with freight gearing, with all the successes and problems you'd expect from such an idea).  Of course a better solution still would be a combo of the GM6 underframe (hint: it's not difficult to model in HO) and the Conrail dual-mode-lite project from the early '80s ... but those look much like normal locomotives, albeit something for which there is a modeling lacuna at present.

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Posted by NWP SWP on Tuesday, January 2, 2018 9:22 AM

Ok the two B-D-B sets have  span bolsters and what would be a better drive for the unit than the Batchelder?

Steve

If everything seems under control, you're not going fast enough!

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Posted by Overmod on Tuesday, January 2, 2018 8:42 AM

Part of the problem is that there is no convention, as Wiener attempted to do for articulated steam locomotives, for various methods of chassis articulation in electrics.

A GG1 (which of course is 2-C+C-2 since it follows the German system used for electrics, and counts axles instead of wheels) gets its "+" by analogy with Wiener because all the buff and draft goes through the underframes.  But by the same analogy it is difficult not to accord, say, a steam Challenger the same courtesy (which in expanded Whyte notation would then be 4-6+6-4, something that raised howls when le Massena and Trains tried it a few decades ago in a manner that always reminded me vaguely of Roosevelt's 'simplified spelling' push.  [The nominal difference being that the boiler on a Mallet/simple articulated is rigidly mounted to the engine nearer the firebox, with the other hinged to it essentially as a compound Bissel, whereas the G and similar electrics 'float' the carbody with a pin at one end and centering slide at the other].  I remain mystified where that intercalated center "B" truck comes from; the poor thing would have to take a significant portion of TE either way, would have flange wear out the wazoo from being relatively unstable (laterally and in yaw, to start) in buff conditions, and contributes no useful added flexibility for carbody attachment that, say, a span bolster over the two D trucks would provide.

I have had remarkably little success finding a 'postable' online reference that actually shows the articulation and equalization scheme for the EP-2s, and my memory isn't adequate to do so definitively.  The best drawing I could find (the one on Wikipedia being apparently taken from a book and not very clear) was linked by Mr. Rinker in a post here from 2010:

but this does not show the actual articulation between the B and D trucks in a way I can read, and similarly does not show the equalization differences at the two ends.  Someone please interpret the drawing if it shows the detail.

If I recall the setup correctly, the underframe is continuous and would therefore best be notated 1-B+D+D+B-1; the end units correspond to 2-4-0s (and the outer ends of the two 'hood' parts of the carbody attach to them) which then guide the outer ends of the two D trucks through multiaxis ('ball-and-socket') joints.  We are I think all agreed that the inner ends of the two D trucks have a similar joint.

One reason these composite underframes can be so light in construction (compared to later locomotives with cast underframes) is that the joints provide cross-level articulation as well as hinging.  This requires less work from the articulation to provide stable running (as for example on any modern simple articulated since the N&W A by design and any Alco Challenger by convention by removing any vertical compliance from the hinge) and of course the gearless motors did not require very stable alignment of multiple points in the chassis.

Meanwhile part of the 'rest of the story' is that more modern versions of electrics used what are basically 'repurposed diesel-electric trucks' - B trucks on the late mega-electric designs, and trimount Cs on just about anything after that, including the N&W TE-1 STE.  Some of these designs use span bolsters between pairs of trucks, and we need a consistent notation for those vs. fully articulated chassis, but some use the sort of funky lateral linkage you find under B-B-B locomotives without hinged carbodies ... where each outer truck has a conventional Adams-style pin, and define the motion of the inner truck to stay parallel to the carbody but slide sideways, in some cases over 11", on curves.  Those have a torque strut or similar connection to the carbody and hence have no "+".

If someone has a good diagram of the exact type of pin and sliding joints used in the carbody supports on the EP-2, for both the outer and inner articulated-carbody units, it would probably help the OP assess his carbody design a bit better.  It will need to be rather extensively modified if he wants to accommodate two medium-speed engines/generators, for reasons I will PM him to avoid MEGO on the forum.

I have yet to see the 'imagineering' that is used to justify using the Batchelder drive for freight service; it was much better suited to contemporary passenger service (and, in fact, still would be; a strong case could be made that the EP-2s would have essentially outlasted the need for electric passenger service itself on MILW had the last four unit rebuilds been done better, which is a significant engineering accomplishment for a design from 1919).

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Posted by rrinker on Tuesday, January 2, 2018 6:50 AM

 I hate to say it, but a loco that long would HAVE to have some articulation. A rigid wheelbase that long would NEVER negotiate curves. The pair of B trucks in the middle only make sense if articulated. Even a single truck between the two big ones is odd so as it is, two of them without articulation would serve no purpose - might as well make is B-D-D-D-B in that case. In PRR style, if it were a 4-D-2+2-D-4 would make it an MM class. Like the GG-1 was 4-C+C-4 and the DD-1 was 4-B+B-4.

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Mheetu on Monday, January 1, 2018 10:02 PM

 

More like this?

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Posted by NWP SWP on Monday, January 1, 2018 9:48 PM

Maybe I should be saying B-D-B-B-D-B thats a 2 axle, 4 axle, 2 axle, 2 axle, 4 axle, 2 axle...

I think the plus means articulated doesn't it, if so no that's not what I'm going for... thanks for the cooperation...

Steve

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Posted by Mheetu on Monday, January 1, 2018 9:43 PM

 

So you need trucks like these then?

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Posted by NWP SWP on Monday, January 1, 2018 9:36 PM

That's getting close just it's going to have a B-D-B+B-D-B wheel arrangement...

Steve

If everything seems under control, you're not going fast enough!

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Posted by Mheetu on Monday, January 1, 2018 9:34 PM
not sure if it work https://image.ibb.co/co5XUw/Possible_P2_with_Bi_Polar_Mix.jpg
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Posted by NWP SWP on Monday, January 1, 2018 8:57 PM

Mheetu, I don't see anything other than a image that says "free screenshot capture"

Steve

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Posted by Mheetu on Monday, January 1, 2018 8:54 PM

Base on what you have given in information this is what i think your locomotive would look like 

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Posted by NWP SWP on Monday, January 1, 2018 2:13 AM

Ok the body will resemble the second locomotive, I'm not sure though whether to build it with porches on both ends like the second or put a porch on the front but have the body go to the back like the first and maybe build a second unit or tender...

Something I want to clarify is there will be two "decks" that are essentially boxes that have half the trucks attached to each...

Steve

If everything seems under control, you're not going fast enough!

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