15" new build question

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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LIALLEGHENY
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15" new build question

Post by LIALLEGHENY » Sat Nov 05, 2016 7:00 am

So starting in January I am going to start a new build, a 15" gauge Hudson or Berkshire, and I'm leaning towards the Berk since there are several Hudsons already out there. The question is do I build 3" or 3.2" to the foot? 3.2" would be correct for 15" gauge , whereas 3" is 14-1/8" gauge. Any thoughts? or suggestions?

Nyle

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FLSTEAM
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Re: 15" new build question

Post by FLSTEAM » Sat Nov 05, 2016 8:17 am

Your Scale won't make much difference since your engine is going to be big, "Really Big". Your first question needs to be where are you going to run it? and more important what track standards are you going to build to.
3" or 5" scale?

John B.
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Shay drawings and castings

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Harlock
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Re: 15" new build question

Post by Harlock » Sat Nov 05, 2016 11:51 am

Much like some people build to 1.6" scale to be correct for standard gauge in 7.5" gauge, I don't see any reason not to since you're likely going to have to make everything from scratch anyway. The only reason I'd build in straight 3" is if there are existing castings you plan to use that are that scale.

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Re: 15" new build question

Post by Glenn Brooks » Sat Nov 05, 2016 6:40 pm

I think I would go with straight 3" scale also, partly because the math is easier to do for the many machining and parts fitting decisions you will be making. And 3" is probably easier to select appropriate size fastenings, rivets, bar stock etc.

Look forward to your build log when you get started!

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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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Re: 15" new build question

Post by Loco112 » Wed Nov 09, 2016 12:03 am

Men,

The reason I would want to build in 3.2" is because 15" is broad gauge for 3" scale. The actual gauge for 3" scale is 14 +1/4" gauge, that means to widen his loco to 15" gauge he has to find 3/4" to add to the width of his wheels, bore spacing, valve gear, frame spreaders, etc.. while making sure they clear and fit every other part. Not a simple task, and could require a huge number of changes, which would take him farther away from his intended semi-accurate replica locomotive.

Try to imagine the changes required to take an existing 3' gauge loco and remake it into a meter gauge (3' - 3+5/8" gauge) locomotive. Practically every part of the frame and running gear would need redesign, or widened,

When Seymour Johnson designed his 3" scale loco, he had to redesign every part on it, and always said its basically a new locomotive of his design.

Niles, Do you want to build a well known locomotive in replica and work from the original builders drawings, or design an original locomotive and have to create your own drawings to build it?

I am so excited for you and this is going to be a great project. I hope this turns out to be one of the "once every 50 years" great projects. I'll do whatever I can to help you.
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Re: 15" new build question

Post by Harold_V » Wed Nov 09, 2016 4:33 am

Loco112 wrote: The actual gauge for 3" scale is 14 +1/4" gauge,
Assuming standard gauge is 56-½", 3" scale gauge would be 14-1/8", not 14-¼".

Assuming that to be correct, determining dimensions from prototype drawings is a simple matter of multiplying dimensions by 26.55%

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Re: 15" new build question

Post by LIALLEGHENY » Fri Nov 11, 2016 6:01 am

Harold, wouldn't it be 26.66% ?

I go back and forth between 3" and 3.2". Ideally I would prefer 3.2" because is is correct for 15" gauge. Yes I am planning on building as close to the prototype as possible. (without making my head hurt). I expect that I will be fabricating most everything, rather than making patterns and using castings. The only reason to stay with 3" would be that any of the castings I have seen for trucks , couplers, etc are for 3". I guess that doesn't really matter though.
As far as where to run it? I'll work that out when I'm done building. I think I'll have plenty of time to address that issue.

Nyle

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Re: 15" new build question

Post by Harold_V » Fri Nov 11, 2016 4:14 pm

LIALLEGHENY wrote:Harold, wouldn't it be 26.66% ?
My math dictates it's 26.55, but that's rounded up from 26.54867. Did I screw up?
15" divided by 56.5"

Harold
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Re: 15" new build question

Post by LIALLEGHENY » Fri Nov 11, 2016 6:21 pm

Actually , no you didn't screw up, your math is correct. All depends how you look at things. My calculation was based on 3.2" to the foot (26.67%) , whereas you are going from track gauge 15" to 56.5"( 26.55%). Using 26.55% would make things 3.186" to the foot.
No matter how you look at it 3" to the foot would be the easiest, anything else is going to have a lot of decimal places that need to be rounded off.

Nyle

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FLSTEAM
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Re: 15" new build question

Post by FLSTEAM » Fri Nov 11, 2016 7:46 pm

As far as where to run it? I'll work that out when I'm done building. I think I'll have plenty of time to address that issue.

Nyle
I first built my Mogul to 3" scale using track standard in LS posted by Sandy Whittum. My engine ran fine on his railroad, the RSME railroad and the Bluebird & Western in Ohio. But...when I took it to John Woods 5" scale RR I was unable to run without picking the frogs. I looked into changing my wheel profile to 5" but that presented 2 problems. First there was not enough clearance between the proposed wheels and the frame. Second, I would be unable to run on the old tracks. So...I compromised and changed to a 4" scale profile.
I could run on both scale tracks. Word to the wise, you better know where you are planning to run. Not all 15" ga. tracks are the same. Just to make it simple east of the Mississippi is 3" and west is 5".

John B.
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Re: 15" new build question

Post by Rob Gardner » Thu Nov 24, 2016 12:53 pm

Nyle, how large a lathe do you have access to? You will likely need a 20" swimg or more to turn drivers that large. A Berk's 69" drivers would be better than 17" in diameter. An 80" driver will be pushing 21" in 3.2" scale. Big stuff. I do know where there is a set of 3" scale NYC Hudson cylinder castings in 3" scale and a a couple other frame parts if you are interested.

Rob

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Re: 15" new build question

Post by JKreider » Thu Nov 24, 2016 2:38 pm

If you do decide to build a Berkshire and particularly an NKP Berkshire (Wow, an exciting project!), I have many original NKP detail drawings. I also have many original casting drawings including many from General Steel Casting for the NKP Berkshire parts. I have a list of all these.
Then there are the many model 1-1/2” scale drawings which I have created which are designed to create a bolt-up simulation of the NKP S-2 and S-3 class Berkshire cast locomotive bed. These could be doubled in size for a 3” scale locomotive.
Rich Killen of Plan Ahead Designs offers a very nice and complete set of 3D drawings based on my model parts, and for a very reasonable price I might add.
As Rob Gardner mentioned, there are 3” scale Hudson parts around and in fact, the patterns are still around. A Hudson cylinder block would be short on the stroke compared to a Berkshire, but its suitability would come out in an overall evaluation of the parts which would be part of your build process.
I have created a public Facebook group titled “Berkshire Modelers – 1/8 Scale 2-8-4” where the discussion is around prototype details and building of Berkshire models in the larger scales. Anyone interested is invited to join.
Jim Kreider

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