A bit long, but logical...

Dear Ken,

In all, I suspect it'll be a bit long as measured against "typical" colonial tenders, but a walk thru http://www.australiansteam.com/ should give many examples of tender design to contemplate...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

PS with the improved DCC mech under the B'mann 70 and 44 tonners, maybe they might provide another cost-effective tender-powering option, with more-appropriate "tender truck spacing"?

Other options

I suspect you are right, Prof.  I was just playing with this one first because I can find the specs easily and I know I can get the model (Athearn, P2K, and others) pretty easily and cheaply.  Now I have something to start from, and I know that I need to look at something shorter.

Nice Tender

That would look good behind a 2-8-0, 2-8-2, 2-10-0 or perhaps a 2-4-4-2, 2-6-6-0 or 2-6-6-2. That tender is a prototype. The question is "is it plausible"? I say yes it is.

Could this be the unit that powers the whole engine? (Tender Drive)

Bernd

"like something you might see in South America?"

Are you freelancing the British in South America? The rivet counters will tell you Spanish or Portuguese would be more prototypical....DaveB 

Tender drive

That's the idea.  I don't even have a specific locomotive in mind yet.  I was just thinking about using an HO diesel mechanism to power a locomotive.  After further thought, I remembered that I have an Atlas S-1 which is very close to the mechanism I drew - the only difference is that the truck spacing is 1.5mm longer than what I drew.

I am certainly open to suggestions on how to improve the look of the tender - make the tank longer, wider, taller, etc.  I think the only way to justify such a large tender is if the hypothetical railroad has an especially long run between water and/or fuel stops.  The tender is certainly long, especially for a British locomotive, but it looks (somewhat) plausible to me for a railroad across a reasonably large country.

Sort of, maybe, and who knows?  I've seen some South American railroads with a very British feeling to the rolling stock.  In fact, one of the books I have has a chapter on an Indian locomotive, and it shows a copy built for an Argentine railroad.  I'm not thinking of something specifically South American, but that does have the mix of British and American influences that I think the tender as drawn most resembles.

A tender idea

Ken,

Make it  taller. About equal with the imaginary engines cab roof line.

Bernd

Its been done

Both N and HO modelers have put RSC2 drive trains under 6 axle tenders.  By the way, you can also take the Athearn wheelsets and reguage the wheels to run on a different/more accurate gauge.  I took an Athearn HO engine and modified the wheels to run on HOn3 track.  May have to narrow the gear connector  to allow the wheels to come in.  You could also proabably substitue larger diameter wheels from a more modern engine and get wheels that are 42" diameter rather than 40 or so.

The danger of having parts on hand

The only practical reason to use a tender drive is if I have a steam loco mechanism with no motor.  I don't, so it's all a moot point..

Oh, wait.  I have an old Tyco 2-8-0 which had a tender drive, and I don't have any need for it at the moment.  You know, a large tender would make better sense behind a large locomotive. How about a narrow gauge 4-8-4?

I can even use the same sideframes for the lead truck as I'm using for the tender.  That's a case for learning resin casting.

Meter gauge?

As long as you are headed down the rabbit hole why not jump in with both feet. Quite a bit of narrow gauge in the world is/was meter gage which is represented in HO scale by HOm 12mm instead of 9mm spacing from N-gage track. Also known as TT gage track. 

Matt

"Colonial" railways, 3' 6" gauge...

Dear Matt/Rust, Ken,

Naah, if Ken really wanted to get "Colonial" he'd be doing it in 42" gauge, using 1/4" bodies on S-gauge track...

http://www.qldrailheritage.com/org/rfox.htm

http://www.oaustkits.com.au/clf.html

http://www.oaustkits.com.au/catalog/product_info.php?products_id=124

http://www.oaustkits.com.au/catalog/product_info.php?products_id=121

http://www.oaustkits.com.au/catalog/index.php?cPath=26

Happy Modelling,
Aim to Improve,
Prof Klyzlr

doing it in 42" gauge, using 1/4" bodies on S-gauge track

or on HO track using 1:64 scale to get more railroad in the same space. I hear it's actually pretty popular in New Zealand or somewhere down under? .........DaveB

When "standard gauge" = 42" ...

Dear Dave,

Yep, New Zealand is filled with 42" gauge prototype, so modelling 42" gauge is a "gimme".
(Saying "standard gauge" in NZ is likely to make even non-RR people think 42" gauge) 

Result? Possibly the highest percentage of Sn42 modelling per modeller head anywhere...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Portuguese or spanish

Not really. The first Brazilian railway used british locomotives, and the first successful one was projected, funded, built and operated by British citizens (and named, acordingly, São Paulo Railway Company, ltd). Other companies used a mix of British, German and American with a few others bulders' locomotives during steam era. Diesel and late steam is mostly made in USA, with Baldwin dominating steam and GE the diesel fleet.

It is worth considering that by the time railroads started in Brazil and others LA countries were independent from its former colonial powers and seeking new trade partners.

I thought about Sn42

I suppose that, to some degree, 55n3 and Sn42 are pretty close to the same thing.  At least, a model might look right on either one.  With that said, I have my reasons for liking 3' gauge, and I feel like freelancing a bit, so why not?  As long as it is at least plausible, it satisfies me.

I think I was drawing something too old.  It needed to be newer and bigger to fit the long wheelbase.  So, I've been updating it.  This is what I do when I'm bored in the middle of the night in a hotel room.

Starting to take shape

Ken,

It's starting to look pretty good, very plausible. I really like the cab/tender area. Makes it look a bit streamlined. I think you've got something buildable here.

Bernd

I'm having fun

Thanks, Bernd.  I've seen photos of an Indian locomotive with a matching cab on the tender, and I liked the look, so I decided to incorporate it here.  Before all is said and done, I think she might end up as a 2-8-2 instead of a 4-8-4, as those small (35") drivers just don't make sense with high speed features like 4-wheel trucks.

Also, in case anybody is wondering why I'm bothering with this instead of something more "useful" or at least more in line with my primary interests, there is method to my madness.  For one thing, I enjoy this form of armchair modeling, and that's really the only requirement, right?  More practically, however, I am teaching myself new skills with Sketchup every time I do something like this, and some of those have already come in handy for some of my D&W projects.  I get to practice on something unimportant and have fun doing it. 

Having Fun

You have improved with your drawings. So it's working. 

Actually Ken perhaps a 2-8-4. The 4 wheel truck is used to hold up a larger fire box. Shorten up the front porch a bit to. So in the next picture you draw lets see a 2-8-4.

Bernd

Also, in case anybody is

Ken, are you still with us?

Did you go any further with this powered tender idea?

Where in the World is Ken

Ken hasn't been on since around 2013. At the time I was working with him on the tender drives. I've got one of his experiments with Shapeway parts. Did not work very well. 

It's strange that he just disappeared from the face of the earth like that. Do remember him being an engineer for CSX or NS. Makes one wonder what happened to the person. I tried contacting him through his private e-mail but no answer. 

Bernd

Found the post.

Like I said Ken and I worked adding a tender drive to steam engines. Here's the link.

https://forum.mrhmag.com/post/whats-on-your-workbench-12196260

Bernd

Last contact we had with Ken