# G-gauge Model Mallard



## mallard (Jan 3, 2015)

Hi all, I'm thinking of making a model of Mallard for my nephew, along the lines of this:
http://www.mylargescale.com/Feature.../The-Milwaukee-Road-Hiawatha-F-7-project.aspx

I've found the same Aristocraft Pacific motor block to base it on, and I was wondering if I can use it with the Bachmann piston and drive rods from their 4-6-0? 
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_148&products_id=4803

My main concern is that the cylinders are a bit wide; as the aristo block includes a connecting rod, I was wondering if I could use theese pistons from the Bachmann 2-4-2 instead:
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_597&products_id=6112
These are a little less wide overall, and also have the advantage of having additional hooks, which makes them easier to mount.

However I gather Aristocraft and Bachmann are to different scales, will these items be incompatible?
If so, could you recommend another motor block/and or different piston set to use? As this is mostly a toy realism isn't the most important thing, I'd like to keep it as simple to build as possible, so pre-built pistons would be prefered.

For the body I was thinking of a 3D printed shell, probably mounted onto a simple wooden chassis; I read in another thread here that others have done it, but I don't have any experience with 3D printing. How durable is it? I've heard that it's not really suitable for toys/rough handling yet, and started considering making the body out of wood as in Rangerjoel's Hiawatha F-7 build log. I'm not very confident in my ability to do this though, and I was wondering if anyone could hazard a guess as to how much this might cost to have CNC routed?

I'm kind of new to all of this, so comments, suggestions and warnings all welcome.


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## vsmith (Jan 2, 2008)

The Aristo block and the Bmann rods are very different sizes. Your best bet is to trawl Ebay for a used Pacific, if the brick has already been worn out all the better you can swap yours into it. There is a chap on Large Scale Central , Mark Dashnel, who does custom 3D printing in G, he might be able to help the shell.


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## Pete Thornton (Jan 2, 2008)

> I've found the same Aristocraft Pacific motor block to base it on


That is probably a good base to start with. I once looked closely at the Aristo Pacific with the idea of making a gauge-1 (10mm:ft) scale LNER Peppercorn A1 Pacific. That would be very similar to Mallard (the LNER A4 'Streak' - right?).

The advice to find the rest of the Aristo frame is probably best, as then you'll have cylinders and rods that miss each other and work smoothly.


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## Jerry Barnes (Jan 2, 2008)

I've use the Pacifics for several builds, see my web page under projects. I use the whole Pacific base, that way you get the cylinders and frame. No reason to mix and match. I've had good luck with the older style and newer blocks. Easy to buy another for parts.

Good plans and pix here:
http://www.railalbum.co.uk/steam-locomotives/lner-a4-1.htm


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## ralphbrades (Jan 3, 2008)

I don't know where you are in the world so I will be fairly non specific... When I investigated the prospect of 3D printing for the ends of my Peak locos the cost was in the thousands of pounds sterling range. The same would be for CNC routing. It is not the cost of the work -but rather the design work that has to go into the production of the machining file.

All of the "A4" type locos that I know of in the larger scales are carved from wood. It looks a complex shape but you have to remember that these things were made using a roller with a planishing hammer and sandbag. Looking at it in perspective there is shovel nose at the front with the wide arch of the Wooten firebox carried lengthways. There was a wooden A4 in the previous edition of the Gauge '3' Society newsletter that was carved from wood and it was live steam and gas fired as well.

The nearest match to LNER Garter Blue is Ford Fjord Blue.

regards

ralph


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## mallard (Jan 3, 2015)

Hi guys, thanks for all the replies.
Having done a bit more searching, I'm coming to the conclusion that I might be better off using a Bachmann 4-6-0 chassis
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_148&products_id=4086

This seems to have several advantages over the Artisto Pacific block:
- It's readily available from their parts department and relatively inexpensive compared to the Pacifics I found on ebay
- The middle driver doesn't have flanges - I assume this is in order to allow it to navigate smaller radius curves. As my nephew only has small radius curved sections at the minute, this is actually quite important.

It does also have a couple of disadvantages:
- The Aristo block powers all the drivers, this only powers the last set so seems likely to have less omph. I did think that maybe this could be mitigated by also powering the tender if need be, although I imagine getting the gearing right might be a bit tricky.
- The Bachmann block is designed for a 4-6-0 and there isn't room for a trailing bogie truck as is, so it'd require careful modification. Having looked at the parts diagram on the Bachmann website, this seems a plausible option, though not necessarily an easy one.
- The drivers on the Aristo block look more the part, the ones on the Bachmann block look like they might be a bit undersized. The front bogies also look a bit far apart.

On balance, I think the pros outweigh the cons.



> There is a chap on Large Scale Central , Mark Dashnel, who does custom 3D printing in G, he might be able to help the shell.


Thanks, I saw his page on Facebook, I'll try and get in touch with him to have a chat.



> the LNER A4 'Streak' - right?


Yes thats the one, it's the record holder for fastest steam engine.



> I've use the Pacifics for several builds, see my web page under projects.


Thanks, I actually bumped into your page already in the course of research, you have some nice builds. I wish it snowed enough here to justify building a snow blower, because those seem like a lot of fun to build and operate!



> Good plans and pix here:
> http://www.railalbum.co.uk/steam-loc.../lner-a4-1.htm


Thanks again, I have quite a good book on Gresley locomotives with the same side-view plan, but I'm having trouble locating a good diagram of the front and rear views; could anyone point me in the right direction?



> Easy to buy another for parts.


I looked on ebay (albeit only for a couple of days so far) but have only found full/boxed Pacifics, for ~£450. Any idea where else I could look? I've succeeded in finding the motor block, but the chassis is proving more elusive.



> I don't know where you are in the world so I will be fairly non specific...


Ah yes sorry, South East England.



> It is not the cost of the work -but rather the design work that has to go into the production of the machining file.


I came across a 3D model of the engine and tender already, although these do need some modification - I spoke to a couple of 3D computer graphic artists who estimated £100-£200 for the changes - although I can see how that could inflate rapidly. You can have 3D models coloured during the print process now apparently, but it's quite expensive and I still have reservations about how durable the prints are. My main reservation about a wooden body now is the ability of the Bachmann block to move it.



> The nearest match to LNER Garter Blue is Ford Fjord Blue.


Good to know, thanks.


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## Pete Thornton (Jan 2, 2008)

> this only powers the last set so seems likely to have less omph.


It doesn't actually have anything to do with the 'oomph'. If you look at a typical steam engine, the connecting rods on one side are 90 degrees from the ones on the other side. Thus the drive is carried from the driven wheel to all the other wheels by the rods.

Aristo added multiple gearboxes - unusual in a steam engine model - so the rods became irrelevant and could be sloppily fixed to the wheels. They also let the axles pivot so the loco can navigate rough track - which the Bachmann doesn't do quite as well.



> the ones on the Bachmann block look like they might be a bit undersized. The front bogies also look a bit far apart.


Yes, they are much undersized - but if you make a 1/36th scale model, they might be right ! They are too far apart also - an LNER 4-6-2 has drivers that almost touch, to minimize the wheelbase.

The front truck is a source of problems and has to be loosened up or weighted (google it.) It is too long, as Bachmann wanted the loco to go round R1 (2' radius) curves. Nothing to stop you shortening it. 

The trailing truck isn't much of an issue (apart from getting your hands on one.) The B'mann 4-6-0 is just plastic (we also call it the 'ten-wheeler' or, for some special versions, the 'annie' as in 'anniversary edition'. The latter has metal rods and other improvements.)



> I came across a 3D model of the engine and tender already, although these do need some modification - I spoke to a couple of 3D computer graphic artists who estimated £100-£200 for the changes


Mallard is a big, complicated locomotive. You could persuade your son he needs an "Emily", which is a decent representation of a Stirling Single (and parts kits are available to make it even better.) Or wait until B'mann comes out with a Large Scale "Spencer" model in the Thomas series !


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## East Broad Top (Dec 29, 2007)

The Bachmann chassis does not lend itself to being kitbashed very easily. I've got one here that I'm turning into a 2-6-2, and it's been a mess. I've had to add a bunch of reinforcement and extra bits to compensate for what I cut off of it. Quite frankly, I would have been better served just designing a new chassis and cutting it. (Pete, this isn't #11, though that's now on the drawing board.)

For the Mallard, I'd definitely go with the Aristo as a starting point. It's going to be pricier, but I've long-since learned that it's often better to spend the time/money/energy to use the right bits and pieces. Otherwise, you'll always be looking sideways at it, thinking "gee, I should have..." 

Later,

K


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## Scott (Jan 29, 2008)

Be prepared for some time and some setbacks. If you break the model into sub-assemblies it will make the build easier. Look at what is easiest made and then progressively work up to the more technical items.

Fiverr is a website where for a small fee you can use the services of a professional to quickly model / convert what you need. I've looked at it to convert some plans that are too difficult for me to assist with my building needs.

Play around with some 3d modelling programs to get the feel for it - Also check out Shapeways.


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## Jerry Barnes (Jan 2, 2008)

All the Aristo's I bashed were used ones, so not so pricey. Also, with the Pacific everything is in the right place, no need to move parts around and re-inforce. Check out the US ebay and you'll find what you want.


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## mallard (Jan 3, 2015)

Ok, thanks for clearing things up with regards to the gearboxes.



> They also let the axles pivot so the loco can navigate rough track - which the Bachmann doesn't do quite as well.


What do you mean by rough track exactly?



> Yes, they are much undersized - but if you make a 1/36th scale model, they might be right !


Yes I'm actually quite torn with regards to what scale to go for. I had wanted to go for 1:24 (because he currently has the old PlayMobil Wild West train which is at that scale) but that'd make the engine alone ~54cm long and the wheels would look tiny. So I'm thinking either 1:32 all over (engine length = ~40cm) or 1:32 for the length and 1:28 for the width and height.

With regards to the trailing truck, Bachmann make a front truck that looks like it could do the job:
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_597&products_id=6114
They also make a rear truck, but this one seems like it might be harder to make work with a modified chassis (the frame might restrict how much it can turn)
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_597&products_id=6113



> Mallard is a big, complicated locomotive. You could persuade your son he needs an "Emily", which is a decent representation of a Stirling Single


Hah well it's for my nephew, but in time either it'll pass to my son or I'll be good enough at this to make my son a 'proper' one. So this is more of a practise run/learning exercise. Realism/detail isn't too important, my father is the only one who would notice it's not prototypically accurate, and I'm pretty sure he'd be chuffed enough that I made it to overlook any cosmetic inaccuracies. 



> Or wait until B'mann comes out with a Large Scale "Spencer" model in the Thomas series !


Any idea when that might be? I had been looking at the thomas range as a starting point as it happens.


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## mallard (Jan 3, 2015)

> The Bachmann chassis does not lend itself to being kitbashed very easily.


hm ok good to know, having looked at the service manual on the Bachmann website it does seem possible, but not particularly easy.



> For the Mallard, I'd definitely go with the Aristo as a starting point.


It does seem like the better block, although the flangless wheel on the Bachmann block gives me the impression that it goes round tighter curves (I think they only have R1 track at the moment). Would the Aristo be able to handle these?



> Be prepared for some time and some setbacks. If you break the model into sub-assemblies it will make the build easier.


Heh yea thanks, I am very much still in the 'thinking about' phase than the 'definitely committed' one (measuring twice before I decide to cut!). I would prefer to keep it as simple as possible, so a prebuilt chassis would take care of one sub-assembly at least; there don't seem to be a whole lot of 4-6-x chassis to choose from in large scale though. Are there any alternatives to the Bachmann or the Artisto Pacific that I've overlooked?



> Fiverr is a website where for a small fee you can use the services of a professional to quickly model / convert what you need. Play around with some 3d modelling programs to get the feel for it - Also check out Shapeways.


Yea I've heard of Fiverr, one of my friends has spoken highly of it too. I am also 'familiar' with Blender for 3D modelling, but I've not used it in some years and I'd rather shell out a bit to have it done right than to do it all myself and not realise something is wrong with it until it's been printed. Shapeways is actually where I found one of the models; it's N scale (1:450) but quite high poly so it ought to scale up well.



> Check out the US ebay and you'll find what you want.


Thanks, I'll set up some searches/notification alerts for that.


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## Pete Thornton (Jan 2, 2008)

> What do you mean by rough track exactly?


Many of us are running in the garden, where things get a bit bumpy (like the real thing) as trees grow roots, ballast shifts, etc.

All track is rough at the microscopic level, so only 3 of the Bachmann's 4 wheels will be touching at any one time. The manufacturers cope by making the flanges large, so when a part of the track dips the wheels don't derail. Check out "The principles of model locomotive suspension" from the Scalefour Soc over your side of the pond. http://www.clag.org.uk/41-0rev.html

In practice, you'll hardly notice unless you try to pull 3 coaches round R1 curves with the Bachmann 4-6-0. On tight curves there is binding and much resistance, so the 4-6-0 will struggle.



> They also make a rear truck, but this one seems like it might be harder to make work with a modified chassis (the frame might restrict how much it can turn)


The LNER pacifics had outside-frame rear trucks, like that one. Can't see the problem making it fit - just cut more plastic away!



> with a Large Scale "Spencer" model in the Thomas series !
> 
> Any idea when that might be?


Your guess is a good as mine, but I'm not holding my breath.



> the Bachmann block gives me the impression that it goes round tighter curves (I think they only have R1 track at the moment). Would the Aristo be able to handle these?


I don't know. I have one, but I never tried it on R1 curves. There is plenty of play in the center axle. I doubt it would look very good - in fact, I can't see ANY Mallard model looking good on 2' radius curves. A 1/32nd scale A4 is about 30" long !

If you'd rather just spend money, Aster made some electric A4 models many years ago. They seem to sell around $5-10K.


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