Santa Fe 4-4-2 (Atlantic)

[kiwi_al]

This arrived with the Madame Queen shell from Adam (draskoasshat). It has a lot of fine detail is is very accurate, it's modelled on #1491. The challenge is to find a mechanism for it, the Bachmann K4 4-6-2 has the correct size drivers but the Bachmann is quite pricey. I have a set of K4 drivers so I will probably make a custom mechanism for it. So this is the start of building ATSF 1491. The cool thing with this shell is that the number boards have 1491 printed on them and they are designed to light up

Proto Photo:
http://m.rrpicturearchives.net/showPicture.aspx?id=4975837

The headlamp became detached during transit to NZ, fortunately it left a couple of nubs where it should go. I will glue the headlamp back when it's almost finished to lessen the risk of it coming off. You will see some remnants of the raft along the lower edges of the shell, I've yet to clean them off properly.

3D Printed Shell:

[Cajonpassfan]

This I got to see, one of my favorites!
As to the mechanism, you may be better off starting with a light Pacific (BLI, MP, Atlas?). The 1480 class as rebuilt, including the 1491, only had 73" (or 74") drivers, with only 6-10" spacing between them. The prototype K4 had 80" drivers with although I don't have a model of it I suspect it's too big for this little pup.
Best of luck with this build, I'll be following with much interest.
Otto,

[kiwi_al]

This I got to see, one of my favorites!
As to the mechanism, you may be better off starting with a light Pacific (BLI, MP, Atlas?). The 1480 class as rebuilt, including the 1491, only had 73" (or 74") drivers, with only 6-10" spacing between them. The prototype K4 had 80" drivers with although I don't have a model of it I suspect it's too big for this little pup.
Best of luck with this build, I'll be following with much interest.

Otto,

Thanks Otto,
The reason I was thinking the K4 is that the drivers that Bachmann make are pretty much the correct size at 72.5669 inches close to 73". I have also found I can get a K4 streamlined mechanism for a good price so I am seriously considering that. Since I already have K4 drivers I'll do a styrene mockup of a mechanism and see how it looks then post that here and get feedback. At the end of the day it needs to look right and I'm happy to change course to get it right.

Alister

[Cajonpassfan]

Undersize drivers seem to be the norm, but I didn't realize just how undersize the Bman drivers are. The good news is that with a two-coupled loco, you don't have to cheat as much, they are perfect!
Attaching another pic of this beauty for your use. Kalmbach published plans for the loco some time ago. Do you have access to them?
Best of luck!
Otto

[kiwi_al]

Undersize drivers seem to be the norm, but I didn't realize just how undersize the Bman drivers are. The good news is that with a two-coupled loco, you don't have to cheat as much, they are perfect!
Attaching another pic of this beauty for your use. Kalmbach published plans for the loco some time ago. Do you have access to them?
Best of luck!
Otto

Hi Otto,
When I read your post I didn't think I had the Kalbach drawing but I do, I turned the page in my copy of Steam Locomotives of the Santa Fe (a former shopmans scrapbook) by Frank M Ellington and there it was #1491! A big thank you !! Now I going to have to go through all my steamers and measure the rear trucks for a 47 inch one!

[dnhouston]

Following with extreme interest.  I have always loved the Santa Fe Atlantic and Prairie engines.

[kiwi_al]

Here's a little update, cleaned up the artifacts at the bottom of the shell a bit and running boards and slid some drivers under it. The shell is just placed in top of the drivers.

[kiwi_al]

The Bachmann parts arrived today, that was fast!!
I need to thin the whole mechanism by about 1 - 1.5mm each side before I shorten it, then I'll shorten the mechanism and test fit the shell.
Add all the parts and hopefully have a running 4-4-2. The mechanism is a Bachmann K4 4-6-2 streamlined, they don't have the non streamlined mechanism available so I'll mill this down a bit.

[kiwi_al]

I've thinned the mechanism somewhat and cut it up.I need to thin it a bit more from the black lines down to the bottom.

[kiwi_al]

Trimmed more off the K4 mechanism and test fit, need to trim off the tender post.

[kiwi_al]

it turns out that I can't make the Bachmann K4 mechanism work and use the Bachmann motor and have the drivetrain intact. I have decided to make a custom brass split frame mechanism so that I can use the Bachmann motor, gears etc.

I have now had some spare time, so I've mocked up some styrene and added some cut outs for the drivers. I'm using 1.5mm styrene sheet for strength.
I haven't as yet boxed it in it's just two bits of styrene with drivers fitted so I can get a sense of where things should fit. I will move to brass when I've got the wheels fitting correctly and the front and trailing trucks in the correct position. This will take a bit of time. The shell is sitting too low the cow catcher is hitting the deck!!

[Lemosteam]

it turns out that I can't make the Bachmann K4 mechanism work and use the Bachmann motor and have the drivetrain intact. …

@kiwi_al , Please elaborate as to why. I have been mulling this for a long time and am very curious about your findings.

[kiwi_al]

So the designer who happens to be Adam (draskouasshat) and it was not designed with a mechanism in mind, it's an accurate representation of 4-4-2 #1491. I saw that a good starting point might be the PRR K4 mechanism as it had the correct 73 inch drivers. However when I got the mechanism from Bachmann I noticed it was quite tall and a bit fat. I thinned it down then cut it then the trial fitting began. The problem is the motor sits near the top of the mechanism and you can't take too much off before exposing the motor so going the custom route enables me to save the mechanism for another project instead of going too far and ruining it.
You are a PRR modeller and the PRR locos seem to be a bit beefier than the ATSF ones- it may well be that you can use this for your application. I went the cheap way and bought a complete mechanism for about $50.00 USD instead of over $200.00 for a DCC/ Sound version. That's the decision criteria I used anyway for good or bad. I'll post another picture a bit later showing the difference between the styrene mockup (which does need altering) and the metal mechanism I chopped.

[Lemosteam]

Thanks, I was worried it might be a little more serious than that, like there was no way to shorten the mech to remove drivers and still have gearing, and valve linkage, etc.

[kiwi_al]

I deliberately kept the driver spacing standard Bachmann, for the ATSF 4-4-2 it's only about an nscale foot out so I'm happy with that. I can use the siderods mainly and everything should work the same or similar. Shortening the mech is straight forward, it also has a nice motor which is another reason I didn't want to hack the top too far (I did strip the mech down before thinning and chopping ) . The one thing I'm not sure of is how to get a rear truck to fit 47" wheels!!