Large Scale Central

Union Pacific SD40N - Teaser

You are going to be waiting a LONG time. And I am also in that 3 week window between 0 and 100 degrees.

Good to know I’m not the only one that takes on multi year projects…

Chris, I’m very patient. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)

Craig, I started my Dash 9 with Canadian cab in 2012, and it’s still not complete. You’re definitely not alone.

Shane

I have the underside of the sill / frame stripped of the bits I plan to replace. Gone are the old frame rails, air tank mounts, jack pads and builder plate spots. Waiting for some new chisel blades for the Xacto to arrive so I can get the remaining bits against the steps. Then it will be some final sanding and I can move to pilot modifications.

Thanks,

Chirs

Before photos:

After photos:

Pilots have been stripped clean. All holes were filled with stretched sprue and the big hole filled with .080" styrene. I need to add backing strips to the back for that joint, then bondo and final sand them. I also cut the tabs off that were supposed to represent the end of the lower step. The proto I’m building did not have the upper corners trimmed, so they will remain square.

I ran a low res prototype of my 3D tank to see how it was going to work out. I have decided to make a few changes for the final version. First some comparison photos.

First up is an end shot comparison. My tank matches dimensions for the actual tank, so you see that it comes back in on the top instead of just being vertical like the original. My mounts are also narrow vs. the original as I am moving the frame rails inward closer to where they should be. Large holes on the upper edge are for locating the 3D printed tank mounts.

Underside shot shows the prototypical design of the tank. The proto is not actually round, but broke every 10 degrees in a series of short flats that eventually form a round shape. I did this on the proto tank but it is very subtle. After I finish sand the tank smooth, that detail will vanish, so I will just change them to be round.

The original tank is not as wide as it should be.

The new tank at the correct width.

So after the proto tank was made, I decided to make a few changes. I am going to remove the speaker provisions and the mount pad for the Phoenix board and relocate them into the body shell. I decided to do this because I can’t seal the tank up.

I’m going to remove the end sheets from the print and replace them with laser pieces. This will make sanding the profile much easier to do. The end sheets are what you see sticking up above the curve section.

I’m also going to remove the top sheet and replace it with a piece of .015 styrene. The vent block behind the sight glass will also not be on the print. This also is to make final sanding easier. The mounts will remain part of the printed tank.

Looks good Chris. You’ve almost caught up. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-tongue-out.gif)

Shane

PS - Have you noticed that SD40-2’s are no longer shown on USA Trains website?

Hahahaha…almost caught up…you are a funny guy. (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-tongue-out.gif)

I had not noticed they were no longer on the USAT website. If you flip thru their 2017/2018 catalog the SD40-2 is not there either.

Curious. I would have thought that would have been a decent seller for them.

I seem to remember someone at the convention saying they talked to Charles Ro and was told probably next year they will make another run of them… I think. But it sounds good ! Lol. With the state of things so in flux I guess they don’t want to put a ton out on a soft market.

I guess my mindset is still kind of stuck in the HO market, where (nearly) every manufacturer makes an EMD F unit, and they all seam to find a market for them. I keep forgetting that I am in a niche hobby, and that I work in a niche industry…I guess I am just a niche person and I don’t even know it.

Sometimes you are a niche person, sometimes you aren’t very niche…(http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-sealed.gif) Maybe we will get super lucky and they will retool a new improved model!

If your dealers have limited space, do you want it held by a product most had a chance to acquire already, or the new hot gotta have?

Cool project. I like the prototypical shape of the new fuel tank.

John Caughey said:

If your dealers have limited space, do you want it held by a product most had a chance to acquire already, or the new hot gotta have?

True. What is the new gotta have?

David Maynard said:

John Caughey said:

If your dealers have limited space, do you want it held by a product most had a chance to acquire already, or the new hot gotta have?

True. What is the new gotta have?

M Class 4-8-0?

I’d love to have a Mastodon!

edit; apologies for thread drift…

John Caughey said:

edit; apologies for thread drift…

No apologies required (it was Shane’s fault anyway) It is curious why that loco disappeared from the offering. I personally would like to see the 1:20.3 market return. But any new product is a good thing.

This is the pilot with the lower corners corrected, and the lower doubler plate added.

Completed frame in a more prototypical location. The real loco is not flanges on the bottom, but a full plate. For operational purposes I chose just to model the outer edge.

I 3D printed the outer section of the bolsters. I also printed the jack pads, but made them to short so I will be making new ones.

I am now working on new mounts for the trucks. I’m going to try and make them so I can negotiate a 4’ R without having to cut clearance holes in the frame rails.

I have a pretty solid idea on how I’m going to mount the trucks with the new frame rail spacing. I’m going to rework the truck mount a little, reducing it’s width down closer to the motor block width. I will be dropping where it widens to mount the side frames to below the level of the frame. I am going to remove the forward side frame spacer and integrate that into the main mount. This will allow the truck to swivel in excess of 15 degrees (shown in picture) allowing it to negotiate a 4’ R curve should I run into one.

Still have plenty of detail and final design work to do on this mount and the side frames before i make the parts. I feel confident enough to move forward with the frame detail knowing I won’t have to cut a hole in it. Next up is the traction cables.

I like the bolster and jack pad details. I want them for my GP30 build… Your making me want to restart that project. And the fuel tank rebuild is nice as well.