Pt. 1 --- N Scale DD35A & B Build

This page will be about researching building a DD35A from an Atlas GP35 shell and a DD35B Shell from James Trains. The chassis will probably be either a powered Bachmann DDA40X Generation 2 chassis or the later DCC chassis. They are different and I'll touch on that further down the page.

To get a feel for what needs to take place I used the first three images (below) by Jean-Denis Bachand from thedieselshop.us. The site is a great resource for diesel information. Link to it ( HERE ) and a link to the DD35A & B info ( HERE ).



I tried to get both images scaled exactly the same in the same image. Got close but above the A unit is pretty close and the B is a little large. I scaled off the truck wheelbase as it was a know (or was suppose to be).



Above the B unit is scaled a little closer to what it should be and the A is a little smaller in the image than it should be.



Above is hopefully the sequence of events that will happen. Let's keep in mind I've never done something like this before so close might have to be close-enough.



Above are two DB35B's made from James Trains kits.



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Time to move on to cutting things up and designing parts.......

You can follow this build on my site also ( HERE ).

Sumner

 

What a great start Sumner! This is going to be fun to follow.

 

Pt. 2 --- N Scale DD35A & B Build...

Time to plunge into this and hopefully not end up with two ruined shells (James Trains DD35B shell and an Atlas GP35 shell). I'm looking for another UP or SP GP35 shell to replace the one that I took off the Atlas GP35 chassis.



The goal is to cut out the flat radiator section in the DD35B and replace the area with a Fusion 360 designed flared radiator section like in the next image along with cutting off one end of the shell and grafting a GP35 cab on from an N scale Atlas GP35. Some worry here as I've never tried to design any part of a loco shell before.



I'll try and design the new section using some photos off the internet. It for sure won't be accurate down to the inch but hopefully will be OK for my tolerance of what is acceptable.



I did buy two of these shells with the hopes of one being a powered DD35A (this build) and the second being most likely an unpowered DD35B. I also bought a chassis from James Trains that the shell can sit on if you want an unpowered unit. It uses Fox Valley wheels/axles in James Trains truck frames.



Not sure exactly what these shells are printed from but they are not real brittle. I felt for sure that cutting close to the middle doorway would result in it breaking but it hasn't so far.



Took a few minutes to make the vertical cuts with the saw and even less time to make the long horizontal cuts with the Dremel.



I saw BadLand (on Trainboard and nScale) using one of the 8220 Dremels on one of his videos and decided to buy one. Took me awhile to decide as it wasn't cheap. I love it and it is now my go-to Dremel and my old one and shaft driven one pretty much sit now.



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Designed and printed some 4 ft. fan grills for the top of the loco as the new section there for the DD35A has the grills in a different order by size between the 3 foot and 4 foot grills. Hopefully I can paint these with out clogging up the grill. I'll do a test run. Moving past the point of no-return. I won't cut the end off where the cab will join until I replace the middle section with the flared one. It I cut it off now things might get a little flimsy.

You can find the print files for the 4 foot fan grills on my thingiverse.com account ( HERE ).

If you came into the build here you can go to the start of the build ( HERE ).

…. to be continued...

Sumner

 

Pt. 3 --- N Scale DD35A & B Build...

NOTE: This is not an accurate build of a DD35A. I've tried to 'get close' but at almost 80 don't want to spend a ton of time on this. I need to get back to laying track, adding scenery and finally running a train or two.

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Studied some pictures and some other models of DD35A's and ….



…. took some liberties in …...



….. designing a flared radiator section for the DD35A. A lot of the models that I looked at seemed to have done the same as a number of them don't look exactly like the pictures of the real thing (mine won't either). I'll make it (hopefully) run it a couple times and probably move onto another project.



The two images above and the next one are screen shots from Fusion 360.



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I took the print file into Chitubox and sliced it and printed it with the AnyCubic Photon M3 I bought for $209.



The print came out with what I think they call 'bloom' on the bottom (bloated and irregular surface). You can see it above and also the fan grills were partially clogged with cured resin even though I cleaned it a lot. Looks like the resin cured during the print. This didn't happen when I printed the grills before where they were open on the bottom. Here the grill is open for about .050” but then the print is closed below that. The flared radiators fared better but below them I didn't get a nice straight flat edge.

I'm going to open up the print (hollow it out) and add a skirt to the bottom of the print on the long horizontal edges and see if that clears up both the problems. If that takes care of those problems the rest I'm happy with.





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Keep in mind that this is N scale and these images if viewed on a computer are larger than the real thing.

If you came into the build here you can go to the start of the build ( HERE ).

…. to be continued...

Sumner

 

Thanks for the input guys. I kind of did what you covered earlier today I think. I hollowed out the shell where it is open under the fan grills...



... and that seems to be fixed but they are still really fragile.



I also put a skirt around the bottom of the shell and will see tomorrow how hard it is to remove. I kind of rushed it and think I might try to modify it if it isn't easy to separate. I only need one though so if I get one good one out of the two I printed I might call it good. I'll probably put links to these files up if there is anyone that might be interested in doing this at some point.

Sumner

 

Pt. 4 --- N Scale DD35A & B Build....

NOTE: This is not an accurate build of a DD35A. I've tried to 'get close' but at almost 80 don't want to spend a ton of time on this. I need to get back to laying track, adding scenery and finally running a train or two.

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I had a print that was good enough to use but wanted to work on a skirt around the bottom of the shell so I could still print with the shell horizontal and get a flatter bottom and better corners. The next two prints are the result of doing that along with …..



….. hollowing out the shell so that resin wasn't trapped in the top grills. If you look back to the last page ( HERE ) you can see that the grill isn't open everywhere do to excess resin that couldn't drain.



With the print hollowed out the grills are printing better but still have a couple broken rings. Of interest is that the rings and the spokes are the same width in the Fusion 360 design but the spokes print wider (both are .006”/.152mm). It amazes me that a $200 printer can print with this detail.



I worked on the skirt I had implemented some to make it break off from the shell easier and also beef up the grills a little by adding .002” to each of the round parts of the grill. To do that took me about another hour using Fusion 360. I'll put this file up on my thingiverse.com account so hopefully the changes help someone else if they follow this route.



The new skirt worked very well.



I had cured the previous set of prints for a total of about 5 minutes and they were really brittle so cut the total cure time to 3 minutes for these and that seemed to work better.



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I think I'll cut the two grills that are on the James Trains shell out and replace them with some of mine so that they all look the same. The ones on the shell aren't open either.



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I haven't painted a shell yet so this will be my first attempt . I'm going to try and mask off the grills and paint them by hand at the end as that seemed to work fine and I feel will be easier than trying to mask and paint them with a gun (open to suggestions on this approach).



So I finally got the nerve to glued the new print into the shell. Hope I don't have to remove it for any reason. I have two UP GP35's and was going to use the cab from one but since I was going to have to strip it decided why mess it up so started looking for a GP35 with any road name and strip and use it.

I did stay with the first two generations of Atlas GP35's as the cab (not the low hood also) pops off the shell and that will make the back cut on the cab not necessary and the joint there cleaner. Didn't know if the later Atlas GP35's were the same. I looked for a shell alone but the ones I found cost more than this complete loco. I'll keep my eyes open for a UP or SP shell alone and if I find one at a reasonable cost will buy it and use it with the chassis from this cab donor.

If you came into the build here you can go to the start of the build ( HERE ).

(NOTE: Keep in mind that this is N scale and these images if viewed on a computer can be larger than the real thing.)

Will continue this when I get the GP35 in my hands in a few days........

Sumner

 

Pt. 5 --- N Scale DDA35 & B Build...

NOTE: This is not an accurate build of a DDA35. I've tried to 'get close' but at almost 80 don't want to spend a ton of time on this. I need to get back to laying track, adding scenery and finally running a train or two.

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The start of some of the shell mods and also milling the frame for the ESU LokSound 5 Nano sound decoder and a 9 X 16mm speaker.



I cut off one end with a Dremel and then later worked it back to where it was square and flush for the GP35 cab to be glued on with a bench 1” belt sander and a file.



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I got this Bachmann DCC DDA40X for under $100 pre-COVID but they are selling for a lot more now. Don't want to screw it up but need to move on with the build.



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The speaker could go in the fuel tank area probably but getting it up at the top of the frame made wiring somewhat easier and I can add weight to the fuel tank area if there is room for more than what Bachmann put there already.



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With the frame milling hopefully done next up is modifying the shell some more as I felt that needed to also be done as you will see.

If you came into the build here you can go to the start of the build ( HERE ).

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(NOTE: Keep in mind that this is N scale and these images if viewed on a computer can be larger than the real thing.)

Sumner

 

Pt. 6 --- N Scale DDA35 & B Build...

NOTE: This is not an accurate build of a DDA35. I've tried to 'get close' but at almost 80 don't want to spend a ton of time on this. I need to get back to laying track, adding scenery and finally running a train or two.

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After making the flared radiator section and installing it the fact that the top of the shell didn't look like pictures of DDA35's and drawings of them started to bother me more and more. I had made the fans on the top as close to accurate as I could based on pictures and drawings but couldn't figure out why the distance between the lower fan/grill on the James Trains shell and the first one on the new flared radiator section were further apart that what it appeared they should be.



I started counting compartment doors on the images from the Jean-Denix Bachand drawings to the James Trains Shell. I found a section of the shell that didn't match the drawings and other photos, the section that I have red 'X's' in above. My guess is they were added so that a Bachmann DDA40X frame could be used to make a powered DDA35. The DDA40X frame can only be shortened so much in the middle before the two drive motors would come into contact. The DDA40X frame is needed to get the correct trucks for the DDA35.

Since I was going to be adding the GP35 cab to the front of the shell I decide to see if I could remove the 'red X' sections from the shell. This meant besides cutting the end off the shell for the cab I'd also be cutting two sections out between the fan grills. All of these would then have to line back up and be glued and hopefully not be too noticeable. I decide to take the risk and plotted out the cuts that would be needed.



Wasn't real sure how cutting sections of the shell out was going to go. One more chance to screw it up. It went well though and I feel the end results were worth it. Loco looks more prototypical now and it didn't take that long to do.



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I'm happy with how the shell glued back together. I'll know more when it is painted as that will highlight any problems there might be.



Patience with a file gets the top and side joints pretty close to each other on the DD35 shell and the cab. I cut the cab end of the GP35 shell off with the Dremel a little long and then worked the edge that needs to join to the DD35 shell with a file to get the vertical and top edges flat and square. It helped that I could remove the walkway and the cab section with the windows during this. They separate with this early shell (not sure if that is true with later Atlas GP35's).



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Next up will be shortening the DDA40X's frame to fit under the DDA35. I'll slide the GP35 cab on one end of the frame and the shell for the back of the DDA35 on the other end and measure the distance between them. That distance minus a little will be how much needs to be removed from the middle of the DDA40X frame.

If you came into the build here you can go to the start of the build ( HERE ).

(NOTE: Keep in mind that this is N scale and these images if viewed on a computer can be larger than the real thing.)

Sumner

 

Trying to get the shell parts ready for paint and this is my first attempt at stripping the paint off of a shell. The DD35 shell from James Trains came unpainted so no problem there. The GP35 Atlas shell was painted and I'm having trouble with it. Not sure how far to go and exactly what is going on.



Above is the cab part of the shell that I'm using and what I'm trying to strip. I took it apart as far as it would go and started soaking it in 99% IPA yesterday morning. Almost all the red shown above came off withing a couple hours using a firm new toothbrush. The remaining red came off a few hours later. The yellow at the bottom of the walkway and the yellow striping on the cab also came off fairly quickly.



24 hours later the yellow on the front of the hood isn't coming off and not much change since last night. The grey paint came off the side of the walkway walkway where the yellow was also. Under the grey on the walkway was the black which the IPA isn't touching along with the black on top of the roof.

So the question is will I get the black off and the yellow? I'm hopeful about the yellow on the front but not the black.



I'm paint with UP's colors and will use a grey primer over everything so maybe I've gone far enough or any ideas on how to remove more or even if that is possible? I don't want to get too aggressive and ruin the shell. I'd take a little loss of detail over that.

Thanks,

Sumner

 

That looks like one of the Kato-made Atlas GP35s. Whatever paint Kato uses for their base colors basically impregnates into the plastic, and there's no good way to fully chemically strip it without damaging the shell (don't ask me how I know this ). Luckily it's also really thin, so now that you've gotten the letters and stripes off you can paint over it without losing shell detail. A coat of gray primer should cover up the E-L colors.

 

Got an ESU LokSound 5 Nano in the DDA35 the other day. It only took about an hour with all the room there is using the N scale Bachmann DDA40X frame. Seemed faster than that after all the time I've put into this at this point. I'll put up a separate post on the install but put up a video today running the loco with the decoder installed and wanted to share that.

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For the video click the image above or ( HERE ).

Still have a long ways to go on this. Need to probably take a break and get more track down so I have someplace other than my test layout to run it.

Sumner

 

At this point I would never even finish the shell. I'd be too busy running the bare mechanism just to listen to that fantastic sound.

 

Pt. 7 --- N Scale DDA35 & B Build...

Getting close to installing a LokSound 5 Nano sound decoder. First though the frame needs to be shortened so that the GP35 cab can be glued to the DD35 shell and the frame ends up fitting the shell.



Above I'm measuring how much needs to be cut our of the center of the frame (not the area shown above).



I still had the frame in the mill from milling out the area for the speaker and decoder so decided to 'carefully' see if I could mill out the center section with the frame being held by not much in the vise. A cut was made through the frame on the right side (above) and everything held steady so I moved to the left cut.



The left cut also went fine. I made very shallow cuts on both sides but even shallower on this side as now the frame wasn't held in the vise by much of a surface and I didn't want the end mill to grab and screw things up. I also have the mill turned up to about at fast as it goes (over 2000 rpm – the mill has variable speed and I don't have to change belts/pulleys).



One the frame is shortened it becomes four frame pieces vs. two. Two pieces on each side. The pieces on each side need to be tied together for strength and to connect the track power pickup from the two trucks for each side. Also the two side frames need to be held together here as the screw that use to hold them together in the middle of the frame got cut out with the section of frame that was cut out.

I decided to use a piece of PCB (printed circuit board) to do this and did a quick sketch of what I wanted with some measurements (show above). I drilled 8 holes but only ended up using 4 of them. I also filed an electrical isolation gap down the middle (shown in next picture) as the two frame halves need to be isolated from each other because they pick up the track current from the two track rails.



A similar gap was filed into the bottom of the PCB. I like using PCB like this as it is easy and quick to work with and very cheap. This PCB, besides tying the 4 frame pieces together on the bottom also ties the two frame pieces on each side back together electrically. I drilled and tapped the frame for the 2-56 screws.



After putting the PCB in place and later with the one on the top I checked to make sure the two pieces on each side were connect (had continuity) but that the two frame halves weren't connected electrically (didn't have continuity).



Moving on to tying the frame pieces on the top something similar was done. Again PCB was used and taken advantage of. Two center sections were created and presented a place that the motor and decoder motor wires could be soldered to. They were separated from the frame halves by cuts across the PDB right in front of the four frame pieces. Now two of the pads on one end or the other of the PCB could be used to solder the decoder wires that are used for track pickup. This made installing the decoder very easy and fast as four of the main decoder wires that have to be connected could easily be soldered to this piece of PCB board and it also physically connected the four frame pieces together on the top.

The frame was again drilled and tapped for 2-56 screws but used 2-56 flat head screws here for more clearance for the wiring that was going to go in.



The motor wires from each motor were soldered to the PCB on each side and I added a wire from each side in the center to the two track pickup points on the PCB (blue and red wires above). This turned the loco into a DC loco with the DC current going from the trucks to the frame halves, then onto the center of the PCB board and then down to the two motors. Quick easy way to test the loco with DC on the test track. The shortened frame and motors all worked fine so time onto removing the blue/red wires and installing a decoder.



First though I wanted to glue the cab onto the rest of the shell and needed to strip as much paint as I could off of it before doing that.



After soaking for a little over 24 hours I got as much paint off as what is shown above. More soaking in the IPA wasn't getting any more off so moved on.

If you came into the build here you can go to the start of the build ( HERE ).

(NOTE: Keep in mind that this is N scale and these images if viewed on a computer can be larger than the real thing.)

Sumner

 

Pt. 8 --- N Scale DDA35 & B Build....

NOTE: This is not an accurate build of a DDA35. I've tried to 'get close' but at almost 80 don't want to spend a ton of time on this. I need to get back to laying track, adding scenery and finally running a train or two.
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With the Bachmann DCC DDA40X frame shortened .350” and …..





….. the resulting 4 frame pieces held together with pieces of printed circuit board (PCB) top and bottom it is time to install the ESU 58923 LokSound 5 nano DCC decoder in the DDA35.




I'm trying to get into the habit of testing the decoders before I install them with the decoder tester I built ( HERE ). I should do this when I get them in case they have to be sent in under warranty actually. I bought the LokSound decoder from SBS with a different sound file but was able to put a DDA35 sound file on that I downloaded from ESU's site. Can't do this without the LokProgrammer piece of hardware shown bottom right above. It isn't cheap but still not that expensive if you are going to install many ESU sound decoders.


Not only can you download the sound file now or later if you want to change it the LokProgrammer makes it easy to change almost anything else you need or want to on the decoder. I'll make some later changes later with JMRI and you can do a lot with it but the LokProgrammer makes complicated changes to the decoder easy and can do some things JMRI's Decoder Pro can't.
Another big change I made to make programming easier was to change the wiring on ( my test track ). It is an oval with some sidings and one of the sidings has been able to be changed from the main to a program track with a DPDT switch. That worked pretty good but for some testing I'd have to lift or run the loco out onto the main for some testing. Now I added another DPDT switch. Throw it one way and program with the LokProgrammer and the other way to program with DecoderPro. Then the other change was the other DPDT switch now makes the 'whole' layout the 'main' or the 'programming' track.


I've used this some and love it. I usually never have a loco on the layout unless I'm programming, testing or working on it so not worried about writing a decoder change to more than one loco at a time. I used it like this recently and it is so much easier to adjust the loco's speed for speed matching. Make a change and run it and time it around the oval till the speed matches what I want with any throttle setting. Also to use the decoder tester I only need to clip the leads on it to the track and I'm in programming mode with either DecoderPro or the LokProgrammer at the flick of a switch and can run the loco immediately. No more messing around on a short section of straight track.




Again, as in some other installs, I used a couple short pieces of flexible printed circuit board (PCB) as a means to add resistors for lighting. They work nice for this and other needs.




I upped the resistor for the cab light as I want it set to a really low level and might have gone to far (will change it if I have to). You need to use resistors with the ESU decoders for the LED lighting but it is also easy to dim the LED's using DecoderPro or LokProgrammer if needed. You can't make them brighter as the resistor will dictate the maximum brightness. Easy to make them fade in/out or lots of other lighting options (strobe, ditch, etc.).




There are a lot of wires just to the right of the decoder for other functions that I'm not using at this point but might so kept them long as there is room under the shell to do that.




Looks like a lot of wires but a number at the left aren't used at this point and might never be used. With all the frame milling out of the way this was actually one of the fasted decoder installs I've done. Probably less than an hour getting the initial wiring in place (add the cab lighting later).




Ran the loco to try everything out and love how it runs. It runs as good as anything else I have. So smooth. Not sure if it is the 2 motors, the decoder are the combination but love it.




I designed and printed front and rear light boxes to limit where the LED lighting shows.




I added the cab light since it was so easy and the crew requested it. It will be out underway and I could toggle that to be automatic If I needed to but for now it is controlled by a function key on the throttle and would probably stay that way even if it automatically is turned off under way.



Click on the image above or ( HERE ) to see and listen to the DDA35.

If you came into the build here you can go to the start of the build ( HERE ).

(NOTE: Keep in mind that this is N scale and these images if viewed on a computer can be larger than the real thing.)

Sumner