Atlas SD 35 coupler height

[NtheBasement]

I bought an Atlas "gold" B&O SD 35. I love a couple of things about it: this is my first "scale speed" loco and it is so nice not seeing it rip along at shinkansen speeds. I also like the sound compared to my old econami-equipped loco. But I can't pull a consist because the couplers are too high. Has anyone else seen this? Is this going to be a problem if I put in a microtrains coupler? The MTL chart says 1015 with shim on top for the 2000 release - this is not from 2000. Is that the right mtl?

This height mismatch means I can't actually pull a train. Pretty sad when something won't run out of the box, whats going on over there at Atlas? Or am I missing something? [ Guests cannot view attachments ]

[Bendtracker1]

Looks to me like the shell is not fully seated.
That or something is keeping the shell from being seated properly.
You shouldn't see the gears or the top of the brass axle tab.

[Jimbo]

I agree… looks like the shell isn’t fully seated. Check out the photos on Mark’s (aka @spookshow ) site.

https://www.spookshow.net/loco/sd35ln.html

Per his site, there wasn’t any noticeable change in shells since 2000, so I’m guessing the guidance you received on MT conversion is still valid:  “According to Atlas, there were no changes to the shell with this release (so, older shells should presumably work with this newer chassis, and vice versa)”

Jim

[NtheBasement]

Thanks, the shell is indeed the problem.

Pushed very hard on the fuel tank, nothing.  Pushed a truck and hey, that end went up but the other one went down - it is seesawing on something in the center.  Pulling the shell off required an alarming amount of force.  There is nothing protruding from the shell that would act as a seesaw fulcrum.  Highest thing on the frame are the DCC board components.  Sure enough, if I remove the DCC board the shell seats all the way and coupler heights are good.

The DCC board visibly different from the one in Spookshow's photo.  Not sure what to do next, other than see if I broke the DCC board yet. 

[NtheBasement]

DCC still works, tough little bugger.  I've started the return process on Atlas's website.  Wondering if I should try a "no sound" version and maybe replace the speaker with tungsten.

[peteski]

The DCC board visibly different from the one in Spookshow's photo.  Not sure what to do next, other than see if I broke the DCC board yet.

Interesting. Spookshow's photo does show what appears to be components on the decoder protruding over the top of the frame.



Any chance you could take a photo of the chassis with the decoder installed?  I'm curious what is installed there.

[signalmaintainer]

Looks to me like the shell is not fully seated.
That or something is keeping the shell from being seated properly.
You shouldn't see the gears or the top of the brass axle tab.

@NtheBasement, based on changes to the light board/motherboard Atlas has made to accomodate E24 decoders, if the SD35 shell still has the old-style light headlight/numberboards, it probably will not fit over the new lightboard. I have found this to be the case with older GP38 shells and the new Atlas GP38/40 chassis. Only shells with the new headlight/numberboard inserts will fit -- and they'll break sooner than remove easily from new shells. Disappointing that Atlas QC hasn't sussed this out yet.

Good answer too below by @Curtis Kyger .

[Curtis Kyger]

Yes.  I believe the decoder board capacitors are sitting high and do not allow the shell to drop into place.  I think I read somewhere on The RailWire that someone had removed the factory decoder boards, replaced it with a hard wired decoder and all was well.  Reuse the board on another locomotive.  Bad answer.

[NtheBasement]

There are differences but nothing obviously sticking out.  The number board/headlight stuff is also different.  And another clue or red herring is on the shipping info from Lombard: DCC/ESU LokSound V5 Equipped.  Maybe the V5 is not so good.
[ Guests cannot view attachments ]
[ Guests cannot view attachments ]

[NtheBasement]

Yes.  I believe the decoder board capacitors are sitting high and do not allow the shell to drop into place.  I think I read somewhere on The RailWire that someone had removed the factory decoder boards, replaced it with a hard wired decoder and all was well.  Reuse the board on another locomotive.  Bad answer.

That sounds right to me.  I have no intention of hard wiring a decoder.  After spending that much $$$ I don't want to risk it, nor should I have to.

[signalmaintainer]

Just a WAG, but perhaps ask Atlas if the new lightboard/motherboard for the ESU/Zimo/Digitrax E24 decoders will work with the new SD35 chassis. Either the version that comes with the new SD-9s or the new GP38s. They are significantly different from each other, but both have E24 receptacles. That ESU decoder shown seems to be the issue.

[Kuchler10]

I have both numbers of the B&O release, also with DDC and sound that have the same problem. I'm going to shim the couplers temporarily until I can find a solution.

[tehachapifan]

On some of my older DCC-ready Atlas and IM locos (before they switched to the newer board design like pictured above), I don't believe the nubs on the frame touched the top of the shell. On those locos, some of the components on the ESU board that I installed extended above those nubs as in the above pic, but the shell still seated all the way down. So. it may not be as bad as it appears and some really careful Dremel work inside the shell where the tallest components are might do the trick.

[peteski]

There are differences but nothing obviously sticking out.  The number board/headlight stuff is also different.  And another clue or red herring is on the shipping info from Lombard: DCC/ESU LokSound V5 Equipped.  Maybe the V5 is not so good.

Weird! The decoder installed in your model, and the chassiss itself are identical to the one  in Spookshow's SD35, and he doesn't mention anything about the fit (or coupler height) issue.

[garethashenden]

There are differences but nothing obviously sticking out.  The number board/headlight stuff is also different.  And another clue or red herring is on the shipping info from Lombard: DCC/ESU LokSound V5 Equipped.  Maybe the V5 is not so good.
(Attachment Link)
(Attachment Link)

The black thing in the shell, presumably held there by the tape, can it be removed? I'm wondering if its a little further back in the shell than it should be. But I don't have a locomotive to compare it to.