Mixing shells and mechs - IM SD40T-2 on Kato SD40-2

[ryan_wilkerson]

I have a Kato SD40-2 mechanism that has a cracked set of hand rails and walkway. I started to look for replacement parts on the Kato website and then realized I had an Intermountain SD40T-2 shell. So I lined it up and it looks like the trucks are in the right place and would functionally work. The bad news is that the IM body is more narrow than the Kato mechanism so some or both would need some filing to make this work. Has anyone tried this? Is so, how did it workout? I don't want to start filing things down and it not work for some other reason!

[randgust]

I put an IM SD45-2 shell on a Kato SD40-2 (old style DC) mechanism, does that count?   I wanted to be able to MU my SD45-2 flawlessly with my old SD45's, that did it.  The IM mechanism was much faster than the original Katos.

http://gustafson.home.westpa.net/5649_Flagstaff_2.jpg

And it's also 20% heavier than the original IM frame.

[ryan_wilkerson]

That definitely counts Randgust! Any details you can share about making it fit?

[randgust]

I'll update this later this weekend when I can take some shots.  I don't remember it being particularly difficult.  I did put a full Richmond Controls light + strobe package in it though as it is a lead unit.

[ryan_wilkerson]

I'll update this later this weekend when I can take some shots.  I don't remember it being particularly difficult.  I did put a full Richmond Controls light + strobe package in it though as it is a lead unit.

No rush, looking forward to see the guts of the project.

[LV LOU]

I put an IM SD45-2 shell on a Kato SD40-2 (old style DC) mechanism, does that count?   I wanted to be able to MU my SD45-2 flawlessly with my old SD45's, that did it.  The IM mechanism was much faster than the original Katos.

http://gustafson.home.westpa.net/5649_Flagstaff_2.jpg

And it's also 20% heavier than the original IM frame.

Randy,how long is the wheelbase on that SD45-2?

[Robbman]

Same as a SD40-2

[LV LOU]

Same as a SD40-2

This would be useful info if I actually owned an SD40-2,if I had one,I'd be smart enough to measure it myself..

[randgust]

I measured the Kato SD40-2 model out at 57' 6" from the center of the outer axle to the center of the outer axle on the opposite end.

I'll post photos later of what I did to the chassis and the shell.

[randgust]

OK, here you go.  I did file off a bit off the sides, and ground a bit off the inside of the shell itself:





The other stuff in there is some more weight at the back of the shell, a Richmond Controls light and strobe package (red wires).

[ryan_wilkerson]

Thanks Randgust,
When I attempted putting the shell on, it felt like the middle section was the tight spot and your photos and description confirm that. I like that you found some extra space to add more weight. Does your "20%" heavier included your added weight or is that just the comparison of the stock Kato with the IM mech?

I also got an email from Jeff that had a link to the different sizes of SDs and it looks like the SD40-2 is a perfect match for the SD45-2 (and SD38-2). The SD40T-2 shell I have is close but not exact. It might be functionally OK, we'll see.

[randgust]

The old Kato mechs are made out of a heavier alloy - that's before the weight was added.

I was so dissapointed with the original IM all the way around; both paint and mech.  This was a 'woodsman's axe/Ship of Theseus' project, I rather love it now.  This and the U36C are the most modern power on my ATSF layout.

[johnh35]

Since IM used an adaptation of the Atlas SD50/60 to power their SD40T-2's, couldn't the SD50 be modified to use the SD45-2 shell? I was under the impression they were they same mech.

[ryan_wilkerson]

According to the page below, the SD50/SD60 are close to the SD40T-2 and SD45T-2, just about 4" so maybe that is a good solution for the SD40T-2. The problem is the actual fitment of the model. I just tried to put an IM SD40T-2 shell on the Atlas SD50 chassis and it's too long to fit in the shell. It's not even close and since the screw/nut is close to the ends, I don't think milling the ends would work well. I also don't think the Atlas mech is much of an upgrade to the IM. On the other hand, the Kato SD40-2 is better than the IM SD45-2 mech, in my opinion.

Model      CouplerFaces  EndPlates  Bolster C/L
SD40-2    68' 10"           64' 8"        43' 6"
SD45-2    68' 10"           64' 8"        43' 6"

SD50       71' 2"             67'            45' 7 1/2"
SD40T-2  70' 8"             66' 6"        45' 5"

http://www.trainweb.org/utahrails/drgw/locolength.html

[randgust]

I put an Atlas SD50 mech inside my old Lima FP45 shell to make an FP45 long before Athearn ever came out with theirs.

I have it MU'd with a pair of Kato SD45 mechanisms in F45 shells made out of Limas as well.

SD50 was significantly faster, and pulled less, than the SD45's.  Under full slip it also 'clicks', which is an Atlas SD50 disease on gear tolerances.  I've added diodes to drop the motor speed and added weight to increase tractive effort, but if I had another Kato SD40-2 (DC) I think I'd swap it out.  One of those things that works, yeah, but if you had a choice to do it over you'd do it right.   It runs good...but it doesn't run great.... here's the three at work:

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I've got seven SD45's and one SD40-2 mech; three C30-7's, that Kato fleet is my backbone.