@ScoutingDad thank you very much for that comparison! They actually do look ok next to each other. Just to clarify- the MTH premier Husky stacks run on o-42?
really though, thanks for posting some of that as I am working on compiling container dimensions, types of “connections”(molded on pin, removable) length and width between pin holes(I/a), and well car dimensions and how the containers either attach or just sit in the well. I am missing the Lionel well car and container dimensions their Husky stacks(already have the s-Scale Maxi stacks well and container sizes) and the well sizes for the numerous Atlas well cars
Regardless, @250rman said he is looking for some scale Maxi stacks. While I can’t necessarily help you there as I have none(wasn’t Atlas coming out with those?), if you’re into intermodal(which it seems that you are) I think that taking a look at some scale well cars and some other scale intermodal types might be helpful:
K-line Thrall(scale 40’ well, Scale 40’ Containers) followed by the Menards well car(which I believe is also based on a Thrall well car).
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K-line CSX Gunderson, Lionel Maxi Stack(clearly not scale), Menards well car
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K-line with 48’ container on top. As already stated by @Jeff78rr , the measurements on the side of the car state it’s a 48’ well-clearly not the case
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K-line Thrall, Menards well car, K-line Gunderson. All nominally 40’ containers however...
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Length comparison: K-line Gunderson(shown) and K-line thrall(not shown) 16.5”. Menards is 17.5”. Thought this picture also made evident that the Menards containers are shorter(9.5”)
Cross compatibility:
**NOTE** when solely considering containers, the K-line Gunderson And Thrall can be used interchangeably for compatibility comparisons
K-line 40’ container in Menards well. Nice thing about the Menards well car is there are no pins protruding out of the well, allowing for more compatibility. K-line ( snug but work) and ROW containers(not shown) fit w/o modification 
Weaver 20’ container in Menards well car & K-line Thrall-first 2 pics below. First, instructions to make Weaver containers workable in K-line well cars
Without modifying, the containers will wobble MenArds and k-line cars- also will shift up and down in the K-line wells as they prototypically have girded bottoms. The Weaver containers have pins molded in bottom of each corner and a bottom with a protrusion to attach to Weaver flat cars. Pegs are relatively small, though. To make the Weaver containers work with K-line well cars, one can make the following non-Premanent modifications:
MODs- remove Weaver container bottom by unscrewing it, get .60 styrene or remove an ROW 20’ container bottom(they fit perfectly), cut/drill holes in each corner of the new bottom, affix to bottom of container with double sided tape or small amount of sticky tack(PIC 3 below). Get another piece of styrene that’s 1.5” long and fits the middle of the K-line well, on both of the 1.5” sides, cut a hole were the two Weaver containers pegs will be( PIc 4below). Finally, tape that piece of styrene in the middle of the K-line well cars. The Weaver containers should now adequately balance.
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PIC 3
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PIC 4
MTH premier 20’ . Molded pins on bottom, better fit than K-line. That said, unless one would grind/sand/dremel those pins down, the looser fit would probably cause some wobbling with any combo of MTH premiers
Atlas 40’ in Menards well. The detailing on the doors of the Atlas container exceed the length of the Menards well
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Atlas 40’ in K-line thrall. Looks can be deceiving, this will wobble due to a loose fit
MTH Premier in K-line Gunderson- same problem as with the Menards well. Compounded by the K-line well pins
Atlas 40’ on top of K-line 40’ works. The reverse won’t
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Other intermodal options worth considering:
**NOTE** some of the below examples require modification to cars and or containers. With careful measuring they turn out nicely. Any modifications will be noted
Weaver 14.5” bulkhead flat with Atlas 40’ container(MOD:Weaver flat required 4 holes to be drilled into the bed- technically you might be able to get away with just 1 that are on diagonally opposite sides if just going for a 40’) and K-line 13.5” flat(removable bulkheads) with MTH premier 20’ and Weaver 20’(MOD:K-line flat requires 6 holes, non-permanent mod to Weaver container- required removal of bottom which was used to attach to weaver flats, replaced bottom with styrene but depending on what you’re going for that is not necessary)
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Lengths of the cars is different, but all containers are scale so they match-up in length. While the MTH container is a bit wider, it was slightly crooked in this picture. this combo looks just fine on the rails.
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K-line 13.5” flat with two Weaver 20’ containers and Weaver Bulkhead flat with K-line 40’ container. MODS: see the description of the picture above the previous picture
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K-line 13.5” flat(bulkheads removable) w/ Atlas 40’ container, same type of K-line flat with K-line 40’ container, Weaver Bulkhead flat with two Weaver 20’ containers(MOD: Weaver Flat required 6 holes drilled into bed after careful measuring- that includes the 4 holes for a 40’ container. Weaver container bottoms removed and replaced with styrene
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Weaver bulkhead flat w/ Atlas container next to Atlas Front Runner with 45’ Pines Trailer
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K-line 2 unit TTAX Spine cars. THese can be expanded to the prototypical 5 unit- nothing like the early 90s Lionel TTAX. In terms of K-line containers, one of these can fit any of the following combinations: two 20’, one 40’, one 48’, one 40’ Trailer chassis w/ or w/o container. K-line’s 9’ Heavy Hauler trailers are NOT compatible with these unless modified
Spine car with 40’ Trailer next to AtlasO Front Runner with 45’ Pines trailer
Hope that helped a bit or helps someone. Good luck!