Bob,
The TT in the latest design is the 28" Millhouse Model Works version.
Your link to the RH drawing is broken.
Here's the link to the product page. The photos show 3-12 stall versions.
https://altoonamodelworks.net/...up-type-round-house/
Here's the only link I could find to drawings (5-15 stalls).
https://altoonamodelworks.net/...-footprint-drawings/
Here's the link and a photo for the 55" version I've been using.
https://altoonamodelworks.net/...-wall-55-to-back.pdf
As you can see, it shows 5 stalls (not 3) with measurements for 28" and 30" TTs. The configuration in the latest design uses the numbers for the 28" TT because SCARM does not have a 30" TT. However, the only difference is the 1" length of the whisker track, the RH doesn't move.
Even though I still don't think it's a viable option, I added a photo of what it would look like with the 34" TT. The distance from the center of the TT to the rear wall increases from 55" to 63", meaning the RH would stick out in the aisle another 8". The distance from the top corner to the tabletop would then be only 16" and the bottom corner 18", a tight squeeze. Although the 34" TT would allow you to add the 6" front extension to 1 stall for the long engine, I just don't think you'll want to extend the peninsula that much.
Photo deleted upon request
Since SCARM doesn't have the 30" TT in the library, I can't show you exactly how things would fit. However, since the Altoona drawing includes both the 28" and 30" TTs and the RH doesn't move, I "think" the only things that change are the lengths of the whisker tracks going to the RH as well as the tracks leading to the coaling tower. Since there are 10" straight tracks in both places, it should just be a matter of substituting 9" tracks (two 4.5" tracks if you want to use sectional tracks).
One last thing. I'm not sure why you like the Altoona model over the Korber model, and it really doesn't matter, but the only advantage to the Korber model for me is that you could add the rear extension to the middle stall to accommodate your longer engine. Personally, I don't think that would be too aesthetically pleasing if that were to stick out on the peninsula, but it wouldn't shrink the aisles. Both models appear to have essentially the same basic footprints, but differ in where to put the extension. The 3" rear extension for the Altoona model is an option, but it still won't accommodate the 30" engine.
