The issues with semiscale GG-1s Ive had on 0-27 were a need to elongate the guide slots about 1/16", maybe less, to allow a tighter turn.(dremel grinder drum)
Now because of the fixed coupler, the coupler knuckle sits well to the outside of center, and at an angle too far to the outside. Now the two couplers, car & loco, may bind left to right due to position and angle sharper than the GG was designed for.
But a car with an articulated coupler, like a passenger car's can correct the bad angle because the articulation happens further forward on the car than a fixed coupler which has the same pivot point as the truck. It's tight, but the GG's pilot doesn't yank the cars off the curve anymore, nor does the pilot derail to the inside from a long train's weight. (I also increased the spring weight for more downforce... but that was more for a sharp grade transition )
I use a caboose with an articulated coupler shank at each end of a freight train since a GG1 was designed with the thought of not needing a turntable to turn around for a reverse trip along a branch. A run around the cars during unloading instead, saved tons of time for them. I just applied the thought to freight as well; never checked for prototype accuracy on that though.
I'm thinking there was still a slight 0-27 turnout issue, but I haven't tried in about 5-6 years, and can't recall it because right this moment as I have a pounding headache from the 140lb dogs 24hr whining over a female being in heat. It might have just been the coupler issue being worse around turnout guide rails. I also have larger than 0-27 on outer loops so I just stick to the Super O where it runs best, looks best, with the Broadway Limited streamline cars.
Brunswick was more likely to be freight than Tuskan, but a Brunswick with matching heavy Madisons is my favorite for moving passengers.
Other new age semiscale options are RMT & Williams by Bachmann(if any are left). Can motors there also. Nobody does an open frame I know of. Frank at Timco can fit a can motor to an old open frame truck by Lionel or Wlliams for you too.
My fav has been a K-line (none here but Ive heard of zinc pest). It tracks so well I sold off my MPC Lionel (which was actually better than a few PW versions Gramps let us run "all willy nilly" (others required a soldiers attention before you could look at them close, let alone run them)). The k-line has better detail and paint than others preceeding it. I don't know if the present Lionel is the old K-line version or not. All are very similar and it takes a side by side comparison or a lot of detail knowledge to make a judgement what is what. (Williams used to have the name on the inside of the shell roof. MPC Lionel had a casting number. I haven't had the K-line apart except for one time and didn't notice. RMT...?? (likely lowest cost, same basic quality on electro&mechanicals from my one experience.)