John, here is a Millhouse Rivers 34" turntable with an extended 4-stall Altoona roundhouse overlay. As you can see, there appears to be room. However, you asked if the setup was realistic and the short answer is I don't believe it is.
AFAIK, there's nothing realistic about curved whisker tracks.
There's also nothing realistic about the long red track or the extreme curve of the long purple track. I can't figure out how you intend to use either one.
You have a 34" turntable feeding whisker tracks that are over 43" long. If you try to place whiskers that close to each other, you may need those 43" because engines need to be far enough back so the front ends clear each other as they move in and out. How many engines do you need to have on the layout at any given time?
The yard is basically limited to backing consists in since there is no way for engines to move around the yard and there are no lead tracks to work a consist without fouling the orange mainline. To really do that, you'll need to approach the bridge from the bottom, then back into the yard, drop the load, come back out, back onto the turntable, etc. If you want a switcher to do the work, you need to park the consist on the mainline and the switcher will have a really interesting job trying to break the consist apart and store the cars. The whole thing seems convoluted to me, but then I'm no expert on yard design.
