Congrats on the new train room. Looks like a great space to work with. Plenty of great guys here who will chime in also. You can do a really nice around the room layout maybe with a couple of peninsulas, starting to the right of the stairs and around the three walls. Leave the closet area free (keep the CEO happy), for a work bench and maybe a couple of chairs.
Looks like a typical attic room. If I read your measurement correctly the walls are 3'6"? That's a decent height for bench work. Track plans are very subjective and many of the experts can chime in. Use the largest radius you can fit. Everything I read says 060 min- 072. Do you like to loop run or point to point and switch industries? I would do both personally.
Don't forget AC and heat.
Good luck- Bob
