Around the room

An around the room layout would be better than the 4x8 island and accomplish your goals.

"An around the room layout

   I agree. A typical extra bedroom is plenty big enough for a nice around the room layout. I've even had an O scale layout in my 9.5 by 15 foot room. If you keep your benchwork around 18 inches wide or less you'll still have a nice size center of the room space.Around the walls gives the longest possible run and more length for sidings and spurs.The only way I'd go with a central island type design is if I was modeling a busy city scene where I needed to crowd lots of track into a small space to capture the feel, otherwise I'd spread it out and string the scenes along the walls....DaveB

Scott Perry’s HOG/Better Beginners Layout

In that space, I’d take a hard look at the Heart of Georgia layout by Scott Perry. Fits that space nicely, uber-expandable, and uses only slightly more lumber than a 4x8 but gives longer runs and broader curves. 

Mike in CO

Swap things around

Yup run the layout around the walls.

How high up is your layout?

The work bench over the top of your staging yard seems to put your yard way to low or you plan on sitting on a high stool or standing at your work bench?

Staging yard can go along one wall with low scenery in front of it. Make the yard seem like a freight yard so it is part of the layout not separate

Putting the layout up higher will give you all kinds of storage space under it.

Having dealt with 16 inch isles on a much earlier layout, they get old really fast even if you are on the thin side.

You don't show the entry door or a closet. The entry door is easy to work with by putting in a swing bridge using a standard door hinge.

Jack

Something like this then?

So, something like this then? Forgot to mark it on there but the backdrop would curve around behind the roundhouse and then the left side of the peninsula. Give me a place to hang clipboards with the switch lists and minimize the number of people in that walkway to just those that need to be in Logan. Workbench would be built underneath peninsula from where it says 'computer' over to the tool chest. Room access would be via a swing-gate on the bottom-right corner.

Your isles are still narrow and you have very little space

for scenery. I would make the peninsula narrow and probably hinged to drop down out of the way if you really want to keep it.

Your engine service area / turntable takes up a huge amount of space and that yard is pretty short. 

Your yard layout is correct design wise for constant switching action. 

I try to balance yard capacity with industry siding capacity. 

You only have one industry to switch. 

The other catch with building this type of layout is that rooms are not standard sized. You will have to make a system to allow for 2 or 4 filler pieces to expand to the exact space. 

I went old school and built my layout based on a 5’ x 6.5’ section because I wanted it to be movable. Then I put it in the bedroom and realized that it only fits in the room one way. It works. But I have a narrow squeeze between 24” wide isles. Thankfully having a 60” layout high works in my favor because I couldn’t fit through the narrow part at waist high. Having another fat guy in the same isle would be uncomfortably tight. The reality of this size room is that you either cram in track or you leave enough people space for comfort, you can’t do both. 

This better?