Some examples of scenes from

Some examples of scenes from a layout long gone.

12 inches:

9 inches:

Lift up section down:

Up position:

Tom Johnson's Logansport and Indiana Northern

This may be the best narrow shelf layout on the planet:

https://forum.mrhmag.com/post/logansport-and-indiana-northern-12191000

Scroll down for pictures Tom posted.

Variable Width

Those are 2 great examples!

Also consider varying the width, where you only have single track running through the country 8 inches is plenty, where there are sidings or buildings make it wider. If you plan it out you can have a narrow shelf on one side of the room with the wider one on the opposite side. The result is that you are using the same footprint in the room but still have room for more industries.

The best has been said: Tom

The best has been said: Tom Johnson's Indiana shortline is THE reference.

A 9 inch width for this scenery (HO scale)

Width...

It's not the width of the shelf that matters, its the depth of your scene. 

Randy

 "how much a guy can get into

In S scale I'm building a 4 track staging yard on a 12 inch wide shelf. 12 inches is  64 feet in S, 87 feet in HO and 160 feet in N scale so for N scale 12 inches would be quite a bit of scenery. You need 22 inch HO shelves to get the same amount of scenery. Keep in mind that a layout doesn't have to be the same width everywhere, it can be widened at industrial areas then narrowed back down between points of interest. I've seen HO layouts as narrow as 8 inches in spots and they functioned fine....DaveB 

Quite a lot..

This is a screen shot from Sketchup, each square is 87' or 1' in HO. It would be easy to model this factory in the first foot using a photo backdrop with added models for detail, move the squares back and give up some green space and a model could be used instead of a photo.

A concern I have when considering shelf width is the distance from the closest track to the edge. Bumps, derailments and shirt sleeves tend to send equipment over the edge so a scenery buffer can prevent loss.

The above shows a 12" wide module the sixth yard track wasn't added to allow for some buffer, just in case. The track at the back was against a backdrop.

Also don't forget height and reach.

Eugene

Ken, thank you for taking the

Ken, thank you for taking the time to share those links and photos. it was very helpful.

delayed reply but your photos

delayed reply but your photos were helpful, thank you.