Cantilevered scenery or buildings?

You can use photos or make a textured backdrop. Here is example of textured backdrop. Its about the thickness of cardboard.

Here is a work in progress shot.

You may want to consider a mix.  A mountain tunnel for a portion that will help transition the scenery to the textured backdrop.

Bill D

Steve,

On the Pinnacles Peak project, I extended several rocky ledges out over the tracks and/or scenery below, up to about a 4" overhang. They just need to be solid looking enough to justify their existence geologically.

I glued chunks of Styrofoam to the basic hardshell cliff to create the overhang, and then covered everything with a layer of Structolite plaster. They could just as easily have been added to the backdrop itself to create the overhang over the tracks nearest the wall.

Jim

Also works for buildings - upper floors that overhang just a couple of inches add a lot of depth to building "flats" without creating clearance problems on tracks below. Again, the overhang has to look believable, architecturally and structurally.

Jim

Niceeeee Bridge!!

What good is a building that cantbedelivered?

Scrappy

Some excellent suggestions - thank you very much..... and Elliott has me worrying about deliveries now.... 

Hi Steve, I think Bill Bramlege did a piece in OGR about scenic panels that mounted to the wall, an would overhang the main line. You may want to look that up.

One thing about using Styrofoam as Jim has done is that the result is fantastically believable yet notice how the foam acts merely as the support and does not resemble the finished product. 

I think that given the quality of the finished stone work using Styrofoam may seem challenging when in fact the randomness of stone work makes using this technique very doable. Scenery is well random. There are no wrong results although with some practice the artistry emerges.