"Low relief" is the model railroading term used to describe a building with only the front (or the back) visible. Sometimes part of one or two sides can also be seen, but you can't see behind the structure. It is for this reason that low relief buildings are very often positioned at the edge (or near to the edge) of a scale rail layout.

When making your own model railroad, the first thing you must know about is scales. The size of your trains and the size of your buildings and structures will all be based around the same scale. So if you choose HO scale for example; you will need to run HO scale trains, include HO scale structures and HO scale track. Mixing HO scale with N would look strange and unreal.

 Once I chose the type of building I wanted. I printed them out and glue them to card board.
I then back them with 3mm MDF board, this gave me a 3D look. When placed next to building glued straight to the backing board. Some of them were pack out with another 3mm to give a street scape of alleys

The bridge was a little tricky as print to scale and having it fit in with both the width of the road and match existing building next to it.

Once all the building are fixed in place I replaced the backing board with the rail viaduct and fencing in front it all look just right!