I'm including a model of the Tunkhannock Viaduct on my layout. I'm attaching a pdf that is the template for the basic model. This pdf contains 2D scale data (readable by corel, adobe, flexisign etc). It can be used as a pattern for woodworking. It should be cut or printed at 100%, 1 ft =12"or 1:1, and will require a large format printer, or capabilty to tile. Each section is 12.00" long and 9.00" tall. The supporting structure will be 3.75" wide. I will be cutting this from 3/4 MDF. The deck will be 4.5" wide. This PDF contains no data for the deck, only the supporting structure.
There are 3 parts. Parts assembly is pretty basic sandwich. #1, #3 is stacked on #2, #1, #3/2 again, last #1.