I bought some 1/16” thick scribed siding (3/16” spacing) from Micromark.

These pieces are 24” long, but only 3 1/2” wide, so I needed to cut a bit over 5 pieces for each side, 2 for each end.  

I glued them in place using contact cement, making sure that I butted the edges as close as possible.

The roof is made from two sheets of .060” thick styrene.  

On top of that, I added some .250” x .060” styrene strips to form the carlines.  The end pieces are 3/8” wide cut from a .060” thick sheet.

I got some boxcar door details from Ozark Miniatures. 

The door was cut from the wood siding and plastic strips were added to frame it.   Before they were glued in place, I embossed some rivet detail.

Finally, a .060” x .250” strip was put in place for the header.

Ladders were built from .100” x .125” styrene strips and brass bent to shape.

Brass strips form the end walk supports.

The same brass strips were used to form the stirrup steps at each end.