I bought a couple of acrylic car kits from Andre’ Schofield; they are basically an inside form for a 30' boxcar.
I glued the pieces together using Weld-
The sides are 7/32” thick, so they’re plenty sturdy -
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.