Here's a 40' shipping container model that is sized for an N scale model railroad. The design was done in OpenSCAD. The size is 76 mm long by 17 mm high by 15 mm wide.

I used the following settings on my MakerBot Replicator2 to print this design in PLA. I didn't use a raft and support is not needed.

Infill = 10%
Layer Height = 0.200
Shells = 1
Feedrate = 40
Travel Feed = 55
Temperature = 220

Once all the pieces (2 sides, 1 top, 1 bottom, 1 end and 1 doors) are printed, you will need to assemble them to complete the shipping container. Here are some tips:

• Use cyanoacrylate (Super Glue) to glue sides together
• Lightly sand the edges to remove any burrs before gluing
• Fit the sides flush with the bottom and between the end and the doors
• Glue the top on last