My 3rd certificate is in the category of Model Railroad Equipment being Master Builder – Cars, or as I like to call it “cars.” My thoughts are recorded in the March 2017 issue of the NMRA Magazine. You can read the PDF here.
The handout for the clinic I did about making my own molds and casting the frames is here.
Here is some of the info I included when having my cars judged. Click on the picture to load that specific page. Three of the cars I did not create a special PDF like the others and they are seen below.