Reply to "my first custom rail car"

Bill,  Glad you dove in.  You could place a 1/2" x 1/2" length of wood at the base of each wall.  That will strengthen the walls and provide larger surfaces for the adhesive which should make a much stronger model. May I suggest when you are ready to paint, apply a brown or black primer coat after assembling is completed?  That will give your paint a good base and if there is any bleed through(reverse weathering), the original colors will not be seen.  John in Lansing, Ill