Generic flat car for On30

[nkp_174]

For your next car, I would suggest that the lumber dimensions are a bit chunky.

Side sills were frequently 4"x8" for small cars. 10-14 ton capacity 26'-30' cars frequently used the slightly larger 4"x10" sills, and 20t+ capacity cars used 4"x10", 5"x12", or 6"x12" side sills. Typically, side and center sills were the same size while intermediate sills were one size smaller (passenger cars excluded). End sills were usually a little smaller, with the bolster and draft timbers/irons carrying much of that load.

Decking was commonly 2"x8" for smaller cars and as heavy as 3"x14" for larger cars.

For really short cars like the above, I'd consider using a king post (and single needlebeam and pedestals) instead of queen posts. You can certainly justify the heavy timbers as a means of avoiding truss rods.