Wazzou: Yours is one of the newer underframes, with the plastic center sill and brake detail. Most of mine were the original, all metal, version, and it was easier to cut the ends off than to grind down the center sills.
That's true of only the gondola on the bottom. The other car, the NP flatcar on top is the older version.
I just fabricated the fish-belly center sill and gussets from Styrene in addition to removing the hardware for the side mounted brake wheel and the brake wheel itself.
