“bUILT IN 1928, THE ft-n CLASS FLATCAR WAS MODIFIED IN 1943 TO SUPPORT AND TRANSPORT THE CENTER WING SECTION OF b-29 VOMBERS FOIR FINAL ASSEMBLY.” From the MTL description.

1 x ATSF Flatcar #90949

2 x UP Flatcars. #57066, 57074.

includes resin and wood parts to assemble the load.