Yep — National C-1 trucks.
In case there are lurkers who don't know...
From
http://pennsyrr.com/index.php/modeling/200-alan-curtis-models-f30a-and-f30d-flat-carsThe F30d's that were converted to TOFC service had Pennsy class 2E-F25b trucks. I was afraid this would be a compromise for this model, but in October 2005 Atlas announced an N scale Hart Ballast Car with "new 70 ton trucks". These are, in fact, National C-1 70-ton friction bearing trucks -- a very close match for the 2E-F25b! Atlas will be offering the truck as a parts item (#22052). Pricing and availability have not yet been established. (The ballast cars are due in March 2006.)
F30a cars had 2E-F10 double-truss trucks, with the exception of #475265 that had 2E-F13 double-truss trucks. Bowser makes a 2D-F8 (#33145) which is very close -- the springs are slightly different and the 2E-F10 wheel base is 2" longer (negligible in N scale).