Looks good so far. The roof needs more work and the ends need the wheel splashes added, but, er, that's not a boxcar, it's a refrigerator car. :-[
BTW, the ice hatches on the roof are generally all open or all closed. To move fresh meat, they'd all be closed, while to move canned meat, they'd all be open as the car would be running as a ventilator. If they're flipped all the way open, it is at the icing platofrm.