Hi Tony,
It's been a long time since I bought any brass freight cars, but the two screws on either side of the coupler pocket were usually 1.4mm, the same as on locomotives and passenger cars.
See you in Naperville,
Andy
Andy Sperandeo
Executive Editor
Model Railroader magazine
asperandeo@...
262-796-8776, ext. 461
FAX 262-796-1142