For anyone who may be interested, there is a 3-D print “CamPac” coupler box available for USA Trains F3 A and B unit.
A pair of boxes and mounting pedestals are provided for each F3 loco, whether an A or B unit.
See “Installation Guide USA Trains F3 & CamPac Components”
If interested in obtaining any of these boxes, visit Colin Camarillo’s Web site CamPac Box page.
-Ted