Can't speak to IHC cars but on the old AHM cars the trucks were held in place with a plastic pin that pushed into a hole in the bolster. I usually had reasonable luck tugging at the truck with a slight rocking motion until the pin slightly raised out of the hole, at which time I could grasp the head of that pin with pliers and tug it out.
Now, having said that, my experience was also that you had a limited number of times to remove and replace that pin before the wear on the plastic would cause the pin to become somewhat loose. Or, sometimes the pin would break - the head would separate from the shaft. So the hole would be plugged.
I seem to recall at some point AHM replaced the black plastic pins with ones of metal that had ribs going down the shaft of the pin that were meant to grab onto the hole in the bolster, but my recollection is that those ribs actually accelerated the wear process if removed and replaced too often.
What I cannot recall is whether the hole in the bolster went all the way through the floor. If it does it might be better to remove the body from the roof (again relying on memory, body and floor were one piece, roof and "window glass" were another) and push down from inside on the pin, rather than pull on the pin.
Slightly OT but the plastic pins on the AHM freight cars were a little easier to remove because the trucks was smaller, and if you removed the wheel sets you could force a thin blade screwdriver between the body bolster and the truck bolster and force the truck, and thus the pin, up a little bit.
Sorry to be vague on some particulars but this is not something I have done, or thought about, in a long time.
Dave Nelson
