I have never used them...but I have heard a lot of good things about them, one being very accurate for era: Ask them.
http://bethlehemcarworks.com/Products/index.html
Frank
I am on a search for one pair of heavyweight passenger 6 wheel trucks b ut to no avail. I did find that Bethlehem Car Works has 3 or 4 versions of PRR Type 3C 6 wheel heavyweight passenger car trucks available. Has anyone used BCW 6 wheel passenger trucks with walthers RTR passenger cars or their original heavyweight passenger car kits they made up till about 1978?