Thanks for the info! .. What I have are Rich Art Trains 712 Observation
I did find the 6 wheel prewar copper trucks for from our friend Jeff from the Train Tender...
I won't know until the parts come to see if when Rich Art Trains made them he designed them to fit either 4 and the 6 wheel truck . Because I have read he made them both ways time will tell thanks!
I hoping he made all his shell the same .. Time will tell...