NS box car question

[Red Rock]

Hi all. New guy here with a question I hope you all can answer. From what I understand NS uses a car classification system based on the old N&W system. Southern never used such a system but the heritage cars have been assigned class numbers. I'm trying to piece information together about a particular 60' double plug door car. They were from the Southern 17000-17499 series but are now numbered for NS in the 465400-465510 (this is somewhat of a guess, the specific cars I have questions about, fall in between these NS numbers). So here are the specific cars in question, NS 465506 is a BS-30 class, NS 465509 is a BS-29 class, and NS465450 is a BS-29-A class.  However they all look identical and the car data seems the same for them. When delivered from Bessemer the cars had three variations within the run. The first group had 70-ton trucks, then the second half of the delivery had a heavy duty floor installed, while a portion of this group also was updated with 100-ton trucks. Could this account for the three different NS class groupings? (I haven't had any luck finding a book which explains how this class system works).

[Michael Knight]

I'm not exactly sure, however, your reasoning makes sense. This could indeed account for the three different class codes used.

Welcome to the forums, I am a fairly new guy here myself.

[Red Rock]

Thanks for the welcome , and for the feedback on my question.