Custom Bogie Sounds

[tads1]

Hi,

Since purchasing T12 Ive noticed lots of stock mainly BR stuff could do with better bogie sounds,like the old unfitted box vans.
I have all my samples sorted,im unsure what I should be looking for?

If I bring a piece of stock up in CMP that I would like to add sounds to,what next?I.m stuck
am I looking for some kind of table,or engine spec?

Any help appreciated

Daz