The T-5 was a train note, as was the scarcer T-3 Montgomery. The T-5 is considered part of the 64 note "short set." Those not included are the T-1 through T-4, the T-27 and T-35, as well as the bogus ("enigmatic") notes formerly called T-47 and T-48. You said you had 66 type notes, and I was curious, if it included a couple from the "big six" or the other two, which ones were you able to acquire? Those are pretty tough.
Things were definitely different back then, before everyone had a computer and a scanner or digital camera. Collecting was more of a challenge, as one had to rely on what a dealer or shop might have had in inventory, or what might be found at a show. Now, with computers and the Internet, one has ready access to many dealer websites as well as online auctions like eBay, Heritage and others. Coming up with a "better example" is a bit easier, though it sometimes opens up competition for those choice notes. Over the years, wider access has enabled me to put together a collection I'm pretty proud of. Not the best in the world, but reasonably significant, especially for someone with limited resources.