This article is from the Model Trains FAQ, by Christopher D Coleman with numerous contributions by others.
This depends on the make. Usually the best way to catalog them is
first by "make", then by "catalog number". This usually appears on the
item, but not always, and sometimes even the wrong one appears. The
best way to make sure you have the correct number is to buy a
"checklist and price guide" from either Greenberg Books or TM for each
make. They list all the numbers produced with a brief description of
each. For the larger makers like Marx, Lionel, and Flyer the lists are
separated into major periods of manufacture, such as Pre WWII, post
WWII, Post 1970, etc. The hierarchy of my train database is:
Maker
Period
Catalog Number
Date Purchased
In some cases it can be a bit of an art but is usually straight
forward. Early trains (1910's and before) and "economy" trains are the
hardest to classify as where they often have no markings.
 
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