Casting numbers *LINK*

For the last 10 years or so, I have been collecting casting numbers from various California narrow gauge builders and operators.
While in some cases there are obvious patterns to the numbers assigned (it takes about 20 different numbered castings to build a single Carter 15 ton flatcar) there are also many many cases of a number which has no apperent rhyme or reason. In one case, I have 5 different number for the same part. In other cases the numbers range too widly to be considered part of a single group.
Additionally the casting numbers were commonly lead or other soft lead castings, attached to the pattern using the paint the pattern is painted with as glue. They are easly lost and or changed.
For every casting with a number, there are several without...
Randy Hees