You did find the right place—thanks for showing up and asking—keep the posts coming!
We have been down this road before.
These are not collectable.
There have been many speculations as to the origin of the so called “train track marbles”.
The most common explanation is that they were intended to go to a factory that produced “fiberglass”.
There were many marbles---millions upon millions that were made for the explicit use of manufacturing in a variety of ways from polishing steel--etc from foundries to to use in the manufacture of fiberglass.
The tinkle that you hear when you shake a can of spray paint is a good example.
Marble—On my friend and keep coming back.