Tomy/Trackmaster Serial Number types and meanings

They could simply be batch numbers or maybe even the serial number of the machine tools (moulds) used to make that train or component if there are different numbers on multiple parts.  This could be used to track down a faulty mould/machine if some components come off the production line with consistent faults or similar bearing in mind they will probably have multiple machines or sets of moulds on a machine producing them at any one time.

Hi Nigel.. your comments shown you are quite familiar with moulds and manufacturing system, nice to hear such idea, respect on you.  

As I heard about TOMY's mould, the mould number they marked at area which not so easily seen by customers such as inside body. Below picture shown mould number of my Annie. 

Each mould has several cavities, they also indicate cavity number as well.