not much to add but wanted to echo Mo Ma's kudos and thanks to WOD and also welcome him back. new years and birth days back to back? epic as well I hope.
thinking maybe the chemical abbreviations (au,ga,ga,ag,cu,au,ga,au,ga) might be used in solving the string riddle but have not gotten anywhere with them. Electrum is the only thing i've found that maybe contains all four elements but dont see how that might relate to a toy or model train thingie where some kind of key could be. cant help but to keep at it. most intriguing.