Howdy, just received a replacement Loco from Bachmann, but I had also sent a small bag of some kind of parts, metal things and track connector type things, at least that is what they looked like, and they must have been lost in the "shuffle." I sent them back because I did not know what they were for and wanted them to let me know. I noticed my track is a bit loose as the train runs around it...makes me think the could have been connectors of some sort. Anyway, will just order some more if anyone can let me know what they are and if Bachmann carries them...thanks in advance.
They are most likely the connectors that hold the track together. There are two types.
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_75&products_id=562
http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_69_75&products_id=563