Hello!  I'd like to introduce myself... I'm Dennis, I'm 60, and I've loved and owned Lionel O Scale trains nearly my entire life.  They were something I would always make a point to set up around the tree every Christmas and from time to time, but never had the space for a dedicated layout.  When my son was little in the 90's, I purchased newer trains and cars so he could enjoy them (I let my older brother have the stuff we grew up with).

My interest resurfaced when my first grandchild was born a handful of years ago.  I thought it would be great to have him (now them!) experience the thrill of Lionel O trains I had in my youth.  I purchased the new Santa Fe Lion Chief set with Fastrack and bluetooth capabilities.  I really loved it and have since also purchased the Hogwarts set for my wife, as well as many of the relatively newer Lionel cars, mainly ones that have functions that our grandkids would enjoy, such as the searchlight, walking brakeman, chasing gondolas, aquariums, hobo jumper, etc...

I'm now interested in acquiring some of the more complex operating cars, such as the milk car with platform, and horse car with corral, accessories such as crossing gates, and also the old gang car, as well as the newer independent hand cars featuring two Disney characters.  My question is, will these items that were created before the Fastrack/bluetooth system be compatible?  Will the remote control (or phone) be able to regulate speed?  I'm more concerned that running them on new system will cause damage to either the hand/milk/corral cars' motors, or the new transformer.   I do still have an older transformer from the 90s and tubular track, but it would be great if everything would work on the Fastrack. 

Thank you for reading!
Dennis