I apologize upfront for my ignorance.  I am trying to find out "what I have".  My nephew's boyhood HO train set was just given to me to see if I could establish its origins and to get it in operating mode so it can possibly be given to his sons.   The loco has the Bachmann name and 'Hong Kong' on the bottom.  The Santa Fe loco is red and silver with the number '307'.   The other cars are:  brown CN box car #CN529384.  The name PENCO is molded into the bottom of that car.  Red flat bed car #ATSF90850 mfd. by 'AHM? (Taiwan).  Shiny blue box car 'THE ROCK' #57028 mfd. by Bachmann.  Orange/Silver 'Excess Height Car' Rio Grande D&RGW #60649 mfd. by Bachmann.  Red Tanker H.P.C.X.#3845.  Yellow Union Pacific #518125.  Red/yellow Santa Fe caboose ATSF #3851.   Can anyone here identify or tell me how to identify.  Also, what recommendations would anyone have as to how to test and clean?  Thanks in advance for any and all your assistance.  Tom