Thanks for the link!  The diagram/schematic at that website is what I needed.  I now see how it comes apart.  I appreciate the help.

Thanks for the note.  It was made by Bachmann in 2000.  HO Scale, Prairie 2-6-2.  Model/Stock # 51520.  I've unscrewed the top from the chassis but can't crack the code to opening up the little compartment that houses the headlamp.

How many people like me does it take to change a light bulb?  I feel stupid.  I have an HO scale Prairie 2-6-2 NY Central Steam Locomotive.  Headlamp burned out and I can't get at it.  How do I get the case opened without breaking something?  Help!