There are many, many ways to enjoy your trains. One way I've really increased my enjoyment is by painting trains, both for my use and for my customers.
This photos shows a set of Lionel F3's that I repainted in the famous Warbonnet paint scheme. I used Microscale decals to finish the job. These can be tough to do right with that very beautiful curve along the side, but if you make a template first, and draw it on the side using a #2 pencil, you can get this to look just like these....
I used Floquil Signal Red and Old Silver. After decals were applied, and set, I clear-coated these with Floquil gloss coat, with no flat finish added. This gave them the Postwar style luster they needed to really "pop".