Here's another illustration of what Photoshop can do.
I took this photo of a set of F3 diesels on a trestle several years ago on Gayle Rotsching's layout. The trestle itself is fantastic, but there was no scenery behind the train, just a dark wall and some distant scenery.
I spent a few minutes building a "path" (an electronic outline) around the locomotives to use to cut out the background. Then I looked through my image library for a suitable stone wall to use as a background. I had to find something with the light coming from the left, in order to match the lighting angles between the locomotives and the background. This is the result.
However, we have a problem. Because these locomotives were stopped on the trestle for the photo, there was no power on the track. We've got no headlights. That's not legal!
OK...we're legal now. The headlight and Mars light are on. Both lights were added in Photoshop, not by turning the power on to the track.
Adobe Photoshop...it's a wonderful thing. 
