What is your favorite aspect of model railroading?

[Steamtrains]

I agree with Steve When I show off the layout to adults that have never seen a model rail road before the consensuses is usually something along the lines that it is 3D art and not just playing with toys.

When my soon-to-be daughter in law visited, she was floored when she saw the layout...My son had told her I "did" trains, so I presume she thought the ol' Lionel on a table top was "trains". She couldn't get enough, and took more pictures of it to show her father than I've ever taken...