The last train show I went to, they used one of those smaller portable DVD players mounted in a way that only the screen showed. The rest was mounted on a bracket that went below the scenery level.
What made it really slick is that the baseof the screen hid the rest of the player.
Some of the newer portable DVD's are a lot thinner than the one I saw and would look a lot more in proportion.
Post a pic when you get setup and maybe give us a short "How I did it"