Saw this while browsing a hobby site. Might be good for someone? http://www.sciplus.com/recommend.cfm/recommendid/14513
“This Velleman® steam-engine sound generator kit comes with circuit board, components, battery connectors, speaker and instruction sheet. You add solder, a soldering iron and a 9V battery. Volume and (implied) speed are adjustable and there’s a horn button, so it’ll go both choo-choo and whoo-whoo. Great for train hobbyists or people bored with their doorbell.”