train whistle doorbell - Classic Toy Trains Magazine

Here's an idea. After you solve the voltage issue why not mount a small mantel, like the ones used for decorative purposes, where your current bell is located with just enough track for an old steamer and tender. Wire the tender directly with a disconnect of some sort so you can take it down if you need to in the future, painting, dusting whatever. The steamer can be totally disfuntional it is only there for appearance.
In essence you would have a functional piece of art. [:D]