Adding a smoke unit on-off switch for American Flyer steamers

I am considering adding a small slide switch in the cab of my Flyer 302 Atlantic so I can turn on/off the smoke. I understand where to wire it in the circuit, but am unsure of the required amp rating for the switch. Does anyone know what to use?

It does not matter, any switch should work. The Gilbert smoke unit draws less than .5A.

Thank you.