Of course, you could just use a Lionel R2LC and trigger it with the smoke control triac,
Awww, where's the fun in that?
One plus to the custom solution, besides the choice of outputs, is that you can easily program an arbitrarily complex response into your receiver. Like in this application, a single press of AUX1 keeps the relay engaged for the 4 seconds necessary to initiate the cycle. But it could be more complex - you could, for example, roll your own equivalent to a hot box reefer with sequenced lights, smoke, sound, etc.