What Carl said. Fastrack switches only have a small DC motor to activate the switch, they draw less than 100ma maximum during the switch operation, even less at other times. Since I run command pretty exclusively, I run the switches from track power to minimize the wiring issues. I use the command Fastrack switches, that way I don't really have to wire extra control wires either, just plug them in and go.
Do you run DCS as well as Legacy on your layout ? Reason I ask is I always understood that when running DCS it is recommended to power the Fastrack switches with accessory/external power and not track power ?