Just to show it can be done, I have assembled 2 signals from MSE components, for my 4mm narrow gauge layout, and have got as far as assembling them on a test stand . They are powered using the Peco smartswitch kit & as a servo beginner I have found this a good way in to this type of control. If I get really carried away I might even change to a GF controller but there is still some work to do yet - i.e. plant the signals on the layout!
http://www.youtube.com/watch?v=ApLz0MKmcTk