I hope this can be a simple project; I'm not an EE guy.
I want to connect the output of a MTH Z750 transformer (18 VAC, 75 watts) 
to a project box containing three rheostats, each with a control knob capable of delivering 0 to 18 VAC output as track power to lock-ons at three separate trolley lines. Do-able? Feasible? If so, what value rheostats should be installed?
I've read web pages that suggest a potentiometer can be used instead of a rheostat. If so, what value "pot' would be appropriate?
A recommended source for the devices would be helpful. I couldn't find products at the websites for Radio Shack or Del City Electronics.
FYI, the three trolley lines are rather short -- approx. eight to ten feet long -- with bump-n-go devices placed on the rails, as:
* Lionel "Brill" Christmas trolley
* MTH Santa Handcar
* Industrial Rail two-truck trolley.
Each device has its own "favorite voltage" for maintaining speed, which is why I need want to provide the "just right" voltage to each trolley line (not the same voltage to all three lines.) The speed must be controlled so as not to SMACK! the bumpers at the ends of each line too hard and cause a derailment, yet activate the onboard reversing feature.
I considered installing three MTH ZDC1 transformers (20 watts) for DC power to each trolley line, since all three devices have DC can motors inside. However, that seems to be overkill, albeit an elegant solution.
Responses can be sent by e-mail to: mottlerm@gmail.com.
With appreciation,
Mike Mottler (ritrainguy)
501-327-8747
