For what it is worth, my take on your questions:
> I would like to know what the minimum effective track radius is
> for z scale and what minumum radius looks best for running freight
> trains. I will be running Mikado steam and F-7 locomotives.
If money and space were not a problem, a 36 inch radius would sure look
mighty prototypical. Since I have neither, and perhaps you as well, I
suggest you not drop below Marklin's snap track radius of 195mm / 7-11/16".
Since our USA group still doesn't own any metric rulers, we just 8 and 9
inches for our double track curves.
Once you get below that radius, I would suggest the cars begin to look "toy"
like, or even "Lionel" like, as they hang over the inside of the curves.
> I would
> also like to know if Micro-Train and/or Peco track is comparable in
> code and appearance to Marklin track.
MicroTrain, Peco and Marklin track all mate well (we use Peco rail joiners)
MicroTrains uses USA prototype ties/sleepers which look quite a bit different
from the Euro style Peco and Marklin track. (we use Peco because its much
cheaper, and ignore the few "rivet" counters who notice it on a US type
> Any info or advice concerning
> z scale (I'm just getting started) would be greatly appreciated.
Just three pieces of advice:
1. Clean the track surgically clean
2. Clean the wheels of the loco surgically clean (we use a N scale powered
wheel cleaner brush)
3. Clean the electrical contacts inside the loco (I call them
"scratch-and-pray" connections, since dissimilar metals are just lightly
rubbing together for the electrical "circuits" from the wheels to the motor.
Getting power pack voltage to the motor reliably may be the number one
problem in this scale.
Good track work is a close second. No point to have them move around well,
if they fall off the track due to bad track joints, binds, and gauge
problems. And don't forget to check the gauge of the wheels themselves.
MicroTrains has a nice machined (affordable) gauge to check both track and
wheels (and their couplers).
Others may have other, or differing, advice.