Yes the CS3 can easily run 2 rail DCC (as well as 3 rail DCC). Maerklin does have the Trix 2 rail series that uses the same controllers.

I don't know if mixing the two systems in a layout poses any issues that one has to be aware of. But others might chime in here.

Hi Newbie (another first name perhaps?)
A warm welcome in this forum.

Yes the CS3 can operate 2 rails and 3 rails network in 3 different protocols: Motorola, DCC, MFX.
Mixing Märklin 3 rails with 2 rails locos and cars will require one of the following:
- 2 different, non-connected parts of your layout
- adapt either all your 2 rails stuff into 3 rails or vice-versa.
- instead of purchasing Märklin, you purchase the 2 rails equivalent by TRIX: absolute same locos and cars but adapted to 2 rails

The other adaptation is for sensors:
- in 3 rails, this is done by using 60881 (S88)
- in 2 rails, this is done by using 60882 which is a current-sensing device (2 isoled groups of 8 sensors)

In 2 rails, because of the current-sensing approach, for precise detection, graphite paint used on isolated wheel-sets will allow the precise detection of all cars even when no lighting, etc. Recommended resistor is around 5 kOhm per axle.

Cheers
Jean

Yes it’s possible to use 2 rail and 2 rail with stud contact with same digital system. How ever i recommended an system that have possible to adjust power setting to the track. For H0 i recommended 16 V which are standard in this scale.