No the 2 rails are not isolated from each other. People have run 3 rail DC on Marklin track, but I'm not sure why you would try and run 2 rail DC on Marklin 3 rail track. You might as well just buy some 2 rail track!

I don't know about K-track, but for C-track it's just a matter of cutting two "bridges" on the underside of the track. Hardly not impossible. Isn't it quite the opposite (hard on K and or M, but easy on C)? Am I missing something?

I am in agreement with Chris that ETE recommends K-track be used for its modules. It is very easy to isolate the outer rails on C-track. The problem with all track forms are turn-outs (points) and cross-overs.

It is not easy to run 3-rail DC on Maerklin track as the outer rails are not isolated from each other. It is easy to operate Maerklin on 3-rail DC track! In fact one can operate a TRIX Express locomotive and a Maerklin locomotive together under their own analogue controllers!

My suggestion is if you want to operate DC use 2- track, if you want to operate Maerklin AC use either M-,K- or C- depending on your preferences. TRIX Express/Twin track is 3-rail however differs from Marklin in rail profile height and also each rail is isolated.

I have a travelling TRIX Express layout for train-shows and just added a tunnel module with Bemo HOm track. The two systems are not compatible but the HOm track is electrically isolated from the TRIX system and adds an interesting dimension to the layout. I will be adding a narrow gauge system to my permanent layout for that very reason.

If you want to include a DC loop and/or an HOm loop on your layout you can easily do that. Install the track system you want and just have them electrically separated and use different transformers/controllers. If you decide to use the Tillig HO/HOm track you can "kill two birds with one stone." Just remember to keep that system isolated from your Maerklin AC layout.

Let us know how you progress.

Steven,

Thanks for the note. Yes, the new TRIX C-track is designed for 2-rail DC. One has to watch the rail profile height with this track as it is Code 83 (2.1 mm). If you are using Code 100 you will need an adapter piece to connect the DC track systems. You may also need to pay attention to your wheel flanges! For everyones information here are some useful data:

Maerklin C-track is 2.3 mm (0.090" or Code 90)
TRIX C-track is 2.1 mm (0.083" or Code 83)
TRIX International is 2.7 mm (0.106" or ~Code 110)
TRIX Express is 3.3 mm (0.129" or ~Code 124)

Maerklin M-track is 2.5 mm (~0.100" or Code 100)
Maerklin K-track is 2.54 mm (0.100" or Code 100)

Ok, I stand corrected....... I was basing my comment on 2100 series track, admitedly, which appears to be not isolated.

Thanks guys! I have my reasons (AKA lack of space and owning 90% Makrlin, but some DC as well) to run DC on Marklin K track from time to time.

So what I'm taking out of this is its no problem provided you use different rail joiners. But I'm a bit fuzzy on turnouts though- will they work? (the section in question is only 1 simple siding.)

In regards to K track:

wide radius (22715/22716/2275/2257) turnouts/double slip/crossover rails are isolated from each other.

The standard turnouts (2265/2266) rails are joined - They can be isolated easy enough by cutting the two links near the end of the branch on the underside.

I am not sure about standard double slip (2260), curved turnouts (2268/2269) and crossovers (2258/2259) as I did not use those.

A copy of the ETE module specification (courtesy of ETE) can be found to download in post 1 of this thread: https://www.marklin-users.net/forum/posts/t35299-Marklin-Club-UK---Modules-for-Modular-Display-Layouts---Help-with-Signalling