If the cars have no electrical pick ups from the track they will work just fine electrically. Mechanically it depends on if the coupler systems match up.
But, if they have lights in them they get power from each of the rails just like HO or American Flyer trains do and the wheels are insulated from each other. In that case you will have no lights because in three rail both outside rails are common to return so the lamps will see no voltage drop across them, thus no light.
To make the lamps work you would need a roller pick up that will ride the center rail where the hot side, or opposite electrical potential to the outside rails lives.
The most simple way to accomplish this is to install three rail trucks.
Good luck and have fun
