My favorite 18xx game for six players is two games of 1846 with three players each.
Great. I'm a newbie and was confused. One can certainly move on railroads in the various phases but its not considered Rail Movement.
Right. Railroads can function as tracks (e.g., something that eliminates the terrain cost as long as you march along them) even if you haven't converted them to your side's gauge. This is not rail movement.