Hello,
Yes...
I have built the train 6 Wide and upstairs is is only 4 wide...
well but it is Verg Long and lang Curves (3,80m) for That I have material but no place -it´s too big...
SO it must drive on normal Curves...
But if it is 8 WIde,it needs very much Place between rails,then I couldn`t plane more Rails
Here my rails in August and my Long Curves...
http://www.youtube.com/watch?v=uwKxHMnwV6A
more:
http://www.youtube.com/legogroserzugsammler
Best Regards.