When I drag a square selection and then alt-click a road network, everything is duplicated in place as expected. I can then move and rotate the pasted selected network as expected, however when I am finished, I notice that the pillars supporting raised sections of the network are now treated as completely separate objects (ie they are not linked to their respective nodes any longer). While I can sort-of work around this by simply deleting the pillars, it seems to me as if this behaviour is not intended.

Either I am missing something, or this seems a bit like it may be a bug to me...