Thanks to all who replied. Success so far. Steps I have taken include: Changed all activity paths so as to not go through changed portions; Deleted the interactives anywhere near the tiles on which I was working; Saved changes after each couple of deletions/additions/alterations; Ran AE and checked route paths after each session; Backed up after each session; Run a "test" activity through changes; and, Used RouteRiter TSUtils ICHK. It seems that these precautions, while tedious, have done the job. Thanks again.

Rich Brooks
Southern Ontario
"TH&B West Hamilton & Dundas in MSTS"