A bit foggy
Going back a few years I came across a kuid that spewed out fog over an area. The more fog you wanted the more little boxes you laid down. The problem was that if you wanted to get rid of the fog it was difficult to find the little box symbol in the fog. The quick way was to go into CMP and disenable the fog and then in Trainz to press the delete any missing assests.
I came across the fog in a layout of Devon from Exeter to Newton Abbot and the fog was at Longdown.
Greatnorthern