Feeling bored in the Train - talk to a RailFan. You'll WISH the train gets late.

If you open the given link, you will understand. It's basically the layout of a particular route drawn on an image imported from google map.
Updating a full route in one shot in quite cumbersome, so we do it segment-wise and save it the different versions in increasing chronological order.
For example, a route goes from A to C via B. I modified the drawing from A to B in one day, and saved it in say p-th version. Next time, I will open the route again, and modify the rest, say from...
more...

B to C, and again save it, and it will be the (p+1)-th version. Or if I have to add a new station in a given route, then also I have to modify the route and save it in a new version.
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Only Atlas Monitors have the authority to modify a track version or a track type.