distance
How far this transporter has travelled in this replication, in the network's own length units, including the part of a traversal still under way.
The distance is the ground actually covered, which is not always the length of the zones entered: a transporter that backs out of a spur is credited its own length against the way out (see physicalLength), and it does not travel the distance that credit pays for. The in-progress term is linear in elapsed time, which is exact -- a traversal runs at one velocity from the moment it is scheduled.