When we did this as well, we undertook extensive consultations with shippers.
As Fred said, we didn't do a line, we actually did a circle. We did the circle around the interchange points and we determined that there would be over 80% coverage, in some instances 85%...that you, as a shipper, had alternatives to a secondary source. Going out even further would start getting into serious problems because then you're creating almost a different system. So 160 kilometres seemed to provide a good balance between providing access to more than one carrier for the greatest number of shippers.