I agree that Con_rail's system made moresense...but the way CSXT is supposedly gonna do it, is going to be a bit more than just the 1st 2 letters of origin and destination cities and the date of origin.
What I heard is that it will be 1st 3 letters of origin and destination cities, a "section #", then the 2 numbers for the date. For example Selkirk to Buffalo on October 4th would be SELBUF-01-04, and if another section ran on same day it would be SELBUF-02-04.
Conrail would have been SEBU-04 and if a 2nd section was needed, that 2nd section would have been SEBU-04-B
The latter of course seems simpler.