Here is my read. Basically what is going on is the two Chama Durango trains are meeting at Ignacio, and then the train from Chama meets the Farmington turn at Carbon Junction so cars can go through to Farmington. Since the dispatcher is trying to set the whole days operation up on a single train order prior to the Durango Chama train's departure from Durango, he has to figure out a way to give 497 rights to go from Carbon Junction to Durango even though 497 may not have physically seen the Durango Chama train (which probably left Durango before the Farmington turn went on duty). So you give 497 rights and a wait time. That way the Durango Chama train can highball past Carbon Junction any time prior to the wait time, and when the Farmingron turn gets back (probably long after the wait time) he can highball into Durango.
That gets it all on a single order, and the dispatcher can go on to other things for the rest of the day and the TO operators in Chama, Ignacio, Dulce, Aztec, Farmington and Durango can go back to sleep. Unless of course one of the trains falls way down and the DS has to change the meeting points.
If the DS had wanted to issue multiple orders during the day, there would be all kinds of different ways to do it. And I was thinking about the Farmington crew checking the train register at Durango, but that would only show the train had left and not that it had gotten past Carbon Junction.
JBW