Mixed trains 5 and 6 and scheduled freight No. 10 all had timetable meets with each other at Dolores. No. 6 would normally have right over No. 5 ("Northward trains have right over Southward trains of equal or inferiour class" - back in the days before all railroads were standardized "Eastward-Westward"), and the two would normally meet before 1 PM, last one out of Dolores at 1:05 PM, IIRC.
No. 5 must have been running 30 minutes or so late this particular August day.
Thanks for sharing, John!