These Great Northern timetables were issued in May of 1964 and 1965. The pattern seems to be that GN issued its summer timetables on the Sunday in May prior to Memorial Day weekend.
There are very few changes between these timetables and the ones from 1963. Perhaps the biggest changes are that 30 minutes was added to the Empire Builder‘s schedule and an hour added to the Western Star‘s westbound schedule. All of the time added to the Builder and most added to the Star was east of Shelby, Montana.