Train numbers 17 & 18 once denoted the Columbian, but by the time of this timetable they had lost the name, only operated as far as Marmarth, ND, and were merged with the Pioneer Limited east of Minneapolis.
How did railroads come up with train numbers? The Pioneer Limited was trains 1 & 4. The Copper Country Limited was 2 & 9; I don’t see any sign of train 3. The Morning Hiawatha was 5 & 6, but the Afternoon Hiawatha was 100 and 101.
The 1940 timetable had 106 numbered tables. Not counting freight-only tables or connections with other railroads, this one had only 34–and five of those, including from Three Forks to Gallatin Gateway, were for buses.