The 1938 D&RGW report on the Branch lines (400+ pages) is still available from the Colorado RR Mueseum and has some data on the section organization. Typically section "Headquarters" as the report terms them were about 20 miles apart on most lines, but this varied. An average work force (could again vary depending on the situation) listed in this 1938 report consisted of 1 foreman and 3 section men assigned to their respective section.
The Silverton branch for instance listed Section HQ's at Durango (shared responsibility for 4.5 miles Farmington Branch and 6.5 miles of mainline to Chama), Hermosa, Cascade, and Silverton. The Farmington Branch listed Durango (shared with Silverton), Bondad, and Aztec. The report only covers the "branch" lines so no data is presented for the mainline between Durango and Alamosa.