I just read an article in Pacific News (July 1992) on the Modoc Line by Greg Brown:
http://magazine.trainlife.com/prn_1992_7/

Learned some things from the article:

1) In January, 1987, after the SP/SF merger failed, the Modoc was closed as a through route:

Quote:

"Despite saving 257 miles and two crew changes between Klamath Falls and Carlin, Nev., the Modoc was closed as a through route in January 1987."

2) Rio Grande wanted access to Oregon via the Modoc as a condition of the SP/SF merger. So right after Rio Grande merged with SP, they reopened the Modoc:

Quote:

"Strongly desiring access to Oregon via the Modoc as a condition of the failed SPSF merger, Rio Grande immediately reactivated the Modoc upon merging with SP."
... "After 21 months of inactivity, the Narrow Gauge was reactivated on Oct. 13, 1988, the day SP joined the Anschutz empire."

3) Through-trains on the reopened Modoc were the EUASM [Eugene-Alton & Southern (East St. Louis, Ill.) Manifest] and the ASEUM.

4) Starting in the late 80's, Holly Sugar and Spreckels Sugar started growing sugar beets in the Klamath Basin. The SP ran beet gons on the Modoc on the Copic Local and Staley Turn for the new traffic.