Siding is Pierce, it is at the top of the hill between McCloud and Mt. Shasta. Was used in the good years to reassemble trains brought up out of McCloud in sections due to the short length of the Signal Butte switchback tail track before it was lengthened in 1975. By the late 1980s the railroad used it primarily for car storage, the covered hoppers could be cars stored temporarily for GE Capital or somebody else, or empty cars held until Dicalite could use them, or covered hoppers going to or from the shop for repairs. Link to the siding location in Google Maps:

[goo.gl]

Jeff Moore
Elko, NV