SP's guard rails on the Casdade route

[markpierce]

Just turned my SP Calendar 2005 to June. It shows SD70s with an SW1500 near Frazier, high in the Cascades of Oregon. Betwizt about 15 and forty feet from the roadbed there is a steep drop off to the canyon below. What struck me was the guard rail about 2 feet on the cliff side (of about half the size the main size rail, spiked to extra-long ties.) Don't recall seeing this when I passengered on Amtrak last year. Does anybody know the extent and period of SP's use of such trackage?