Hi,
Switches and crossovers use a different type of guardrail (mainly spacing) than bridge guard rails. These two items with the same name are for different purposes.
As for Lobato and Cascade, they are the tallest bridges on the C&TS and a car falling from either would be catastrophic. Very difficult to get the equipment back up to the tracks.
All the others excepting the Rio Chama are relatively lower and (in the care of the old Hwy 17 bridge) easy to access with heavy equipment that is not rail mounted.
The Rio Chama bridge has a "cage" that encloses a derailed train. It is difficult to work inside a "cage " to put the equipment back on the track, but not impossible.
Also notice where guardrails are used when not on bridges or switches. They are used in places like ledges and sharp turns. Places where the cost of derailment would be very, very high. and accessability would be difficult.
Just some observations.
Doug vV