Hi, John.
You are right about the markers. They were same thing as the ones on barricades. White Pass seems to have used whatever was handy. Thye train order signal at Carcross was a traffic signal! Hell, it worked.
I don't remember much about the tape but am sure it was reflective.
As to colors: "Amber" = railfan and model railroads
"Yellow" = working railroaders and rule books.
Skip Luke
Switchman (ret): Grand Canyon Railway;
Engineer (ret): Georgetown Loop RR Inc., Sumpter Valley Ry., Monticello & Sangamon Valley;
Dispatcher(ret): Illinois Central, White Pass & Yukon, Burlington Northern Ry.
Mariner, Musician, Miner