While most of us are limited to the visible spectrum, people with a condition called aphakia possess ultraviolet vision. Aphakia is the lack of a lens, due to surgical removal for cataracts or congenital defects.
A railroad lantern and a railroad lamp are two different things. Lanterns were designed to be portable (i.e. carried) and were basically globes surrounded by a metal frame with a fuel source. When you think of a railroad worker swinging a signal, think lantern.
Railroad Board is a smooth, thin, bristol-type board, colored on both sides, that is used for signs, posters, mailing cards, tickets, tags, and so forth. Each sheet is coated on both sides with bright colors or white. Thicknesses are 4 ply (0.014) and 6 ply (0.020).