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.
Siege Engines A siege engine is a mechanical machine that is designed to hurl projectiles, typically at the walls of an enemies castle or fortifications. They are called Siege engines because their most common use was in aiding the efforts of a siege where the enemy was holed up within the walls of its fortification and waiting things out.