An amulet of life saving is probably the most useful amulet you'll ever find, while upon taking fatal damage you return to maximum health, but destroying the amulet. They are especially useful when using the "Forge Legendary Armor" service at a Smith Vendor, as you can combine the life saving attribute with your armor to gain its effects, and equip a secondary amulet of unchanging, reflection, or any other useful combat neck.
When worn whilst drinking a Potion of Enlightenment it will state "your life will be saved" as an attribute.
It will not help against the train
There may a bug where the armor will not be destroyed. This may be fixed as of version 1.2 .