This is one of the few cases where I actually think it's time to withdraw the locomotive. Truro is 110 years old. She's something that it would be horrible to lose due to a boiler accident, as let's face it, you couldn't replace her. She deserves the rest in a museum where her story can be told. Heck, for all we know, she may be looking forward to it.
(and yes, I do believe locomotives have souls. Think about it. The definition of life is for some thing to "eat" and "breathe" Steam engines eat coal, wood, or oil, and "breathe" air into their fireboxes.)