I'll pass on the relationship discussion and chime in on the original topic.
I have been faced with this type of circumstance a couple of times, recently. The first case was the passing of my father. He was a skilled R/C aircraft modeler and a good enough pilot that about a dozen of his planes out-lived him. My mother first offered us offspring each a pick of his airplanes - although she insisted that I take a particular one (I had fabricated some parts for it). My brother and sisters selected based primarily on what space they have available for such mementos. That left the biggest and most valuable planes. Mom stored them in his shop for a while and told some of his flying buddies that they were available for a fair price - "make me an offer." Occasionally one of his flying buddies would ask her about a particular model. Over a period of years, she quietly sold them off to other good pilots. There were three that no one had any interest in (Including the DC-3 below - it was too hard to fly). I advertised and sold them via a local online classified ad service.
During the years it took to dispose of the planes, their importance evolved from "memento" to "excess stuff" and she didn't mind that the last three sold for much less than they cost. Her perspective had changed from sentimental to practical - they were in the way and she was glad to be rid of them.
I had a similar situation involving my step-daughters. They are all grown and their father had died about seven years ago. When I first began dating their mother about 5 years ago, they still clung to everything their father had owned as if he somehow still lived within these inanimate objects. Their father was a machinist, so he had a couple of machinist tool cabinets, with some very nice micrometers, dial indicators, and other gauges and precision tools. After their mother and I were married, those tool cabinets found their way into my woodshop, and they were in my way. I sensed that the girls were no longer so connected to his old stuff, so I asked if I could sell it off and give them the proceeds. They were delighted to see it go, and receive a few hundred bucks each in cash. More than once they have thanked me for "dealing with it."
My real point is that my experience is that folks seem to cling to these mementos for a while, but eventually it becomes a pragmatic issue and surviving spouses, offspring, etc. take a practical approach to it. There are plenty of accounts of spiteful spouses just dumping their departed partner's prized possessions, but I think my experiences are more common. Our surviving loved ones will want to deal with our trains in a way that honors us, even after they have grown tired of the stuff. My opinion is that we don't have to have to be concerned with what they will do, but rest secure in the trust that they will do what best honors our memory.
PS: A few details about the airplane above (in case you are interested). It had a 7-foot span and working navigation and landing lights, retractable gear, steerable tail wheel, four-cycle engines, spoilers and flaps, and all control surfaces functioned. It took nine channels to fly it. Dad loved to take it out just after sunset, so he could see the working lights and still see the plane well enough to get it safely back to earth.
Phil, I'm not a rocket scientist; they are my students.