Peter,
You bring up an issue that I am seeing happen all too often. When I down sized from a 3200 sq ft home to a 795 sq ft home eight years ago, I was fortunate that the new house had an out-building that I could move all of my rolling stock into and is adjacent to where the track was set up. Only my locomotives take up shelves in the house. But there is the real possibility that in the future I could be in a condo situation like you, and running trains will become limited to group meets at public displays or a member of a Grand Scale club that also has Gauge One track.
When I was in Japan and visiting the Yokohama Live Steamers the majority of the members only showed up with their locomotives. The club provided sets of rolling stock for the members to use. At the Diamondhead Steamup, they also have a set of rolling stock for attendees to use, to make it easier for those traveling great distances to save space in their car or if traveling by train to the event. (I left air out on purpose 'cause we know that’s not possible anymore). Many steamers are willing to share their rolling stock with others for running at other public events as well.
Where I’m going with this is that if more clubs made a couple of sets of generic rolling stock available, you wouldn’t need to waste shelf space for the stock, you would just need shelf space for the locomotives. If these same clubs could provide secure storage for members trains, to include locomotives, that would be a big help to those who have downsized as well.
Just a thought,
Scott
