In general, I'm in the 'if it hasn't appreciated much in the first year, dump it' camp. However, with the LR train there's a separate issue. Target clearanced these (again) several months ago for $70. I do think that messes with predictions a bit for this set, as there are lots of flippers out there who will take their $15 profit and move on. So I give the train another six months to show me what it can do. As for the others, if I had them, I'd sell them.
Edit: True story. I bought lots of 10144 Sandcrawlers back in the day for $100 each. Thought I'd get $200 for 'em after a year. But after 12 months the price was more like $160. Awful appreciation off a $140 MSRP base. But I love jawas and I love sandcrawlers, so I held for another 2 years and sold at $350 - $400. It was worth the wait.