I can verify that crimping with side cutters works with loose O27 track. Just hold a track pin up against the piece of track to get an idea where the notch is, then crimp there. That'll hold the pin tightly in place. The ends of the track can be reformed with a pair of needlenose or lineman's pliers that have had a hole filed into them. I just marked out the spot, chucked a needle file into my drill, and filed it out, checking it periodically against a piece of track. I guess it took me about 15 minutes. A cheap pair from a dollar store will do. Wear eye protection when you're doing this, of course. These two tools will give you nice, tight track no matter how well used it is.