I said "Perfect" earlier and wish now I could take that back. There are some problems with the technigues the video grapher uses. However, nothing out of the ordinary. His track on the switch side has melted down into the plastic. David, shows us how to keep the track in alignment and a heat sink isn't a bad idea. I tend to use forceps as heat sinks and that works well on curved track. Downside the weight of the forcep combined with the heat of the soldering iron, lingering to long, has a tendendy to lay the rail over. On the video I provided a link to. I referred to something I learned, which isn't new to me. I've tried this method. He uses a hot glue gun to secure the track. Not something I would use or recommend. However, it is efficient and he's right "The track isn't going anywhere". There in lies the problem how do you re-align it once it's down?
