When I was very small I was fixated on anything to do with trains and Thomas the Tank Engine; and one evening what I now know to the TV movie "Runaway!" came on, about a runaway train careering down the mountains from a ski resort, and the attempts to stop it crashing at the end of the line. Because I was so 'good' and silent my parents let me stay up past bedtime to watch it all, probably thinking I was just fascinated by the trains, and to an extent I no doubt was, but that was also probably the first time I experienced such a sustained period of tension and suspense, which was scary to a little mind!