A startling video shows the moment a section of rollercoaster track crumbled away mid-ride forcing the passenger cart to grind to a halt. The eyewitness footage was shot on Dreamland Margate’s Scenic Railway ride minutes before staff rushed to the aid of passengers. A Dutch theme park enthusiast recorded the incident while sitting on the front row of the UK’s oldest rollercoaster which, since then, has been listed as closed. Posted on YouTube account Coasters ‘n’ Cocktails, it first shows the ride running normally, before highlighting a small piece of what appears to be wood on the tracks. Aft…