VO: This is the big one! It's one of the fastest and tallest roller coasters in Europe. At 67 meters high it dominates Blackpool's skyline. And every year over 1 million people clamber aboard this monster to experience the ultimate thrill. But, before the theme park opens its doors, the trains and track have to be tested.
VO: First, engineers harness themselves to different sections of the ride and have a good look around. They're checking for things like loose bolts, rust, contamination from grease or oil and any foreign objects. Stuff that could get in the way of the train as it hurtles around the track at 120 kilometers per hour.
VO: When the engineers give the track the all-clear, sandbags are strapped into the train to simulate passengers and it gets sent around the track once at full speed.
VO: There are 4 sets of 3 wheels that hold each car onto the track and they must all be inspected along with the rest of the undercarriage.
TESTER: "We got the main running wheels. We got the side friction wheels and the [ruck] stop wheels. Because all we do with these we just turn them, make sure there's no cuts in them and just make sure they're in good condition. These are the main brake fins that stop the train. We got to make sure that these brake fins, there's no contamination in them at all. And then mainly we check for all axle bolts, axle pins, lap bar bolts, lap bar mechanisms. Make sure everything's all in place."
VO: In high season this ride gets stopped and checked 3 times a day. The biggest danger is if one of the coaches comes to a sudden halt and the following coach hurtles around the corner and smashes into it. So they have to test the emergency breaks. They simulate a stricken coach here. And send a second coach on its way. It should automatically sense there's a blockage on the line and come to a halt.