First looping rollercoaster

The first looping rollercoasters were called Centrifugal Railways. The earliest known full-size example was built by the Manchester engineering firm Tarr & Riley in the spring of 1842. It was exhibited at the Manchester Hall of Science in March of that year before being moved to Liverpool's Royal Liver Theatre by mid-April. The first permanently installed Centrifugal Railway, and the first to be routinely used as a ride (rather than a spectacle that people only watched), was erected at Liverpool Zoological Gardens in May 1843.

Centrifugal Railways consisted of a track that descended from a launch tower, passed through a circular loop, and then climbed up to a stopping point on the opposite side (like a modern shuttle rollercoaster). They were designed in the 1830s, but it was not until a decade later that manufacturing techniques had advanced enough to make a human-scale version possible.

The earliest references to such entertainments date from the summer of 1842, with dismountable examples (made from pre-fabricated iron sections) touring the cities of Britain and Ireland. Although there are some references to people riding in the cars, and even members of the public paying to do so, these initial examples were primarily intended as spectacles – stunts to be watched by an audience rather than something the public could pay to ride. They typically appeared as part of exhibition of scientific marvels including high-power gas lamps and telegraph systems.

The example that was erected at Liverpool Zoological Gardens in the spring of 1843 seems to be the same one that had been exhibited at the Royal Liver Theater the previous year. It reportedly boasted a 40-ft (12 m) loop with 100 ft (30 m) of track descending down to it on either side. These same sources also say that the cars travelled at a totally implausible 100 mph (160 km/h), however, so these figures should be taken with a grain of salt. By the summer of 1843, the ride was definitely open to the public, with press reports mentioning the queues to get on. It remained in position until 1852, when it was blown down in a storm and rebuilt to a slightly different design.

These early looping rollercoasters were an exhilerating, but far from comfortable experience. The perfectly circular loop section meant that the riders experienced some fairly extreme g-forces on entrance and exit. Modern designs use a shape called a clothoid loop, which smoothes these transitions. Still, these high g-forces were preferable to the alternative – it was not uncommon for riders on these early rollercoasters to be pitched out of the car it if didn't pick up enough speed and stalled at the top of the loop, resulting in serious injury.