A mountain coaster is not a “roller coaster”

The case of an injury on the Branson Coaster

Like many reports covered in the RRRR database, multiple media reports used imprecise terminology that has real implications for potential misunderstanding of hazards to the public. While it is understandable that a reporter may not know the difference when beginning to collect information for a report, it is irresponsible to be cavalier about terminology in the published version. Any hazards that may be implicated in this case have no relevance to “roller coasters”.

On 20 June 2021, an 11-year-old patron at The Branson Coaster (Missouri USA) described as having “15% vision” in only one eye was injured after falling and being trapped for over an hour beneath a “roller coaster” that had stopped and restarted. In subsequent coverage reproducing a social media post by the emergency responders, it was clearer that this was a “mountain coaster” and not a “roller coaster”. The difference is highly relevant to this case.

A “roller coaster” will typically have seating for multiple occupants per vehicle, enabling guests who need guidance of any kind to have companions with them. When a ride stops, some riders unfamiliar with the ride may misunderstand the situation as the end of a ride or a failure needing them to evacuate in place. A “roller coaster” may have an intentional pause mid-cycle, to enhance the thrill, or automation or operator input may cause a train to stop in response to a fault requiring correction and possible evacuation. During these pauses, some patrons may reposition in ways that can cause injuries if movement resumes, especially as an abrupt launch. However, this occurrence and freedom of movement is mitigated by the use of restraint devices appropriate to the ride’s acceleration profile and interlocked with the ride control system if necessary. Riders’ improvised actions are also mitigated by the presence of ride attendants or use of public address messages advising the guests of appropriate actions and measures being taken to restart or evacuate.

As illustrated in the tourism site photo below, a “mountain coaster” is essentially a sled on a rail that descends a slope under gravity, undulating and curving to follow terrain. Sleds may have one or two occupants, in this case one. Individual sleds have manual brakes that must be operated by the rider in the event the sled is closing on the sled that descended on the rail before them. During the descent, a sled may have insufficient momentum to continue to the end of the path. Curves and hills expend some momentum, and a rider may have activated the brakes to slow to a comfortable speed, and a lighter weight of occupant will have less momentum to begin with. If the rider exits from the sled and is no longer applying any braking, the sled may begin to move, which may further destabilize the position of the rider in an area not designed for unloading. If the track at that point is above the terrain, the rider may fall.

Mountain coaster screenshot from ExploreBranson.com

In patron directed rides with single occupants, some vision is often involved. While there is no steering as with bumper cars or go karts, the mountain coaster rider must brake to avoid colliding with the previous sled. It is unclear what accommodation is made for blind guests to know that they need to brake to avoid colliding with the previous sled – perhaps their sled is not dispatched until the previous sled has reached the unload area. Riders must also be prepared to remain in the sled until they are at a safe unloading location. This is easily achieved if the descent is uninterrupted, but possibly problematic if the sled does lose momentum and stop. It seems quite possible to make the ride safe for a properly instructed blind guest, but not clear that this happened in this case.

In this specific attraction (point of view video here), the mountain coaster has some unusual features, including separate segments, with a fast downhill portion, a level segment, a lift, a gentler slide downhill, another lift, and another downhill slide.

According to Screamscape, riders 16 or older were allowed to ride with others (and has not been reported whether the other rider has a minimum or maximum size), as long as a rider 16 or older operated the brakes, but single riders for those aged 9 to 15. (This is contrary to many attractions, that require companions under a certain age or its corresponding size, allowing single riders only above that age.) The venue required riders to have the ability to operate both brake levers, so it is clear some manual braking is required. The family reportedly requested to have the injured child and his 13-year-old brother ride together, and with double-occupancy sleds available, the venue could have accepted the family’s determination that the rider with limited vision did not “have the ability to operate both brakes” as long as the two did not exceed the sled’s capacity. (It is important to differentiate this from a venue saying “madam, you appear to have some sort of disability, so you may not ride without a companion”.)

The failure of the restraint devices to contain the rider was also remarked on by Screamscape. The image shows a shoulder belt which presumably is connected to a lap belt as in an automobile. The restraint system should remain locked until arriving at the actual unload station. Again, a patron who believes they are supposed to exit may find a way to self-extract. This may be possible for a slender rider with a lot of agility to go along with their motivation.

The seriously injured patron was rescued by emergency responders and airlifted to hospital for treatment of fractured arms, legs, skin grafts, and other treatments.

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About Kathryn Woodcock

Dr. Kathryn Woodcock is Professor at Toronto Metropolitan University, teaching, researching, and consulting in the area of human factors engineering / ergonomics particularly applied to amusement rides and attractions (https://thrilllab.blog.ryerson.ca), and to broader occupational and public safety issues of performance, error, investigation and inspection, and to disability and accessibility.