Arrow's Short-Lived Stand-Up Experiment

Stand-up coaster trains have existed since 1982, when Japanese manufacturer TOGO converted two of their traditional sit-down roller coasters from 1979 to the new style trains. Arrow-Huss, hoping to bring the never-before-seen concept to the US and European markets, came up with their own stand-up design. However, the results did not play out as originally planned...

EXT- Extremeroller: Worlds of Fun

In 1976, Worlds of Fun introduced their first major coaster expansion project, Screamroller. Designed and built by Arrow, it was a standard "off-the-shelf" Corkscrew model. Nonetheless, the attraction debuted with the park's new Bicentennial Square area and helped account for a 10% increase in attendance. However, with the addition of the new Arrow Custom Looping Coaster "Orient Express" in 1980, Screamroller had been beat with height, length, speed, and all new elements, making its popularity decline in favor of the superior ride.

At this point, word had spread around the industry about TOGO's development of a stand-up style train, leading to much intrigue. Likely wanting to explore the possibility of upgrading Screamroller, Worlds of Fun partnered with Arrow-Huss to develop the US's first stand-up coaster. Arrow had proposed a stand-up conversion of the original Screamroller trains, only requiring new bodies and a seating system known as "pods". Below the stand-up bodies remained the original looping coaster chassis, saving on the total conversion costs.

Worlds of Fun launched a massive marketing campaign for the new ride, now titled Extremeroller, or "EXT" for short. As it was a one-of-a-kind experience, popularity returned to it naturally. The comeback tour was short lived however, as the ride was converted back to its sit-down trains the following season. EXT remained at the park until 1988, when it was sold to Formosa WonderWorld in Taiwan.

Railblazer: Six Flags St. Louis

Six Flags St. Louis (originally Six Flags over Mid-America) opened in 1971 featuring a single coaster. River King Mine Train is an Arrow Mine Train that originally featured two tracks for added capacity. By the early 1980s, especially as the park grew, the necessity for dual tracks diminished. Six Flags and Arrow decided to convert one of the River King tracks to a stand-up coaster track.

Named "Railblazer", the ride was aimed to transform the typical family coaster into a true thrill ride. Tragedy struck on July 7, 1984, when a 46-year-old woman fell out of a car to her death. There is speculation as to whether or not she had fainted before coming out of the restraint system. However, it did not matter because Arrow had recalled the stand-up trains for investigation, and the ride never operated with them again. It was reverted back to mine train cars, and in 1987, one of the ride tracks was sold to Dollywood.

What went wrong?

Numerous problems plagued the stand-up cars from the beginning that seemed to not have been accounted for by Arrow. Since the two rides that featured the trains were designed for sit-down trains, changing into different cars completely changed the physics involved during the ride cycle.

For starters, now that riders were standing, what is known as the ride's "heartline" completely changed as well. While seated, the ride was designed to bank approximately around the chest or torso area of each rider to limit excessive forces and improve comfort while traversing intense elements. When the two rides were changed to stand-up trains, the tracks were not modified, nor the chassis of the ride vehicles. Now, the riders' chests and torsos were farther above the original heartline, meaning that any banking, turns, etc. would feel much more intense and rougher than before.

In addition to the elevated forces on the riders, the trains and tracks also felt the impact. I have seen in a few places on the internet that the stand-up trains were much heavier than the sit-down trains. To me, it seems hard to believe that this is the case, at least by a great magnitude. Arrow knew what the original track and chassis of each car could handle load-wise, and exceeding the original capacity by great amounts would be careless and unsafe.

Having some experience working with an Arrow Looping Coaster, I can say that a good chunk of the train's weight is in the fiberglass bodies. Of course, the steel frames and trucks have a lot of weight to them too, but the bodies are large, bulky, and hold all of the restraint mechanisms as well. The fiberglass bodies on Arrow's stand-up cars were much smaller. I'm assuming most of the weight rested in the steel pods for each seat, however they do not seem excessively heavy by design.

The true problem faced with these trains (in my educated opinion) was that the center of mass of each vehicle was raised significantly. Whereas before, the center of mass for the sit-down trains was much closer to the chassis and track, now it rested in the area of the seat pods. To avoid getting into a major physics lesson, in simple terms, changing the center of mass of an object affects the stability and how forces interact with said object. This principle comes into play especially when talking about rotational forces, such as torque or torsion. The forces exerted on the trains from EXT and Railblazer's track profiles were originally designed for a lower center of mass. Now the G-forces were amplified by the new train design, causing a lot of twisting forces and unforeseen stresses on the rides.

EXT's downfall allegedly came due to excessive stress and mechanical wear on its lift chain. On a lift hill, chains and chain dogs are most affective when the load is applied in perfect longitudinal tension along the chain. Any external forces or torques that put load on the chain in any other direction will wear out its pin holes much quicker and cause permanent damage. With a higher center of mass, the stand-up trains put a higher torque on the chain dogs, which derived a non-ideal chain load. Over time, had each iteration of the ride lasted longer than a single season, I'm sure that these new stresses and loads would have caused premature cracking and fatigue on the track and chassis as well, given the new dynamics at play.

Insufficient Restraints and Pods

With the unfortunate death of the passenger on Railblazer, it is quite clear that the restraint system for Arrow's stand-up trains was also a major issue. The stand-up pods featured three separate restraints at one point, a long over-the-shoulder restraint, a movable shin guard, and a lap belt. The shin guard consisted of a metal bar, covered by a cloth or vinyl wrap, that moved in sync with the lowering of the shoulder harness to keep the rider against the seat back. It seems as though the lap belt was a secondary restraint, added to stabilize the rider's torso. One thing that jumps out to me is the lack of encapsulation around the rider's body. It seems as though there is quite a bit of room between the seat back and over-the-shoulder restraint. With excessive lateral forces, a rider could theoretically slip between this gap. The restraints were not really designed to accommodate riders of different body proportions, since the shoulder harness and shin guard moved together.

In order to further secure the rider from sliding side-to-side, the pods should have wrapped around the torso more, creating a sort of shell around the rider to prevent an incident like this from ever happening. More modern stand-up trains feature the "bicycle seat" design, where the rider is better restrained within the seat frame, and there is much more adjustability for the comfort of each individual rider.

What could have changed?

1. Specific chassis design: The stand-up trains should not have been offered as an upgrade to the existing coasters, instead of a completely new train design. Of course, the purpose of these cars was to help improve and enhance existing coasters, but it's clear that the stand-up cars were not a "one size fits all" kind of product. Even if Arrow used their standard looping coaster trains as a starting point for a new chassis, critical components should have been reinforced or re-designed to handle the new ride dynamics of standing vehicles.

2. New ride track or profile: Similar to the point made above, the Corkscrew and Mine Train tracks were banked and profiled with sit-down vehicles in mind. To better improve forces and rider comfort, Arrow should have only offered this product for new builds and change the heart lining or center of rotation for ride elements. A completely new track design may have been necessary to achieve this.

3. Different restraint system and seat pods: As mentioned above, Arrow's trains offered little adjustment for different body proportions. Had the restraints been independent as far as the shoulder harness and shin guards, different body styles would fit better and more comfortably into the cars. TOGO and B&M developed universal restraints that could account for many body styles. The sides of the Arrow seat pods should have also been designed longer to further encapsulate the rider into the seat.

Aftermath

EXT and Railblazer received fairly large marketing campaigns, as Americans (and the industry in general) were not familiar with a stand-up coaster. It is safe to say that early on, they were both successful at bringing ridership back to dwindling rides. But that did not last long. Between the mechanical and safety issues at play, both rides likely would have reached an accelerated service life just a few years after conversion.

Removing the Railblazer concept completely after the accident is understandable, but Worlds of Fun did not even attempt to modify or improve their stand-up trains after the chain issues. Neither conversion is believed to last a full operating season. Within 5 years of each conversion, both of the original rides were sold and removed from their parks.

With TOGO, Intamin, and later B&M coming into the market with their own improved stand-up products, not a single park dared to trust Arrow's design after the two flawed ones. At this point in the industry, Arrow was seen as sort of a golden standard for safety and reliability, and never really had a blemish on their record. As for the trains, it is believed that Railblazer's cars were sent back to Arrow for inspection and investigation after the accident, never to be seen again. Some of EXT's cars were picked up by private collectors, and ACE (American Coaster Enthusiasts) has at least one of the trains in their collection.

External Links

WorldsofFun.org has a great article on the history of Screamroller/EXT, including a section about the controls and operation of the ride

A 2024 Video displaying the EXT pods today and the function of the restraints

News Story covering the Railblazer accident of 1984