An Up-and-Down Career: Roller Coaster Engineer

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The Original Structural Analysis in the Cloud?

Last week I was chatting to my daughter about my blog.

“Your articles are OK,” she said.  “But why don’t you write something that would appeal to someone my age, a 20-something?”

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“Like what?” I asked.  “What aspect of structural engineering might interest a 20-something?”

“How about Roller Coaster Tycoon?” she suggested.

It seems that Roller Coaster Tycoon (originally introduced by MicroProse 16 years ago last month) was one of the iconic video games of my kids’ generation.  It was an important part of growing up for just about all of their friends.  I was somewhat aware of the game, having bought a version or two for Christmas presents in the past, but I didn’t realize that the purpose of the game was to design, construct, and maintain the structures of roller coasters and other amusement park attractions.  My daughter told me it was like structural analysis software for kids — so I suppose the upcoming online/multi-player version will steal a little of CloudCalc’s thunder by offering its own version of Structural Analysis in the Cloud.

Researching Roller Coaster Tycoon I became impressed by how much it actually does seem to simulate the job of an engineer.  In addition to replicating the design and construction process, it also rewards the player for delivering in the areas of economy and safety.  (How do they do the latter?  To quote Roller Coaster Tycoon’s Wikipedia page: “Ride crashes that kill guests will drastically decrease the park rating, which is detrimental to your objective.”)  Young engineers of the future learn early on that whereas anybody can design a structure cheaply or unsafely — only an engineer can efficiently balance those two goals to get maximum safety at minimum cost.

I started wondering how many of today’s 20-somethings were inspired to become engineers due to early exposure to Roller Coaster Tycoon.  While trying to research that I discovered something else – there is a thriving engineering discipline of which I had never been aware: Roller Coaster Engineering, which while primarily being a branch of structural engineering, also mixes in large doses of the disciplines of mechanical engineering, instrumentation and control, and physics.  And even though I got nowhere in my attempt to pinpoint how many structural engineers were inspired by Roller Coaster Tycoon, on-line evidence clearly indicates that a large part of the roller coaster engineering community gained their love for their chosen profession directly from that game.

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Formula Rossa, in Ferrari World in Abu Dhabi – the World’s Fastest Coaster at 149mph (ride Formula Rossa here: https://www.youtube.com/watch?v=khRTNdEgZqg)

Today’s roller coasters are descendants of ice mountains originally built during 17th century Russian winters, down which the local nobility would hurtle headlong in sleds for their amusement.  This activity was so entertaining that the French adopted it during the early 1800s, but having a lot less ice and cold, were forced to make mechanical versions, with carts hurtling down sloped tracks.

The concept spread.  In the United States, the Mauch Chunk Switchback Railway, a gravity driven railroad used for transporting coal down from a mountain top mine, was built in 1827 in Summit Hill, Pennsylvania.  The 5-mile trip down the mountain was so fast and bumpy, that soon the train became more profitable as an exciting amusement ride for the upper crust Pennsylvanians than as a coal transport.

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United States’ First Roller Coaster – the Mauch Chunk Switchback Railway

This actual working train inspired the first “modern” roller coasters: in 1881, LaMarcus Adna Thompson, a preacher from Ohio, built the first roller coaster in the United States designed for amusement purposes: a simulated version of the Switchback Railway in Coney Island, New York.  This became not only the first of many roller coasters in Coney Island, but led to many more in the United States and throughout the world.

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Pre-Computer Version of Roller Coaster Tycoon?

Today there are nearly 3,000 operating roller coasters in the world, built by approximately 100 firms specializing in this narrow area of engineering.  Some of the better known firms throughout the years are/were Arrow Development/Arrow Dynamics (original developer of many of the Disney properties’ early attractions), Bolliger & Mabillard (designers of nearly 100 coasters over the last two decades), Custom Coasters International (the world’s most prolific designer of wooden roller coasters), Intamin (known for pushing the envelope on speed, height, and acceleration), and Vekoma (responsible for nearly 10% of the world’s current roster of roller coasters).

What are the challenges a roller coaster engineer has to solve?  The main one for a thrill ride such as this would be to create a sense of great danger for the riders while in reality assuring their total safety.  Which means finding ways to structurally resist some unusual loads…

Roller coasters are known for their extreme accelerations, which equate to excitement on the part of the riders, but likewise equate to outsized loads on the structure.  Of course there are limits to these accelerations. ASTM Standard F2291-14 “Standard Practice for Design of Amusement Rides and Devices” limits acceleration vs duration, relative to the human axes, in order to prevent brain injury to the riders:

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Stay below these g-levels to avoid killing guests,
as that might drastically decrease your park rating

Here we see that a roller coaster car may momentarily experience accelerations of up to 6g – which means that the structure supporting it simultaneously would need to handle 6 times the weight of the car and the human cargo.  (In reality the world’s record for sustained acceleration is held by the Dodonpa coaster in the Fuji-Q Highland Amusement Park, in Japan: zero to 107 mph in 1.8 seconds, which corresponds to an acceleration of just above 2.7g, nearly what an astronaut experiences during liftoff.  Ride Dodonpa here: https://www.youtube.com/watch?v=ZqPykRYD5Bw )

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Dodonpa: Top Acceleration Among all Roller Coasters (2.7g sustained, 4.5g peak)

As though these high accelerations aren’t difficult enough to deal with, the nature of a thrill ride is to vary the experience – changing the rate of acceleration (g-load), plus very importantly, the direction of application.  This means different sections of the track have to be designed for downward loads, upward loads, frontward loads, backward loads, or lateral loads, or simultaneous combinations of all of the above.

As the car/train moves along the track, the magnitude and direction of the structural load is always changing, as the car switches direction and changes speed.  This creates a dynamic loading, which must be evaluated for possible further amplification, due to the dynamic characteristics of the structure itself.

Additional loads on the roller coaster are similar to those acting on more traditional structures, as mega-coasters have pushed elevations to over 400 feet.  At this height, wind loadings may govern the design, or even seismic loading — mega-coasters are becoming very popular in earthquake-prone Japan.  (The world’s tallest coaster, at 456 feet with a 418-foot drop, is the Kingda Ka at Six Flags Great Adventure in New Jersey.  Ride Kingda Ka here: https://www.youtube.com/watch?v=HN8nv4tVFuA)

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Kingda Ka:  What goes up, must come down –
World’s Tallest Roller Coaster, World’s Deepest Drop

Once the loads are calculated, the engineer’s work becomes even more interesting, due to the non-standard type of structural components that must be evaluated.  Whereas commercial buildings largely consist of a familiar array columns, beams, braces, trusses, etc., resisting the various roller coaster loads are bent and twisted steel tubes, loops, inversions, etc. – components which one rarely had the opportunity to analyze in strength of materials class.

Interested in getting into this area of engineering?  I suspect it takes a strong combination of determination and luck, as well as a certain amount of notoriety in the Roller Tycoon on-line chat rooms.  However it can’t hurt to get some practice before trying to break in with one of those 100 roller coaster engineering firms – so here are a couple of useful resources.

  • Entertainment Engineering, a book by John W. Wesner, http://www.amazon.com/Entertainment-Engineering-John-W-Wesner/dp/1304351831 has a chapter on roller coaster design, which includes a number of engineering problems to solve.
  • No Limits Roller Coaster Simulation Software http://www.nolimitscoaster.com/.  This software is Roller Coaster Tycoon on steroids – it provides an accurate, real time simulation of any roller coaster, both from a visual and a physics point of view (the latter by providing continual calculations of speeds, accelerations, and potential and kinetic energies).  This software is used by many of the roller coaster engineering firms to first help design, and then showcase their top coasters.

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Is it real, or is it No Limits?  Simulation at its Best

Hey all you 20-somethings – this one was for you!  (Special thanks to Marika for suggesting the topic.)

Designing a roller coaster?  To help avoid “ride crashes that kill guests and drastically decrease the park rating, which would be detrimental to your objective”, use CloudCalc, the scalable, collaborative, cloud-based engineering software.  www.cloudcalc.com – Structural Analysis in the Cloud.

By Tom Van Laan

Copyright © CloudCalc, Inc. 2015

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