Over 40 years of knowledge gathered from all the engineers that have joined Birket throughout the years.
We’ve gathered the most frequently asked questions and have answered them for young engineers working on projects or planning their careers.
Your biggest challenges are:
- intense competition – lots of engineering students want to be theme park attraction engineers, and
- the growth in the themed entertainment industry is outside of the United States for the foreseeable future.
These are some questions we might ask of you:
- Have you had opportunities for practical application of your technical knowledge, even if it was at home or before college?
- What engineering co-op/intern experience have you had?
- What electrical and electronics classes have you had?
- Were you a good student?
- Did you go to engineering school because you really like engineering, or because you thought it was a path to a good job?
- What software experience have you had? Is your interest more in software or hardware design?
- Ever encountered a PLC or have any idea what you’d do with one?
- Have you traveled outside of the United States?
- Do you speak any foreign languages?
- What would you think about working outside of the U.S.?
You should become a member of the TEA NextGen group and attend TEA events as a way to get to know people in the industry. The members are students who are aggressive about finding work in the theme park business. If you are not a member, you will be in line behind those who are. You may also wish to attend IAAPA. It is in Orlando every November and in a major Asian city every June or July. Generally the younger engineers now come to us by building relationships with our existing employees through the TEA functions and sometimes by meeting us at IAAPA. If we then offer them a summer intern position that works out well, the door often opens to a full time offer.
Companies like ours that support theme parks will always be working on one or two new attractions at an existing theme park in the U.S., but the bigger volume of our work is overseas, particularly in Asia, building whole new theme parks. That figures into our hiring decisions. There are plenty of graduating engineers in countries like China. To be competitive delivering theme park attractions in China, we have to hire local Chinese engineers over U.S. engineers who must be relocated overseas at great expense. If we don’t hire in China, our U.S. business will struggle to be competitive, which prevents us from growing our business and doesn’t help anyone. Our overseas offices are growing faster than our U.S. office. If we keep our overseas offices growing, we believe that we can also grow our U.S. office, but perhaps more to support product development than the steady level of new attraction development in the U.S.
Companies in the themed entertainment business generally like to hire people who demonstrate a real passion for the theme park business. That is because this can be difficult work. After a few months away from your family in a country that serves food you may not like, working to commission a ride or show for an unappreciative customer, on the the third shift, on a muddy and dirty construction site – you might decide to give up if you don’t really have a passion for this kind of work.
The usual – good grades and some experience in this market would help. A lot will depend on the market demand when you graduate.
It is a definite plus that you have a real interest in theme parks, but it will help more if you have some connection to the business so that a prospective employer will have someone to call who knows you and can recommend you. We, like most employers will naturally take a “known” over an “unknown” candidate. We are successful most of the time at hiring individuals with whom we either have direct experience, or at least we know someone who knows them. The direct experience often comes from working on a project together.
For example, if you have a role on a project working for someone else, and we get to work along side of you, or know people who work with you and say good things. Then when we are looking, we think, “hey, remember that guy that did a good job of xyz, he’d be good at this, maybe we can get him.” That is the way it usually happens. You don’t even have to be working as an engineer – just out there were others can see you somehow. News of a hard-working intelligent person travels.
Attitude is half of the equation. Technical ability is the other half. Fact is, there are enough people out there with ability. (Fewer than you would think, but enough.) The real challenge is today’s world is to find the person with the ability who has a good attitude about working hard, and can get along with people. Those who score high on both counts will be highly sought after. Seems simple, but most people have one or the other or neither.
I’ve been asked questions such as “what college is best”? For me, that question misses the point. Sure, some employers favor candidates from certain colleges, but what we are all really looking for is candidates who understand the material enough to do a good job. That may not have anything to do with the degree. (Or even if you finished the degree. But don’t quit – that doesn’t look good at all, and some jobs literally require the degree for certification and regulatory reasons.) Believe it or not, it is possible to go through several years of college and get a degree, even with good grades, and still not really understand the subject that is featured prominently in the middle of the diploma. I know lots of people who studied engineering, beating their heads against it to get decent grades, but who, at the end of every course experienced this giant sense of relief on the way out the door of the last class as they tossed all of their notes and tests in the trash, hoping never to have to look at the stuff again. Well, fact is, you probably never will have to think about 80% of what you learn in college. But, some carefully unidentified 20% of what you learned will become a large important part of your life’s work. You need to LIKE it. If you are one who does not like what you are studying enough to look forward to your class work, you ought to find another field of study. If you interview with me (I’m not much different than others) I’ll know about five questions into the interview if you have any real interest and aptitude for the subjects that you studied. That is what I want to know, not where you went to school.
Finally, what happens to those I described above who don’t have an interest and aptitude for engineering but make it through school anyway? They find work, and after years struggling along below the earnings curve, some will eventually find work in another field that they like more, but a few of them bubble to the top of their field of study anyway and the rest of the smart ones end up working for them. They obviously don’t get to the top using their technical skills; they do it because they work very very hard, and they usually have outstanding “people skills”. They can organize, communicate, motivate, and generally get things done. I can’t tell you how much an employer appreciates the employees who are very productive and have that great ability to “get things done”. They will be paid well and shown regular appreciation.
The technically bright people often lack these other skills. The real stand out, and they are rare, are the few individuals who are technically bright and also hard working, organized, motivated, and get along well with others. Rare. If you can be one, and be seen, you will go far.
One last thought: In our work, lots of us have to travel, sometimes for weeks or even months at a time. Most single people like travel, at least at first. Marriage and children take the fun out of travel for most people, and even single people tire of it because it tends to keep them single. If you can sell yourself as someone really willing to travel, that will give you an edge with some employers.
- How can I apply to your company and when should I do it? For example, in my junior or senior year of college or when?
Either one, both, or neither. See the above. I’m sure you will get lots of good advice from school sources about when to apply to most large companies. Follow it. We are a small company. For us, it is simple: If we need you, and we see you, and we think that you can do what we need you to do, we will hire you. Else, not. Some of it has to do with timing. If we get a resume, or are reminded of a resume or a person at the right time, that will be the trigger. Sometimes we just contract with a person for a short time, for a project, but the person does such a good job (and we have the future work) so a short thing turns in to a long thing – employment for years. It just depends.
- What are the typical salaries in this industry?
Currently, if you graduate school with a GPA of 3.0 to 3.5 in electrical or software engineering or computer science, if we need you, we will offer you something in the range of $45,000 to $50,000. Over 15 years you can hope to nearly double that with a little help from inflation, if you are motivated.
- Do you offer any training courses I might be interested in?
Not really. One thing that we in particular use, that they probably won’t teach you in school is training in PLCs. That is Programmable Logic Controllers. There are several brands. We use almost exclusively those by Allen Bradley. There is a large market for this skill, so if you do take a course on it, it will not be wasted. However, you could also go a lifetime without ever working with one. They are used extensively in industrial automation and other control systems. The rides and attractions use them because they are very reliable and safe. If you work here, you will have to learn them. You will be far more likely to find work here or in this industry if you know PLCs and have some experience programming them or designing with them. Even just a course in PLCs would be a plus. Not many students see them in school. Just the “technology” degrees, not the regular engineering or software oriented degrees because with the later you will have not problem picking up PLCs. Still, for us, the more exposure to PLCs the better. A good text book is Programmable Logic Controllers by Petruzella, 1998, published by Glencoe/McGraw-Hill. Allen-Bradley teaches a course on it too, but it is expensive. I think most technology oriented community colleges will offer a course on it once a year – at least ours does.
- My major is computer engineering. What opportunities are there for me in the amusement park/roller coaster field? Who are some other companies like yours who do similar things?
A computer engineering major will have plenty of opportunities. If Disney is hiring when you graduate, they will be your best shot. I’ve attached some links to organizations with member lists that you can look though. It will be hard to find a job as a new grad at a small company unless you are known to them as a promising candidate who works hard.
- What is your field of expertise?
I am an electrical or electronic engineer by training. In practice, I am a control systems engineer (control systems are one aspect of electrical engineering). For most of my career I have supported the themed entertainment industry. Specifically, I design control systems for rides and shows. Most of this work is focused on safety control systems.
- Tell me about your education background. Schools attended, years attended, level of education, etc.
I graduated from the University of Central Florida with a BSE in electrical engineering, cum laude, in four years, in 1979.
- Did you always know that you wanted to become an engineer?
Yes, or at least it was fairly evident from a very young age. My father was an engineer and I was always interested in the things that he would talk about. Then, in school, math and science always interested me more than other things. My father however worked for Martin Marietta Aerospace and said that a lifetime of working on bombs was not much fun so he did not necessarily recommend I become an engineer. Fortunately, I wound up in the theme park business. Even that gets old after awhile, but at least it’s fun to tell your kids about it.
- Tell me about your work history. Do you now own this firm?
During the summer after the 10th grade, I took a summer job digging ditches for the Orange County school system, connecting portable classrooms to the main school buildings so that they could have intercom, class bells, and fire alarms. Eventually I was allowed to connect the wiring myself. Then I was moved up to helping with the intercoms, and then television repair work. After three summers I had learned a lot, however to this day I feel that most of what I learned before college came from my father at home, and all of this was a big help to me in school because it gave the things that I learned in college more meaning. Meanwhile I had started a beekeeping business, selling honey by the 55 gallon drum in order to accumulate money to go to college. I kept the beekeeping business going through the first three years of college. That, together with working at Disney on the weekends was enough to pay for college. After graduating, I had three job offers; BellSouth, Martin Marietta, and Disney. I got the interview at Disney because one of my Disney supervisors knew that I was about to graduate as an engineer and arranged the interview for me at Walt Disney Imagineering in California (back then it was called WED Enterprises). The design of EPCOT was about to begin. Disney’s was the lowest salary offer, but sounded more interesting, so I took it. I was assigned as control systems engineer for the American Adventure Pavilion at EPCOT. I worked at Disney for five years, 1979 until 1984, moving up from associate engineer to engineer, to Senior engineer, to ride control group leader. In 1984 I started Birket Engineering. Yes, I do own this firm.
- What are some of the challenges that you faced while in school? How did you overcome the challenges?
The challenges will depend upon your personality. For me the challenge was finding the time to fit everything in. I had to keep my little business going to pay the bills, work weekends, and manage an intense homework load. In less you are extraordinarily brilliant, you must plan on spending several hours a day studying and doing homework if you intend to get good grades and learn the material sufficiently to survive the interview that will get you the job you want, and then survive the job. As for how I overcame the challenges, I developed the ability to focus and exercise self-discipline. I worked very hard. I believe that hard work is the most certain solution to most of life’s challenges.
- What are some challenges you faced once you finished your education? Did you find a job immediately? How did you get to the point you are at now?
The job market for engineers was a little bit soft at the time that I graduated in 1979. People told me that I had made a mistake by choosing engineering. At that time most engineering jobs were defense and aerospace related. The job market was therefore reliant upon government money which would come and go with changes in the political environment. People would tell me to expect to have a hard time finding a job, and to expect periods of unemployment. I clearly remember answering them with this, “As long as they need a few engineers I will have a job because I will be one of the best. I will study harder at work harder than most of the rest, so I will always be one of the few that has a job.” I remember thinking that it was probably arrogant to say that, but honestly that has been the approach that have used all of my life and it has worked.
- If you could go back to when you began studying for an engineering career, what would you do differently?
I would have studied even harder. There have been so many situations throughout my career where I wished I could better remember some of the material that I studied my classes. I would also have taken more time to make friends along the way. Now, how to do both at the same time, I don’t know.
- What advice would you give to an engineering student at Valencia Community College? Are there any challenges that they should be prepared for?
I would say this. Do not attempt to study engineering unless you have serious interest in math and science. Without this interest, you may get through the curriculum and get the degree but if you interview with someone like me I will know about 10 minutes into the interview that you only learned enough in your classes to pass your tests. I have interviewed plenty of engineers who actually had fairly good grades but did not remember what they studied because they were not interested in it. I avoid giving them jobs. You will probably also not like the work, if you can find it.
Having said that, I’ll also offer another quite different thought. There are a number of jobs that require a engineering education but which do not require that you use the most technically challenging aspects of that education. In fact, the engineers who are best at the most technically challenging aspects of the profession are often not the best at organizing and managing engineering projects, or selling the results of that work. So, some engineering graduates who are not as fond of the math and science eventually find themselves with a great career selling or managing technology. Be careful though, because it will be difficult to find and survive that first job based upon your technical abilities while you are trying to be discovered as a manager or sales engineer.
Another important factor for you to consider, which I did not have to deal with when I graduated is that the world has changed radically in the last 20 or 30 years. For every one of us here in the United States there are four in China, and another three in India. Unlike us in the United States , those people in China and India have not come to believe that life is easy. Simply put, they work harder than people raised in this country work. They study harder in school. They want the job that you want and they may be able to take it from you because they are willing to work much harder.
As an employer, I have learned to favor employing people who were born and studied in other countries because, on average, they work harder. If I can employ them in their home country, they will work for a fraction of the wages that are expected in this country. My competitors have learned this also, so if I ignore this fact I will be out of business because my competitors will use labor from overseas and be more productive than my company. It may disappoint me that I cannot look out for my fellow Americans by providing them jobs, but if my fellow Americans cannot work as hard as the foreigners for the same wage then I have no choice but to hire the foreigners.
In addition to this company here in Orlando, I have a company in China. A few weeks ago I was interviewing engineers in China. I was very impressed. They remember more of what they learned in school than the engineers that I interview here. They expect to work harder. They expect to make one tenth of what engineers here expect to make. These are all engineers that were studying English and Japanese at the same time that they were studying engineering. If you have grown up living the good life in the United States, you simply do not understand what I’m saying, but understand this: it will affect your life. Plan accordingly.
“The 19th century belonged to Great Britain. The 20th century belonged to the United States. The 21st century will belong to China.” That statement has been quoted so often that that I have lost track of who said it first. If you do not want to be passed up in your lifetime, work hard and be prepared for serious changes in the world you know now. You might even consider learning Mandarin while you study engineering because the engineering graduates in China are definitely all learning English in addition to engineering.
Glenn A. Birket, P.E.
Roller coasters are an excellent (and fun!) way to illustrate physics concepts such as kinetic and potential energy, momentum, friction, and so on. However, at Birket we design and program the computers that control roller coasters, not the mechanical parts. The closest thing to a roller coaster model that Birket has done is creating a physics-accurate computer simulation to display ride vehicles moving around the track and virtually interacting with our ride control system. We have also built a 3D-printed model of a roller coaster train to help market our onboard lighting capabilities, although this was a static model and therefore wouldn’t be very helpful in explaining physics concepts. Physical models can never be as accurate as a computer simulation, so in our industry they are typically reserved for marketing purposes and visualization only.
However, I (Ryan O’Neill) have some personal experience in building functional roller coaster models over the years. The K’Nex building toy used to be the main method for constructing models through the ‘90s and early ‘00s. They are easy enough to assemble for novice model builders, yet versatile enough that you can create advanced features like cable launches and elevator lifts. CoasterDynamix also makes roller coaster track and trains which can be used (either exclusively or in combination with 3D printed parts) to build a functional model. CoasterDynamix models will look more realistic out of the box, but are not as versatile as K’Nex for building advanced models. Nowadays, it is becoming increasingly popular and accessible to 3D print roller coaster models from scratch.
I recommend starting with an off-the-shelf building toy like CoasterDynamix or K’Nex, since they’re much more hands-on and easy to adjust while you’re constructing the model. For more advanced models, 3D printing allows you to get a lot more detailed and design custom parts, but it will take much longer to build (and a lot of that time will be spent designing the model on a computer instead of hands-on building). There are resources and communities out there for hobbyists who build model roller coasters and would be glad to help you with your project.
It depends on how big and heavy the vehicles (trains) are that must be lifted, and how fast they need to be lifted. That depends on how many people will need to ride per hour. The motors might be anywhere from about 20 horsepower to 200 horsepower on a roller coaster.
- How much energy does each ride take to run?
Lets suppose that a 150 horsepower motor is needed to lift the train on the roller coaster that you are building. To figure that out in watts multiply by 746. That is 111,900 watts, which is 111.9 kilowatts. To get the energy, we have to figure out how long we need that power. If it takes 1 minute to lift the train to the top of the hill, that is 1/60th of an hour. So, 111.9 / 60 gives 1.87 kilowatt-hours of energy. There is your answer: in this example, it takes 1.87 kilowatt-hours to lift a train to the top of the first hill. After that, the ride is free! An ordinary 60 watt light bulb would have to burn for about 31 hours to use that much energy, but that much energy only costs about 10 cents! Compared to what it costs to maintain the ride, the energy is probably not a big expense.
- What is the maximum amount of energy it takes?
Like the size of the motor, that depends on lots of things.
- There are several points at which we could begin a discussion. Are you asking about how the block zones are created? Do you know what a block zone is?
To put it in perspective, the design of an average roller coaster control system takes about 1500 hours, plus another 1500 to build, install and test. (That is for someone who has experience designing many roller coaster control systems.) Average cost: $400,000.
- I think the block zone works by sectioning the track into zones where each train is monitored… once the train is past a certain block then the next train can safely be launched without risk of injury… this can probably be optimized for maximum throughput… am I right?
Excellent! Every zone ends with a brake, on a true roller coaster (as opposed to a vehicle with it’s own motor) the brake is usually a pneumatic device that pinches a fin on the bottom of a passing vehicle.
The entire track is divided into zones of lengths selected so that given the speed profile of the vehicle, each zone will be occupied for an equal time period. You will agree that the total number of zones must be equal to the total number of vehicles on the track, plus at least one zone so that the vehicles can progress. In practice, to maintain a smooth and continuous flow of vehicles around the track, there will be a number of zones equal to at least two times the number of vehicles, often many more. The load and unload areas, as well as any “wait”, “hold”, or “slow-down” areas are all zones too. They are just very short zones. Here again, the key is to make all of your zones of equal time. This involves understanding the ride dynamics and the people dynamics, i.e. how fast people are likely to get in and out of the vehicles. Next, you have to consider issues of vehicle length and how the apparent length may change in the curves. Also, consider how far the vehicle will penetrate a closed brake before stopping, with a worst-case entry speed. Often brakes cannot physically be mounted where you need them so compromises must be made. Lots of study goes into the zone layout. There are some tricks and interesting solutions that can be used to solve problems. Rides are delivered for a specific guest capacity. The zone layout is critical to obtaining that capacity.
Obviously, the point is that the control system does not open the brake until the zone ahead is clear. Sometimes two clear zones ahead are required. The brakes are normally closed so that every vehicle is normally moving toward a brake that will stop it unless conditions permit passage. Great effort goes into the design of the brakes and the control system to insure that if anything fails, the result will be brake closure. Mechanically, that usually means that the brakes are held closed by multiple large springs. To open the brakes requires air pressure and a long list of other conditions. Creating that long list of conditions can take 100’s of hours.
- Is it possible to create a rover car to run through the track with a high speed camera mounted on it so that the structure can be inspected thoroughly? or what methods are used to inspect the structural integrity of the entire structure?
Possible but not common practice. Things like this have been considered but are either not needed or are not cost effective. Inspections of structural integrity are usually done the old fashion way. Maintenance personnel walk the track and climb the supports each morning. Really. They sign off on the inspections. Some things are inspected less often than others. Areas of special concern are monitored by the control system, but these are simple things, usually.
- How can we guarantee that trains won’t collide with each other?
That is the job of the block zone system. That is the main point of the control system: to manage the block zones to maintain train separation. And 75% of that effort is about considering all the mechanical and control equipment failure scenarios, including the ones that are almost certain to never happen over the life of the system. Big topic.
- Is there any way of creating an automated system of inspecting the cars for damage to the frame or wheels?
Yes. Sometimes we monitor the gap between the frame of the vehicle and the track at selected points. The values are very consistent until mechanical deterioration begins. Even more common is monitoring a vehicle’s time in the zones. There is a well defined normal range of times for each zone, determined empirically after operations begins. Anything out of the ordinary demands an explanation. Usually we just annunciate small deviations but shut the ride down instantly for larger deviations. That is often part of the fail-safety of the system.
- Since we want to use LIM’s what are the safety considerations of controlling large voltages, and does Birket design the controls for the LIM or do the manufacturers do that?
We do part or all of this work. The safety issues related to the high voltages are generally addressed by following the National Electrical Code, NFPA 79. That is a “cookbook” kind of thing. Not too hard. Expensive equipment, though.
- If we are using an LIM what would we use prevent the train from rolling backwards if it happens to stop in the middle of the ride during a loop or higher elevation. We were thinking of using some kind of ratchet. Are we on the right track?
Right now I can count all the world’s LIM launched coasters on my fingers, so you can make this up as you go along just like we do! Except for one coaster being discussed now, the LIMs are always on a level section of track, so no anti-roll back is required there. If your LIMs are on an uphill grade then you will need anti-roll back there, just as on a conventional coaster with a chain lift. Yes, the ones I’ve seen are a ratchet device. I’ve seen various designs. I’m not a mechanical guy at all, so I don’t notice much about the anti-roll back design. Seems sometimes that there is one dog (is that the right word?) beneath the vehicle in the center, and sometimes two, one on each side. Sometimes the mechanical design is altered to reduce the noise.
Anti-roll back is usually used only in one, maybe two places on the track, and as a “device of last resort” at that. If your LIMs are on a grade, the anti-roll back would take on great significance, unlike with a chain lift. On a normal ride you are just worried about the chain breaking – not likely.
In other areas of the ride, like all the hills and valleys, we do not use anti-roll backs of the ratchet type, although I don’t see why not. We just use pneumatic brakes. These brakes are always closed. The computer opens them for a second to let the train pass if the zone ahead is free. They snap shut behind the train so that if the train comes back to the brake (and it does happen) the brake will stop the “roll back”. Obviously if there is any possibility of this happening you will need at least two brakes between trains, else you will have two trains colliding in the brake! (Brakes are usually very short compared to the vehicle length.) It gets complicated.
Sometimes, like if there is a bad bearing on a train or anything else to slow it down, a train will “valley”. It doesn’t make it over a hill, comes back, doesn’t make it over some previous hill, keeps going back and forth and finally settles in a valley. They winch it out. Not a good thing. From a safety point of view though it is ok as long as the block zone control system holds the next train in the previous zone. As you see, there is much to consider and study, because you don’t want to find out about these things after the installation is complete. Most of “design” time is study of the “what-ifs”. There are formal approaches to this study called “Fault Tree Analysis” and “Failure Mode and Effects Analysis” about which large boring books have been written. (Did I say that?) It is very important stuff.
- When the passengers are unloaded off the train, is there a central control button where all restraints are released? In addition to the central control, is there a physical mechanical device where it can override the electronics. If there is can you briefly describe how the device works?
Yes, in the operator’s booth, or sometimes it is track-side. It depends on the layout of the ride and the park’s own policy. Sometime we program it so that it takes two operators to release the restraints. Same with the gates that open to let people on the vehicle. Yes again, there is always an override. Usually it is mechanical, usually right on the vehicle. We controls engineers like that because it keeps us out of the hot seat when our equipment fails. In other words, it is one less failure mode we have to study.
How it works. Pneumatics again, usually. Usually the vehicles will have a “button” or lever under the vehicle or along the side near the bottom. Pressing it releases the restraints. The control system controls the brakes in the unload area so as to position the train with the buttons or levers adjacent to plates that are operated by a pneumatic cylinder. When the controls detect that the train has stopped and is in the right position, the controls activate the air valve to press the plate on the button. The manual release is just to go press on the button or lever yourself, which may require a pry-bar or some other mechanical advantage.
- What are the main physical problems we should check by maintenance? We think of weld cracks, loosing of nuts & bolts, etc.
This is mostly a mechanical issue, since we build most of the control system components to be self checking these days. After maintenance walks the track to check the thing you mention, there is a start up procedure each morning. In our systems, the control system requires that an operator walk to every Emergency Stop button, and there may be dozens located all over the load, unload and track areas, and press each one. Each time it stops the ride, requiring use of the key to restart the ride. It can take several minutes, but when you are done you are very sure that all of the buttons work. (We do other things to make sure the buttons have not been tampered with, but this is the final test.)
Then, after the computer has witnessed every button being pressed, the computer requires that it see a vehicle actually be caught in every brake, since if thing go normally during the day the zone brakes never actually get to catch a train. On our best system, the computer actually measures the capture force or the distance penetration of the vehicle into the brake. If yours does not do this, you should at least have maintenance stick something into the brake, let the brake snap shut on it and then tug on it, to make sure that the brake has a strong grip.
- What controls are used to make the ride failsafe even with an operator error?
We try hard to get it down to the point where there is only about one mistake that an operator can make. That is pressing the go button before everyone is fully seated. Eventually, we will find away to monitor that everyone is seated, and in some places we do now, but it is difficult. Operators, usually paid minimum wage and bored stiff, make lots of mistakes. We take away from the operator every action we can, especially the repetitive ones. On some rides, the only repetitive action for the operator is to press the launch button when everyone is seated. We even light the button that he/she is to press when the train ahead is clear.
Basically, the computer knows (because we program it in software) what the next logical operator action should be, and when that action will be safe. For example, the operator can hold down the dispatch button or press it repeatedly, and nothing will happen until conditions on the track ahead are correct. Further, if the computer sees that the button is pressed too soon (depending on the nature of the ride and park policy) the computer may be programmed to ignore further operator action until a maintenance person inserts a key to clear the error. Similarly, if a button is to be pressed and released, the computer ignores it after it has been held for about two seconds, even if conditions for the button’s use become correct while the button is being held down.
Restated, the computer knows the location and state of every vehicle. If an operator’s action is not appropriate for the state of the ride, the operator’s action is ignored. (Depending on circumstances, the operator’s mis-dead may be printed in a log file for review, but not usually.)
One trick we use to keep operators on their toes when pressing the dispatch button is to give them two buttons, spaced about two feet apart. The computer requires that they press them at the same time, within about .1 second of each other, and for not more than about one second. We position the buttons so that the operator must be facing the vehicle to press the buttons. Also, we light a light to tell them just when to press the button. We may put the light in the distance, just beyond the vehicle, so that we know that the operator was looking at the train when he/she pressed the button. In some cases, we will require that two operators do this at the same time, from two different locations. This starts to get extreme, and we have the lawyers to thank. In some rides the computer monitors the seatbelts. Scanning lasers and imaging has been discussed to see of the riders are properly positioned and seated. And so on.
A few years ago this was not true. Operators were critical to the operation. They actually operated the brakes with switches or a big levers. No more. They just can’t be trusted, at least not against the cost of today’s lawsuits, which is sad in some ways. The same is not true of maintenance operators. Since these people are not doing repetitive actions and usually have a greater since of responsibility, they often do (and must be able to) make some important decisions. This is required because they deal with the unusual circumstances, like adding and removing trains from the track, positioning them for maintenance, and fixing things like trains caught in a valley. We program the computer to catch the worst of their mistakes but not every little thing.
When all is said and done, do you know what gets people hurt on rides? They try to get out after the ride starts. Usually, it is a kid goofing around, or even an adult. On a modern ride, you are VERY safe if you just stay in your seat.
This is certainly determined by the forces involved, but a typical brakes that we work with is by a company called Coastasur, or is it Costasur? Anyway, the brass (?) pinching surfaces are about 2 inches high by maybe 4 feet long. Multiple units are used to slow the train in fast areas. Almost never is a single brake used (although often one would do it, such as for simple holding applications) because of the “single point of failure” issue. The fin is usually tall enough to well over-penetrate the pinching surface of the brake. Fins generally run nearly the full length of the car, and usually every car in the train will have a fin.
As I remember from school, it is not so much the contact area but the force normal to the braking surface that determines the braking force. It comes down to the amount of time that the fin is in a brake with a certain pinching force. But don’t quote me on that. I’m an EE.
In our business, we are told how many brakes of what type there will be. Our job is to control them. Often we will note problems with brake failure scenarios, and therefore require that the ME give us more brakes for that reason, or we may tell him that for train logic reasons he doesn’t need certain brakes, but the brake’s ability to be a brake is not our business.
- How is the section of the bogie or the underside of the car designed to allow the track mounted booster wheels to do their job?
Not my area of expertise, but I’ve seen two general types. A flat platen under the vehicle upon which a single rubber tire with a horizontal axis bites. The reaction forces are a problem with this design (holding the vehicle down on top of the drive wheel) so more often pinch rollers (vertical axis of wheel rotation) are used, operating on the brake fin. The roller draws the fin in and pushes it out. Either arrangement can also be used as a brake, but the motor drive must be properly selected so that the motor can absorb the energy under control (dynamic or regenerative braking, where the motor becomes a generator.) With all of these arrangements, tire wear is an issue. They (MEs) work hard to reduce the slip. They often ask us to do things with motor control to help. For example we can detect or predict the vehicle’s entry speed, set the motor speed accordingly, then after we have “caught” the vehicle apply the accelerating or decelerating forces.
Then there are the rides we do with LIMs, which have no frictions points.
I know that was not what you were looking for in an answer, but maybe useful.
- Where are the tanks or reservoirs for the hydraulic fluids used in the restraining system located?
If you mean the on-board restraints, like lap bars and the like, there are never (that I recall) any on-board energy sources or reservoirs. The on-board device usually works against a spring, usually with a ratchet mechanism. An off-board actuator in the load area is often used to press a button, lever, cam or something that releases the restrain. Our job is often to position the train in the load and unload areas with enough accuracy that the actuator can hit the mark to release the restraints. Sometimes they make it easy for us by making the releasing actuator run the length of the area so it hits all the release points with ease. The actuators are generally pneumatic, and operated from “house” air pressure of about 80 PSI. We control a solenoid to actuate the release.
- If electric signals are used to activate/deactivate the hydraulics in the station, what type of material is used for the receiver and would that receiver still be located on the side of the ride down toward the bottom?
By “receiver” do you mean a device that receives the electrical signals that control things like brakes and release platens? If so, the generic name would be “transducer” and since your brakes are usually pneumatic, your transducer is either going to be a solenoid operated valve (that is either open or closed to air) or a proportional valve (that can carefully meter air flow).
Either way, this valve can be mounted most anywhere as long as the air lines between the valve and the actuator (cylinder or bellows, or whatever) don’t get too long (because of the delay to fill the lines with air). In practice I notice that they try not to go much over about 20 feet, and for some applications requiring fast action or tight speed regulation they will keep the distances to a couple off feet. The valves are usually located in a water tight box under or adjacent to the track. This box also serves as a termination point for the pressure sensors that we use to monitor the proper operation of the brakes.
- In the last e-mail you sent to me you told me that the on-board restraints are usually only springs with a ratchet mechanism. My simple question then is how are the on-board restraints actuated and held in position? For example, the restraints which require no rider involvement and are self positioning or which are free to move about until the operator locks them into place. What positions or activates the spring and ratchet which makes up the lock?
Imagine a lap-bar or what ever kind of restraint. The train is sitting in the load area. Let’s say the release mechanism is actuated, and remains actuated. (Some are maintained, others only momentary to release, it depends on the park’s preference.) In this configuration, the lap bar can be pulled down onto the lab of a seated rider, but when you let go it will move by spring action back to the up position. Now, imagine that we deactivate the release mechanism. The ratchet comes into play now. When the rider or operator pulls the lap bar down (against the spring) the lap bar stays there because the ratchet holds it in place. The ratchet has many detents to account for the various sizes of riders. The rider (usually) or the operator (if the rider didn’t do it) pulls or pushes the lap bar down until it is snug and the lap bar stays there until the train enters the unload area where the trackside release mechanism pushes the “button” to release the ratchet. While on the ride the rider can always tighten the lap bar, but never loosen it. The release mechanism, operated from trackside by levers under the train, just pulls the dog out of the detent in the ratchet. (I’m not sure I’m using the mechanical terms correctly, remember, I’m an EE.)
- Do hydraulics within the station (loading area) activate these mechanisms then retract? I presently feel comfortable in my understanding of the unlocking process, but its converse is really bothering me in my sleep.
Yes, it could be hydraulics but I’ve always seen it as pneumatics. Save the messy hydraulics for the places where you really need the incompressible nature of hydraulic fluid. A air operated pneumatic cylinder with a plate on the end of the rod can push the “button” on the side of the train, down low, to operate the mechanism, by levers, that pulls the dog out of the detent so that the lap bar will go up under force of the spring. That sure beats trying to figure out how to get some form of energy on board the vehicle.
- Also, in my question about the design of the underside of the car and how it allows for the booster wheels to do their jobs you mentioned the absence of friction points with LIM systems. Could you please go into depth about how that effects the design, or how the LIM is used in contrast to booster wheels?
Are you familiar with Linear Induction Motors? They do not need mechanical bearings. They are like a motor (which is a round thing) laid out flat! Instead of spinning a shaft, the magnetic field that is created by what was the stator of the motor now pushes a flat metal plate along the flat surface of the motor. Attach that plate to the vehicle, and line up a bunch of these stators and you have a vehicle propelled by a moving magnetic field. There are lots of trade-offs here. Linear Induction motors are neat but very inefficient. They will also burn up if you run them for more than about a second with out a plate to push on. But they do eliminate all that squealing and chaffing that occurs when the booster wheel (spinning at a preset speed) encounters a vehicle moving at a different speed.
I expect that there is info on the Internet somewhere about how LIMs work, although they are not very common. I expect that only maybe 10 rides in the world use them. We have done three and I know of only two other coasters that use them, one ride at Disney, and a People Mover in Houston. I’m sure there are others, but they are uncommon. Roller coasters mostly use friction drives (your booster wheel, I think), chain lifts, or in the case of water type rides often lift belts are used.
There are a few that use a sling arrangement. Imagine lifting a big weight, hooking it to the vehicle by a cable with a hook at the end, then take the brakes off the vehicle and drop the weight.
Birket Engineering does not design LIM motors. We do design control systems for LIM motors. We do not have any diagrams of the actual motors or any written information about LIM motors to send to you. We work with a company in England called Force Engineering. They designs the LIM motors that we work with on roller coasters.
Since you are interested in applying LIM motors to new applications such as subways and elevators, I can give you a some thoughts about the characteristics of LIM Motors as we have come to understand . LIM Motors have some unique and desirable characteristics, but like with most things, the advantages are usually accompanied by some disadvantages.
LIM motors are similar to regular motors in many ways. The motors can move a vehicle in both directions in can by used to stop the vehicle without the use of mechanical breaks. (Run them backwards and turn them off before the vehicle starts going the wrong way.) A major advantage of LIM Motors is of course that there is no wear due to friction because there are no bearings or rotating parts.
Disadvantages and other considerations when using LIM Motors:
The motor cannot be left on when the vehicle is not there to push against. This causes the motor to overheat and possibly burn up. A regular motor can just sit there and spin with out a load on it. Not so with LIMs. Therefore the control of the LIM becomes critical, to make sure it is turned off almost instantly after the vehicle passes and is not turned on again until just before the next vehicle arrives.
Each motor must be designed to propel the vehicle within a certain range of speeds. In other words as the vehicle goes faster the motor that started the vehicle from a stop is no longer effective. Likewise the motor that is effective for keeping the vehicles moving at higher speeds is fairly useless for starting the vehicle. To go from a stop to about 50 MPH in a few seconds requires that the vehicle pass over a succession of at least four different types of motors, each built to operate at a different speed.
In addition to generating a strong force to move in the forward and reversed directions, LIM motors develops a strong force pulling the vehicle toward the motor. This must be counteracted by a strong suspension system on board the vehicle to maintain the separation between the motor vehicle. One solution to this problem is to place two motors together, facing each other with a gap in between them. Then a fin on the bottom of the vehicle is run between the two motors. Now the motors will propel the vehicle along the track without pulling it down. Even this leads to another kind of problem. The motors now pull toward each other with such force that they can collapse their own housings. Therefore the motor housing must be built of very strong materials.
I am aware of two subways that use LIM motors. The first is the “people mover” at the airport in Houston, Texas. It was designed by Walt Disney Imagineering in cooperation with Turner Construction. The project was finished in about 1981 and is still operating successfully.
The second installation is the subway that transports U.S. senators from their offices to the Capitol building in Washington D.C. The system is similar to the Houston project. Both designs are based upon the original work done by Disney for the Disney World “WEDWAY” attraction at Tomorrowland in the Magic Kingdom.
It may indeed be possible to use LIM Motors in an elevator application. I don’t know if this is been considered before. I would want to talk with someone who is more of an expert with these motors than I am, before I tried it. I have heard in the news that LIM Motors have been considered as a part of an accelerator to launch (or to assist with the launch) of vehicles into space. This would be a very elaborate system requiring a tremendous amount of power. I think it will be many years before we see anything like that.
Designing roller coasters is definitely a lot of fun, and a lot of work. It requires a lot of study and training in school, followed by years of experience before you can lead a design project. It can be a good way to make money. However, many people want to be doing this, and many companies want to be in this business. There is not enough work for all of these people and businesses to get what they want! That means that if you really want to do this, you will have to work very hard and be the best person for the job.
The things that come to mind when people think of designing a roller coaster are the structure itself, the track, the vehicles that ride on the track, and all of the mechanisms such as brakes and motors. Design of these are the responsibility of civil, structural and mechanical engineers. Civil engineers design the preparation of the earth and select the types and grades of concrete to be used for the foundations. Structural engineers decide on the type and arrangement of the wood or steel for the support structure for the track. They must design not only to support the track and vehicles, but also to withstand wind storms and perhaps even the weight of ice or an earthquake. Finally, mechanical engineers design the mechanisms which move and stop the vehicles, and the vehicles themselves including the motors drives, hydraulic systems, and the pneumatic systems which accelerate and stop the vehicles.
There is another type of engineering involved with roller coasters. It is not one that everyone thinks about. It is the type of engineering that we all do here at Birket Engineering: control system design. We are electrical, electronic and software engineers. We design the sensing and control systems, including the computers and software which determine when and how the vehicles move. Most of all, our job is to make sure that all of the mechanisms operate safely. Less than half of our work is related to making a reliable and fun ride. With some practice, that becomes the easy part. The majority of our time is devoted to the hard part. That is making sure that everything works right every single time, and that if something does break or go wrong, the ride stops in a way that no one will be hurt. Our job is to think of every little thing that might go wrong and make sure that we have a good solution for it that will work perfectly even twenty years later after we are long gone. It is a big responsibility because when people get on a roller coasters they trust that we have done our homework.
Homework brings me to the subject of school and how you might prepare to be a roller coaster design engineer. No matter which type of engineering you choose, your math and science will form the foundation for your college studies in engineering. During the four or five years of the engineering Bachelor’s program, all engineers take the same math, science and engineering courses. It is only about one to two years of study that separates the different types of engineers. To get ready, take all the math classes you can in high school, including calculus. Also take chemistry and physics in high school. You will want to take the honors courses or advanced placement courses if your school offers them. You might be able to get into an engineering college without the honors courses, but then the engineering math will not be your friend. You probably won’t graduate at the top of your class if you do not get off to the right start.
As important as math and science will be, you should know that engineers spend their days communicating, mostly in writing. All of our language skills are vitally important. Grammar, spelling, and foreign languages. The world is growing smaller all the time. About half of our work is in foreign countries. The engineers who work here have weeks and even months in Spain, Japan, Singapore, and China recently. We’ve worked in about a dozen countries around the world over the years and that trend will continue. Your social studies classes will help you – geography and history. It is so important to understand something about the cultures and customs of your customers. You should learn at least one foreign language. I mean really learn it so that you can speak it. I’m always impressed that our clients in foreign countries speak multiple languages. They are the ones helping us with our inability to speak their language. If you can speak their language, you will be more likely to get their business, and you will be able to do a better job, which means that you will get more jobs.
In addition to communication and the core engineering subjects, it will give you a big advantage to take elective courses like robotics, computer modeling, and programming if you have the opportunity while you’re in middle or high school. These courses will teach you not only the hard skills (like specific programming languages or modeling softwares) that are used in our industry, but also soft skills like critical thinking and problem solving. It will also give you an intuitive understanding of technical systems once you have worked with them before. For example, someone who has worked on a few robotics projects will have a better idea of what size motor is required, or whether a belt drive or lead screw mechanism is better for a certain application. Those are skills you can’t learn through studying – you can only learn them through practice by doing projects.
On the note of doing projects: they are often the best way to showcase your hard and soft skills in a job interview, particularly for themed entertainment jobs. They can be personal projects or group projects – it’s great to have a variety of both. Having a portfolio of engineering projects not only proves that you are passionate about engineering and have the skills to build things, but also that you are able to work in a team and communicate your ideas effectively to other people.
After you graduate from college, you will want to become licensed to practice engineering. You can work as an engineer without a license but you can’t be in charge of an engineering project without a license. To get the license you must first have a degree in engineering. It must be a full four-year degree, and not just an engineering technology degree. Then you take an eight hour test covering all areas of engineering. If you pass, you become an Engineer In Training. Then you work with experienced engineers for four years, some of whom are already licensed. Then, if they are willing to recommend you to become an licensed engineer, you may take another eight hour test on the more difficult engineering subjects. If you pass that test, you are a licensed Professional Engineer, and you can sign the drawings and designs of the engineering interns who work for you. If you don’t take any breaks, you will be about twenty–five years old at this point.
It will be very difficult to find a job with one of the few roller coaster design companies right out of college. You may be able to secure an internship at one of these companies, which will certainly be easier if you apply with one of the American-based companies (Premier Rides, Skyline, Great Coasters, Rocky Mountain Construction, Chance, and so on). Even though, as an intern, you will not be tasked with high-level decisions like creating roller coaster layouts, you will gain valuable experience and insight into the overall engineering process. The European roller coaster design companies (Intamin, B&M, Vekoma, Mack, etc.) may offer internships, but it will be harder to convince them to hire an international student if you are not familiar with living in those countries. You will need some good experience first, and it should be experience related to your field of engineering, and preferably also related to rides, theme parks or some aspect of the entertainment industry. There are several engineering students who keep in touch with me by email, always asking for part-time work, summer jobs, or any contacts that I may have in the industry so that they can get that experience.
So, if you want to be a roller coaster design engineer, or any other well-paid professional, the answer is the same. Study long and hard, work hard, ask for help when you need it, communicate effectively, maintain the right attitude, network, and always work to be the best that you can be.
The type of energy used on a ride is usually changing as it is used. Most rides use electrical energy but the electrical energy is converted to other forms of energy using a motor. The motors push or pull the vehicles, creating energy of motion, called kinetic energy. If the motor pulls the vehicle up the hill, maybe using a lift chain, we say that the vehicle has acquired “potential energy” because it is now higher, and can roll back down hill. When the vehicle rolls down the hill, it loses potential energy and gains kinetic energy. Finally, when it comes to rest in a brake, some of the train’s kinetic energy becomes thermal energy as the brakes are heated. On some rides, so much thermal energy is captured in the brakes that water is constantly fed to the brakes to keep them from being damaged from the heat.
The majority of engineers working with roller coasters have mechanical degrees. Most of us at Birket Engineering have EE degrees, or Computer Science/Software degrees because we do the “control system” part of the coaster design. Specifically, we design the systems that keep the trains from getting dangerously close on multi-train systems. We also do the operator controls, track switch operations, and other “control system” functions. Some companies offer structural/civil engineering services for coaster designs, with regard to the foundations and other infrastructure items. But, for the classic potential energy = kinetic energy fun part of the coaster design, it’s the ME’s that are in the middle of the action.
Not really, except for local zoning and building permits, like are required for any thing that is built.
As for the safety of the design, it depends on the state and the type of ride. There are some “codes” for rides, but not many. Most of the codes are informal and established by the designers of the rides – actually that is the way most things are done in this country, much more than most people think.
Some states have inspectors especially for rides, but they stay busy checking on the carnivals. Sometimes, it is just the local building inspectors, and they can only check on a few things about the rides, because they don’t know much about rides.
The main reason that the rides are safe is because the parks will only hire the best designers who have proven that they follow the highest standards in their designs. We all want to do our best, and we don’t want to ever see anyone get hurt. The designers and the parks would all be out of business real fast if people started getting hurt on the rides.
Besides, since it takes many engineers many months of working together to design a ride, how could an inspector from the government ever have time to check all those calculations and design decisions. It is not possible. That is why we have standards to be a licensed engineer, and why the engineers are so careful to check each other’s work.
The power requirement for the actual CONTROL system is very small compared to the power for the motors that move the vehicle. All of the control power typically comes from one central control cabinet. We usually ask for one standard 120 VAC, 20 Amp circuit, so that would be 2.4KVA, which in this case is very close to 2.4KW. We probably only use 50% to 70% of that.
The more interesting power number is for the motors. I think you said you are using LIMs. I don’t know the numbers myself, but I know that they are very inefficient. For an estimate, I’d start by calculating the energy/time required to achieve the acceleration and speed that you need and then figure that the motors are about 40% to 50% efficient. I’m guessing at the efficiency.
Important considerations on LIM systems have included sizing the feed from the power company and selecting a transformer for the building that is adequate for the high current and in-rush demands of the motors, so that the voltage does not dip as the vehicle is accelerating. I don’t know the details of this issue because this was handled by another company. Power factor correction is also a big issue, but again, its not my area. Let’s see, motors are inductive so current lags, so they add capacitors (lots of big ones in this case) to correct the power factor. If this is important to you, you can ask a power engineer.