On November 23rd, I had the opportunity to attend a student design workshop for a new Automated Transit Network (ATN) system. This interdisciplinary project of San José State University involves the departments of structural, mechanical and electrical engineering, computer science, industrial design, urban planning, business, and public administration. The students and their faculty advisors have actively sought out the advise and counsel of ATN experts from around the world. The Mineta Transportation Institute (also at SJSU) and the City of San José Department of Transportation are also in communication with the student team.
The group met in an industrial building that they have temporary use of while the landlord looks for a new tenant. In the warehouse they have full-size mockups of three cabins, a station, and a 1:12 scale working test track. The cabin mockups are made of wood, styrofoam, and foam-core, and are intended just to get a sense of how the pod would look and feel. The station mockup has been coated with a finish that looks like the cast concrete that would be used in the final product. It also has a green wall on one side to soften the look and project a “green image”. Back in the meeting room there were posters on the walls illustrating the work of each of the design groups. The industrial design studies of possible cabin designs were particularly notable for their imagination, creativity, humor, and artfulness. Ron Swenson, of the International Institute of Sustainable Transportation (INIST) encouraged the students to think of the facility as an exhibition space that could be used to introduce visitors to emerging concepts in automated transit.
In his introductory comments, Ron observed that there are three kinds of people: those who make things happen, those who watch things happen, and those who wonder what happened. Each of the design groups, guideway, bogie, cabin, automation, and solar power, then gave a short presentation on their latest progress. The user interface group demonstrated a mock-up of their smartphone-based user interface. Following that, each of the groups claimed an office space where they could meet separately. But to promote interdisciplinary cross-fertilization, a few members of each team sat in on one of the other teams.
The students have taken up a number of questions that have been debated for years: Should there be a way for passengers to change their destination while en route. How do we handle emergency evacuation? Should there be some sort of special emergency vehicle that can retrieve people with disabilities? How about handling freight? Should stations be at ground level or elevated? Should there be advertising on or in pods and stations? Will passengers feel safe? What do you do if someone you are uncomfortable with wants to share a ride? Should stations be open, or will you need a ticket to enter? How do you balance the needs of safety and privacy? Will surveillance make people feel safer, or will it be creepy? Will people be content to sit facing backwards? What about people who are afraid of heights?
Since the bogie interfaces in many ways with the guideway, those two teams naturally have had to work closely together. The first guideway design for their suspended-cabin system had a rectangular cross-section. Later, they favored a tubular guideway design that had the advantage of providing an easy way for the cabin to tilt while cornering. More detailed analysis of that design showed it to be impractical, so now they are studying an I-beam guideway. This appears to have the advantage of a more compact, and thus less expensive, bogie. They are exploring a side-to-side hinge damped with a non-newtonian fluid so the pod could lean into a turn without being susceptible to swinging in a gusty wind. From the outset, a decision had been made to use conventional rotary electric motors. But the I-beam guideway looks to be particularly amenable to Linear Induction Motors, so they are now taking a second look at that. The I-beam guideway would require some sort of shroud to enclose it.
The system is designed to climb or descend at a maximum angle of 10°, and the cabin does not tilt forward and backward. That choice was made in order to reduce the size of the electric motor, but it means that it will probably not be practical for the pods to descend to ground-level stations. Perhaps a useful project for the future would be a study comparing the cost, complexity, reliability, and energy use of a system that descends to ground-level stations with a system that has elevators at every station.
Future plans include building a refined full-size cabin and a full-scale functional model of the bogie and guideway. Perhaps the most significant aspect of the project is that it is preparing a crop of students who are knowledgeable about automated transit, and excited about the possibilities. With about 60 students involved, it’s one of the largest ATN development groups anywhere. The urban planning students will be starting on the project in the Spring. For more info, check out the project website, or Sam Ellis’ blog.
I hope I can be forgiven if I insert here a few of my own thoughts on what the students have accomplished so far. All three of the full-size cabin mock-ups are GINORMOUS – big enough to accommodate six seated passengers plus several standees. They look to be only slightly smaller than the Morgantown PRT (Personal Rapid Transit) vehicles. Subjectively, I would estimate that their interior volume is about four times that of a typical luxury car. Perhaps this explains why the students have placed so much emphasis on ride-sharing. With vehicles the size of small buses, it does not seem to make sense to operate them with only one passenger. I once heard a structural engineer say that people mistakenly believe that the job of a bridge designer is to make bridges as strong as possible. In actuality, he explained, the goal is to make the bridge as weak as possible without it actually collapsing. In the same way, it’s easy to create a spacious cabin by making it bigger. But that also makes it heavier and more expensive. The challenge is to make the cabin as small as possible without sacrificing comfort and functionality.
There are other issues that relate to the height of the vehicle. According to the Automated People Mover Standard (ANSI/ASCE/T&DI 21–13) the maximum allowable lateral acceleration for standing passengers is 0.1g, but for seated passengers it’s 0.25g. This may seem like a small detail, but it has a profound influence on the layout of the guideway network. If there are standing passengers, turns must be wider, and station sidings must be longer. And because more distance is needed to come to a stop, headways (the spacing between vehicles) must be greater. That reduces the carrying capacity of the entire network. One student observed that people stand on buses even at high speeds, and when sudden stops are possible. But, fairly or not, automated transit is being held to a much higher standard. Another concern about extremely tall vehicles is that they can make it difficult to integrate stations into multi-story buildings. If the total height of the vehicle and guideway is greater than the distance from floor-to-ceiling, major structural changes will be needed.
The Automation Team (The A-Team) is planning a capability for users to reserve a pod ahead of time. This has introduced a number of complicating factors. What if someone reserves a pod, and doesn’t show up? What if you’re holding a pod, and someone else gets there first? It would be interesting to do a rigorous comparison of the reservation system with a first-come-first-served system.
After the workshop I went out to dinner at a local restaurant where I met two gentlemen who were in town for a convention of people with disabilities. Both had been paralyzed in motor-vehicle crashes.
So far the student’s efforts have been funded by about US$3,000 contributed by the students themselves. People who saw their presentation at the Podcar City 7 conference in Arlington, Virginia were impressed with how much they have been able to achieve with so little funding. At that conference they were awarded the $5,000 First Prize in the Solar Skyways Challenge sponsored by INIST. The board of directors of the Advanced Transit Association (ATRA) will vote in January on a proposal to budget $2,500 in matching funds to defray the cost of parts and supplies. If you have any interest in helping to match this tax-deductible donation and support this important work, please contact me. If I can’t answer your questions, I can direct you to someone who can.