Friday, December 31, 2010
It has been said, “History is written by the victors.” Well it appears that the victor, in the war of competing PRT standards, is the ULTra/2Getthere steerable design. It is reasonable to assume that the systems will work as advertised… well enough to get some new contracts while continually improving. Therefore:
“PRT” now means automatic, driverless cars that travel on pavement. It doesn’t really matter anymore that PRT started out as something different. PRT is, and will be, a short-range automatic shuttle service for airports, campuses and the like. PRT will require snow plowing, battery charging and replacement, and will compete for space with cars, bicycles, golf carts, or pedestrians. Get used to it.
The fact that some of us have tried (or are still trying) to craft PRT as a next century transit solution is beside the point. That is not what PRT will be in the minds of most people a decade from now. As the folks at ULTra proudly point out, they have more people working on “PRT” in their company than all other PRT companies combined. To those of us who see PRT’s potential as a means to a more environmentally sustainable and efficient future, I can only say we had better retool our message, and do it fast.
Of course Masdar and Heathrow will have one beneficial effect. They will demonstrate the viability of computer-directed traffic management for small, automated vehicles. At least that is one hurdle out of the way…but honestly…was that outcome ever in doubt?
Our goal will be, then, to widen the discussion to include less pavement, not more, higher speeds, longer distances, more efficient ways to deliver power to the motors, much larger scale networks, etc. It will be hard to talk about it, though, because the term “PRT” has switched from being overly inclusive to being downright misleading. Now discussions about PRT deployment for a city will logically begin with providing ground-level right-of-way, similar to mapping out potential bicycle lanes. Discussions about elevating significant portions of this “track,” I predict, will end pretty quickly, as the logistics become apparent.
I think I like the term “microrail PRT.” (Not to be confused with “MicroRail,” a small gauge train from MegaRail Transportation Systems Inc.) It is reminiscent of the word “monorail” but obviously refers to something smaller. Remember, most people have no idea what PRT is, and it takes a while to explain. Say “microrail PRT” and they might get a picture of a tiny monorail in their heads. (or maybe something on a roller coaster track) Either way, it’s minimal and elevated. PERFECT!
I think PRT, as it was originally envisioned, was really a multipart invention. It synergistically combined the concept of many small computer-controlled vehicles with the concept of an electrically powered light rail system that could be economically run above street traffic.
The cost of free-spanning, beam-like support structures, you see, is reduced exponentially (I’m using the term informally) as their weight bearing requirements are reduced. It’s like fleas jumping 200 times their body length. Some things are possible only at smaller scales. The lightest human-carrying vehicles are in a weight range where a single-beam track can be almost ridiculously cheap, especially when compared with the other options in densely populated areas. It is true that access-for-the-disabled laws, or any scheme that enables capacity much beyond the average (110kg for autos) occupancy greatly increases track costs. That was a clear lesson of Raytheon’s PRT debacle. Nonetheless, carefully designed vehicles can still allow track costs that would enable a true transportation revolution… of that I am convinced. This is both the challenge and promise of PRT… er… microrail PRT…hmmm… microrail podcars? Automated Microtrack Transit? Autonomous Minirail Transit? HELP! We need a new name!
Happy New Year!
Posted by Dan at 9:21 PM
Wednesday, December 22, 2010
This just in!… After persistent rumors of a historic PRT deployment above the Artic circle, intrepid reporter Dan the Blogger goes to the North Pole to interview the big guy himself. That’s right, folks. Santa Claus himself has made a “ringing” endorsement of PRT technology at his northernmost campus…Here are excepts from the interview…
Dan the Blogger: “Santa, I must say I’m a bit surprised to see you adopt such cutting-edge technology. What made you turn to PRT?”
Santa: “Simple logistics Dan, I run a tight ship here. It’s a pretty big enterprise. We’ve got daily shipments coming in…one hell of a payroll…I can’t be wasting time stuck up to my keester in snow, trying to get the reindeer hitched-up. What’ya think? I should snowshoe all the way from the house to the workshop? And it’s worse for the elves, ya know…I used to have to issue periscopes and shovels or they’d get lost entirely!
Dan the Blogger: “It looks like you went with Vectus. Any particular reason why?”
Santa: “Have you ever tried to fit a reindeer in one of them “Skyweb” things? Damn uncomfortable for the reindeer, I’ll tell ya.”
Dan the Blogger: “Wow, it seems like you really put PRT to good use.”
Santa: “That ain’t the half of it, Dan. I even got track runnin’ between the warehouses and the docks.”
Dan the Blogger: “the docks? I thought you…”
Santa: What? Fly everything from here in a single night? What are you in? The 1860’s? The stuffs gotta be staged, ya know…I got warehouses all over. Plus I got ships comin’ in from China almost daily.”
Dan the Blogger: “I….I thought the toys were made by elves…”
Santa: “Chinese elves, Dan. “…do a wonderful job.”
Dan the Blogger: “My readers are probably wondering what you think of having the linear motors in the track instead of on board… I guess that probably saves weight and space as well, doesn’t it?
Santa: Don’t need motors, Dan. I just tie some cars together and put a reindeer in the front one. Works like a charm…. Hey, I gotta get back to it, ‘less you wanna see 5000 little girls get headless dollies…
Dan the Blogger: Thank you Santa, for this interv….
Santa: “yeah, yeah,.. Keep your stick on the ice, fella… oh, and Dan…”
Dan the Blogger: “Yes, Santa…”
Santa: “You know damn well I can’t give you THAT kinda thing for Christmas…”
Dan the Blogger: “Yeah, I know…”
Dan the Blogger: MERRY CHRISTMAS EVERYONE!
Friday, December 10, 2010
For some time now I have advocated designing PRT for more than strictly CBD (Central Business District) use. Even though the “flight to the suburbs” in the U.S. has led to the need for urban renewal, and PRT would be a terrific tool for just that, the suburbs and highway fed satellite communities already exist, and need service too.
Companies wishing to get a PRT product to market do not have infinite time and development dollars, and their efforts necessarily must start from the basic building blocks of stations and loops. There is little point in promoting a vision that they are not yet prepared to follow though on. Unfortunately, a scaled-back, slow version of PRT is a lot like a scaled-back, slow version of the Internet. Eighty people being able to dial up a dozen sites won’t exactly make you thunderstruck by the possibilities. Yet that is a stage that was, at one point, a future vision.
So here’s a little peak at a PRT “trunk” line, which, of course, can only happen when there are massive networks on either end to feed it. In this picture there are four tracks going in the same direction. Reversible lanes would offer up to five possible configurations, direction-wise.
Here are some sample numbers. With a one second headway, and vehicles traveling at 60 mph, (88 ft. spacing) and the U.S. average of 1.2 passengers per vehicle, the capacity would be 17, 280 passengers per hour. Not bad for fitting over a strip of grass no wider than a residential driveway! With vehicles that can swing forward from sudden deceleration and bumpered bogies that clamp the track for extra stopping power in an emergency, still shorter headways and higher speeds can be expected without much technological challenge, especially if platoon strategies are employed. I think what is informative here is the capacity vs. the minor amount of steel and concrete needed to achieve it. By the way, with rubber wheels inside of a sound-insulated track casing, the system would be nearly silent.
It occurs to me that when I invent, I frequently start at an endpoint or finished product and work backwards toward the present. In a world of cause and effect, one can start at the desired effect and try to envision the causes that could create it. This is why I have been advocating a standards-based open-source PRT solution. Can you imagine a single company ever being able to successfully scale up to this kind of volume? I can’t. The only way I can see it is if the track is a simple and standardized design, buildable by local firms, the control system is infinitely extensible, and multiple manufacturers can compete for business with certified, standards compliant vehicles. The funding needs to come out of the highway budget, and there needs to be a non-profit organization specifically tasked with organizing and fostering the public/private partnerships to make the whole thing happen, as well as developing and maintaining the standards.
I do not rule out one company building a starter network and growing substantially from there. I just do not think that the design choices that are best for the company’s shareholders in the short or medium term are the best choices for PRT as a long-term technology. PRT can have extremely positive effects on society and the planet and still be the basis for very profitable businesses, but there is no reason to believe that a system designed to be profitable and saleable today will resemble the design that has the most transformative potential. In particular, I think current designs have traded away flexibility in a rush to have a market-ready product. These designs have limitations in terms of speed, station layout, turning radius, scalability, safety, track pitch, and a host of other issues. Once deployed, these limitations become set. If they later become burdensome, there is not necessarily any way to remedy the situation while maintaining compatibility with the legacy system and its installed infrastructure.
P.S. I have added a Table of Contents. Now you can enjoy one-click access to all 110 posts in the archive! Also, there have been no malware alerts connected with this site per se; The one reader who has reported a problem apparently only gets a warning from the use of his “Google Alerts” redirect function to this site and not the site itself, so I’m not going to worry about it.
Posted by Dan at 10:38 PM