Sunday, October 25, 2009


This week I’m going to switch from low speed industrial and delivery to high-speed intercity travel. After all, once you modularize a PRT/PAT system, it opens up a lot of possibilities.

Here we have a high-speed tractor bogie, meant to act as an “engine” in the “railroad” sense of the word. By hooking one of these to a PRT bogie, (all done inside the shelter of the track) the PRT vehicle gets a big infusion of horsepower. This is directly analogous to adding engines to train cars, except in PRT the “cars” only need the engine for very high speeds. The cone part is an electromagnetic coupler with a data port in it. It uses the self-aligning qualities of a Morse taper, with magnetism and a limited travel universal joint to allow coupling and uncoupling via magnetic pole reversal. The pairs of enlarged guide wheels pivot to create a self-centering mechanism for the bogie. They are enlarged to retard the wear on both tire surface and wheel bearings that would come from high speeds and long distance travel. There are no provisions for steering shown, although they probably need them, to travel independently when needed. I would think that all small guide and steering wheels should be disengaged for high-speed travel though, because it would just wear them out for nothing. This idea would support the concept of removable, rubber mounted, guide-wheel running surfaces inside of the (municipal) track. (There are a number of other benefits to this idea) For high-speed sections these would just not be installed, leaving the smaller wheels with nothing to keep them spinning. Provisions would be required to get them up to speed before full reengagement, however.

The picture above shows how such “engines” could be used for high-speed intercity travel. Whereas the first pictures only showed the part that resides inside of the track, this picture shows an aerodynamic drag reducing “shell” that hangs down. (in blue and gray). As vehicles reach the end of the municipal track, “engines” fall in behind each of them until the system decides on a logical end point to the train. This “ad-hoc” monorail train can now travel at speeds that would be impossible for the PRT vehicles alone. Upon reaching the destination city, the train breaks apart, the PRT vehicles continue to their respective destinations, and the engines make a big U-turn and line up for a return trip. Such a scheme could (and, eventually, probably should) employ Meglev, (once public funds are as available for track as they are for roads) and I would shy away from any design commitments that unnecessarily preclude this eventuality.

Lastly, note that I have numbered my posts. Eventually I will include an index, since the vast majority of readers have found this site relatively recently.

Saturday, October 17, 2009

55> Chasing Trucks

I found myself following a beer delivery truck the other day, and when they pulled into a parking lot, my reporter’s instincts kicked in. My suspicions proved well founded. First I asked the driver (who had a helper) about the usual route. It turns out they had been on the road for 8 hours, since 6 AM. It was 2 PM, and they weren’t done yet. They told me that they intended to deliver for another couple of hours, and worked partially on commission. I asked them where they were working from and they indicated that they were about 20 miles from their home base. This was their section of the city. When I told them I was a blogger, writing about efficiency of delivery, the driver informed me that “Burp Brewing Co.” also had smaller trucks, which they used for lesser customers, like small restaurants, especially those with limited parking or maneuvering space for big trucks. (The truck he was driving, he informed me, could hold a thousand cases, somewhat more than he would deliver that day, and had been loaded in about 20 minutes.)

So there you have it. It can be said that his remaining cases had been on the road for at least eight hours to be moved 20 miles. (32km) That’s 2.5 mph. (average delivery speed = 4 mph, or 6.4km/h) Meanwhile two people are driving around in a huge, mostly empty, gas sucking truck. They will finish their day by driving the empty truck back 20 miles, a complete waste of time and machinery, where the truck just takes up space for other 14 hrs. before returning to duty. I would be surprised if the cost of the truck, insurance, space for storage, fuel, men, etc. is under $75 per hour, or $750.00 per day. If one assumes 10 hrs. for 1000 cases, that’s 75 cents on each and every case. “Burp Brewing Company” sells tens of thousands of cases a day.

This strikes me as directly analogous to problems with various forms of mass transit. The vehicles, buses for instance, must travel a large percentage of their routes nearly empty, and the many stops along the way create maddeningly slow commute times. Unfortunately, decision-makers tend to drive cars, so these inefficiencies are easy to overlook. The mother of non-invention is non-need. (Wouldn’t you love to make transit authority people commute everyday on the systems they manage?) Anyway this is not the case with commercial deliveries. Here decision-makers can make huge bonuses from incremental profit increases. A supermarket, for example, with a track running right into the back of the store could enjoy a substantial competitive advantage over stores that were not so connected.

When the Internet was first created, it was a limited network of limited importance. As businesses of all sorts started leveraging the technology, it became increasingly essential to be connected, just to remain competitive. Soon there were new business models that no one had previously imagined. I believe that the marriage of cheap computers, smart motors, and network communications is setting the stage for a transportation revolution that is far bigger than many, including many PRT advocates, presently (buuurrrp…) comprehend.

Sunday, October 11, 2009

54> SMARTS prt. 2

In the last post I introduced a catchy little acronym, SMARTS. (Small-scale Modularized Automated Rail Transport System) I’m not sure I like it, but it represents what I think is a good idea, the adoption of some open standards that others can build upon.

As I see it, the principle barrier that all PRT companies face is skepticism. Who can blame city planners and transit officials? The would-be companies come to the table with claims that they can build vehicles profitably, can build city infrastructure, including bridge-like track segments, can coordinate street traffic while utilities are being re-routed, negotiate the acquisition of right-of-way where needed, create a control system for these vehicles that is safe, build stations, maintain the fleet, collect tolls, etc.
“Gee that sounds like really fascinating technology,” Transit officials say, “Let me run it up the flagpole, and I’ll get back to you…”

One way to gain the confidence of customers is to have established standards and an independent standards body. After all, you need a license to practice medicine or even do plumbing. Anyone, however, can call himself a PRT provider. Standards creation is made difficult, however, by the fact that there are so many versions of what PRT should look like. I would hope that many of these providers would reconsider the highly proprietary nature their designs. Apple computer may have survived having it’s own standard, but that is certainly the exception rather than the rule.

I cannot champion all designs at once, and so I will concentrate on my own favorite, hanging designs, and more specifically the track, which is the part that needs standardizing most. This is because PRT companies might come and go, and vehicles will wear out, but the track is a very long-term investment. Even removal would be expensive. Cities need a “plan B”. Making a standardized, non-proprietary track that is cheap, simple and as versatile as possible seems like a worthy goal.

Here you see in the foreground the basic track shape I have shown previously. Just scroll down to my June 26th and July 16th posts for reference. I had mentioned in my last post that there could be various types of specialized track, such as low profile or industrial configurations that could extend the usefulness of PRT track. As long as there is some standardization, especially the slot width, there are many potentially useful configurations.

First, note that the track here is simple angle steel. It is shown as discontinuous so that it may be demonstrated that travel can be accomplished on a single side. The light brown hangers are produced from simple steel plate by a CNC flame-cutting machine. In other words, anyone can produce such track for little more than the weight cost of steel. For anyone who wondered, now you can see why my PRT track design has those hollow running surfaces. It is for flexibility in the support and steel thickness choices.

The picture above shows how simple a slower, more limited-range bogie may be. There are two aspects in particular which are not very practical in a PRT bogie that may be used here. One is the rims on the drive wheels (green), which hold the bogie in the track like a traditional railroad car. With high speeds, continuous use and quiet rubber wheels, these flanges would wear out. An alternative, shown here in violet, is guide wheels that are small enough to fit in the slot. In PRT, such wheels would spin over 5000 rpm, and would be too prone to heating and wear. Here I have redundantly included both of these slow speed options in a single bogie, for illustration purposes. Either would be OK for the occasional cross-town trip at reasonable speeds. Also note that there are no upper guide wheels, either for steering (blue) or centering. (violet) This is because this bogie is not designed to withstand the twisting torque of low-slung heavy loads on high-speed turns.

It can be seen that for companies to move goods around a factory, sky-hook style, is quite easy and cheap. It is not necessary to build full PRT track around the warehouse. Such a system could replace forklifts and conveyor systems, adding floor space. Goods could be moved between warehouses or to stores, increasing the usefulness of PRT track, especially at night. What is lacking, of course, is the software, which would be essentially the same as for PRT.

When we ask for taxpayer or investor money to build a network, that network should be very, very useful. Having certain key dimensions and construction details standardized just makes sense for everyone. An easy-to-remember acronym like SMARTS can’t hurt either.

Monday, October 5, 2009


I have been witness to the worst foliage season in recent New England history. It has rained almost every single day I have been here, and just been dark and cloudy the rest of the time. This has led to lots of time in the cabin, and I have had plenty of time to think, especially about the things the cabin lacks, like unending water and electricity and gas. It occurred to me that once upon a time, all water and fuel had to be delivered in person. This, in turn, got me to think about PRT as a pipeline, much like a utility. Actually I was mostly thinking about freight. Has anyone really analyzed what automated delivery would do for the world?

I personally believe that the big story here might not be, so much, PRT per se, but rather the automatic aggregation, transportation and distribution of physical objects, much like a the utilities I am presently lacking. Consider electricity from a variety of sources; wind, coal, hydroelectric, etc. It is mixed in the wires and sent out only where needed, where it is measured out into exactly what the end users require, where and when they need it. The utility can just read the meters and send out the bills. Isn’t PRT really the evolution of transportation into a similar model, except with people?

I have been hard at work trying to imagine a system that would work for people, mail, cases of cola, etc., and I’ve come to the conclusion that “one size” does not “fit all.” at least not with vehicles or their bogies. That is not exactly true with the track, however. I believe that a track design standard could be established that could accommodate various bogie styles and functions. In this approach the system would be highly modularized. Bogies would reside inside the track and various carriage styles for numerous functions would “snap” on. We could call it something like Small-scale Modularized Automated Rail Transport System. (That’s right. I invented SMARTS.)

I see something like four flavors of track, where for example, a PRT “pod” would be precluded from track that was primarily industrial, (it might allow extreme maneuverability, using super tight radii and cog technology for vertical travel) but the industrial bogie might use a public guideway. (Perhaps late at night) There could be a low speed, low profile, indoor (shroudless) track that would be for bogies that don’t require upper guide wheels, (too slow) but can be hug between the floors of buildings. There could be a very high-speed long distance variety, although I do not see it as being much different than ordinary PRT track, although the bogies would obviously be built for speed. (unless it’s fitted with Inductrack or something)

I will be posting more on this in the future, but for now, I am still out of town, and my laptop is ailing. (It crashed four times writing this, and won’t even recognize a thumb drive anymore) I will therefore get this posted, while this little library is open and this darn thing still works. That’s all from rainy NH.