They stopped using them 50 years ago.
The concepts behind the drop-offs and the pick-ups are basically the same.
This is nothing more than an elevated rail system and using a linear braking system to accelerate the stationary vehicle. Beyond that, we're talking simply precision and as the concept has yet to be implemented, the Chinese are no way more advanced with the concept than 50 years ago.
For all intent this is a worse design than having a tandem acceleration system in the trains and allowing the slip-car to simply accelerate itself to rejoin the express. You wouldn't even have to redesign your fleet, you'd only have to implement it in the slip-cars initially for the concept to work.
Anyone know what made the railway companies less competitive? I had always assumed that since they each had a monopoly over the tracks in each region, they had no real incentives to innovate.
As for Boston to Toronto I have done it many times the past two years before giving driving a try so I know how much time it actually takes. Door to door it was within a half hour of total traveling time, ton cheaper, real food, and the security at the boarder was not stupid. Driving I can go there whenever I want without needing to plans weeks in advance, adding another last minute person isn't a $2000 plane ticket, and I can change my return home plans on a whim. And as a bonus when I rent a cars I have been able to try out different models which I personally very much enjoy.
Each "car" holds just 2-4 people. they run on the tracks and switch on and off at the right stops. Very granular.
But still like a train in that you have tracks and power from the tracks. There is no conductor then, so everything would have to be computer controlled.
So picture parallel tracks with a merge-point somewhere ahead (or a few, in case one doesn't work). You've gotta split the train, merge in the new car, and merge it all back together, at moderately high speeds. Not much of a fun engineering challenge, methinks. The top-car probably makes more sense in this case. At low speeds, where all cars can be the same shape, certainly. Just remove / add to the front / end as needed.
My favorite design of PRT was always SkyTran, featured in a Popular Science or Popular Mechanics magazine years ago: http://www.skytran.net/phpsite/home/Home%20Intro.php
Real world engineering issues aside, my gut feeling was that a suspended/hanging pod would offer more stability and ability to accelerate than a traditional pod resting on top of tracks. If the pod could swing back and forth, acceleration and deceleration would push riders down into their seats rather than back or forward toward the windshield.
The Big Bad Wolf and Batman roller coasters come to mind. :)
This whole concept is insane. It would only work with pre-packaged cargo.
There is ample time as people are loading onto the slip coach to discover that the train needs to stop, although I think in practice this would never happen (the train operators would never be surprised by a large number of people trying to get off all at once).