Clever Chinese trains without stops at stations (concept) | Hacker News Reader

Clever Chinese trains without stops at stations (concept)

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42 pointssrgseg40 comments

This was invented and tested by the British over 150 years ago: http://en.wikipedia.org/wiki/Slip_coach

They stopped using them 50 years ago.

Slip coaches manage the drop-off, but not the pick-up.

To reverse the journey, the passengers would board the slip coach at the intermediate station, which would then form part of a local train to the next station on the line where the express was scheduled to stop, and coupled to the express train there to be taken to its destination.

The concepts behind the drop-offs and the pick-ups are basically the same.

You might watch the video. The train in this concept does not stop, unlike the case you describe above. It is certainly not "basically the same" unless you think this, slip-cars, car ferries, and modular cargo containers coming off a ship are all equivalent.

Yes, but this is not a dramatic new concept, it's a minor improvement in implementation because of decreased engineering costs and simply time.

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.

Whether it's a good concept, I don't much care. It is simply and obviously wrong to say it's the same as a slip car, just as it's simply and obviously wrong to say a motorcycle is the same as a draisienne. Whether it's "dramatic" enough a new concept for someone is not my concern.

The slip coach concept involves simply decoupling the last coach of the train so that it coasts into the station, therefore there is no equivalent for pick-ups - you can't just couple a coach to a fast moving train.

Why not?

Physics.

"In an era when the railway companies were highly competitive, they strove to keep journey times as short as possible, avoiding intermediate stops wherever possible".

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.

In the US, air travel made rail obsolete. For long distances (>500 miles) rail just can't compete with air. The was one of the main points in the book "Turbulent Skies: The History of Commercial Aviation" by T. A. Heppenheimer.

Another reason is that the freight companies own a vast majority of the rail tracks in the US which means freight trains get priority over passenger trains..

This only happened after the airlines stole most of the passenger traffic. By the 70s the rail vs flight curves had crossed and most passengers were on planes, after deregulation of the airlines the market for long-haul passenger carriage was owned by the airlines; the only thing left for railroads was freight and short-haul passenger traffic in populated corridors. When passengers were the bulk of the rail revenue stream the system was optimized in their favor, and when fright took over the conditions were inverted.

The airlines did not "steal" the passenger traffic... they offered something people wanted... a journey lasting hours instead of days.

I did not mean to imply that rail had any "right" to the passengers, just being a bit informal in the description. Faster transit was definitely the initial draw, but the implied status and luxury that early air travel provided was also important. The speed difference at the time was significant, but not as large as it is today -- NYC to Chicago was an overnight trip and you arrived blocks from the loop and in much better shape than you do today after enduring a similar trip.

Not any more. These days it is easier and faster for me to drive 500 miles from Boston to Toronto then to fly. Wonder if I could take a train...

You might have a case for Boston to NYC, but even with the 15 minute security check and the requirement to arrive 30 minutes before your flight leaves, you are still probably better off flying. In terms of time, that is.

The Boston to NYC trains are fantastic! I wouldn't fly between those two if I had the choice. Arrive in the city. Power plug on the train, tons of room. Real food. Cheap to do last minute. Not sure why anyone would want to fly between Boston any NYC these days.

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.

Wasn't this on HN a few weeks ago?

A couple months ago (among others):

http://news.ycombinator.com/item?id=1274655

Wouldn't this destroy a bullet train's aerodynamics?

Perhaps a better solution is to make trains more cell-based. (Think ATM.)

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.

I've thought of that as well, but you've got serious problems with air resistance (and associated vibration) at high speeds unless you've got contoured fronts and backs. So you'd have to drop and add cars in the middle of the train... added complexity and you'd need every unit to be powered independently (true, many are, but this would be a requirement).

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.

So how many people would end up having "fun" in these?

You may be thinking of something very much like Personal Rapid Transit: http://en.wikipedia.org/wiki/Personal_rapid_transit

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 would make for some quite spectacular accidents...

I can imagine some fussy grandmother disembarking all too slowly on the one car, and since the next one has to come in, no matter what, they'll have to launch it, and the old lady, out on to the tracks or risk crashing two of these cars together at extremely high speed.

This whole concept is insane. It would only work with pre-packaged cargo.

Looks like a pretty spectacular way to get yourself killed. Am I the only one thinking about what would happen if the slip coach didn't fully lock and then came loose while passengers were leaving or entering it from the main train?

It seems like it would be very easy for people to get on the wrong mini train and end up leaving at the wrong place, because it would likely take significantly more time to get ready for a disembark.

Seeing this reminded me of continuous elevators: http://www.youtube.com/watch?v=Zx3MHm9WjBE

what would happen if half of the train needs to disembark at the same time?

Then the train stops? This is intended to reduce the time to stop at small stations.

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).

They wouldn't be surprised that it was crammed uncomfortably full of people; that doesn't mean they'd do anything about it though.

what happens if some people still onboarding when next under-bullets comes?

Erm. What if you need to get off 3 stations down the line?

Then you don't take the express train. Just like now.

Sorry, I live in the middle of no where and don't really know anything about commuter trains.

Why the down votes? It's a serious question.

but how does one exit the train?!

The mini-train on top stops at the station, detaches from the main train, the doors open, and you exit by walking through the doors. Later, passengers board, the doors close, the mini-train waits for the next main train, and the mini-train attaches and off you go.

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