Blade Runner road/rail freight/passenger transport

[Overmod]

Note on flywheels: The University of Texas 'megagenerator' uses a relatively small rotating mass, storing energy at a much higher rotational speed (which is a better way to do this if you're using microturbine drive and electric transmission). As of mid-April, they were reporting significant problems in their attempt to make this technology robust enough for practical rail application, although specifics are still proprietary. This is almost certainly the approach that would be used for railroad use of flywheel storage.

In particular, the UT project draws on the experience of the French and others in high-speed rail applications. There, very high instantaneous ratings are needed to operate at high speed on the very steep grades of the new TGV lines and equivalents (8 to 10 percent) -- this requires 25kV electrification and no underfloor power cabling, etc. in the French trains that operate such services. A non-electric locomotive for high-speed service would require a short-term energy source of similar magnitude, and it makes little sense to design a locomotive's engine to source that kind of power directly. The energy release rate of most cost-effective batteries is too slow, and the low breakdown voltage of supercapacitors requires very large arrays to give the necessary capacity and effective wattage needed for locomotive-class drives. It pays to remember that the UT flywheel generator is NOT intended as an energy-storage device for steady over-the-road operation, nor is it optimized for dynamic braking, although its design can be rather easily adapted to fulfill those functions if that is desirable. (As a detail, the use of hydrogen as a blanket in the generator, and as coolant for the generator's windings, makes good sense, imho much better sense than using hydrogen as a direct power source either through combustion in a heat engine or in fuel cells.)

[Overmod]

Principal issue with Blade-Runner like designs is that you have all the problems and capital cost of separately-powered road vehicles, vs. something like RoadRailer where minimum tare weight accomplishes the job. People who remember Flexi-Van may remember the problems with the earliest implementations, which required specialized underframes and tractors with special poles.

Note that a Blade Runner equivalent to a 10-wheel straight truck (of the kind that articulates with an 8-wheel trailer to form a hinged equivalent of a long 18-wheel van) can be used to pull some fairly large number of 'ordinary' RoadRailers for services that don't demand the power of even a small conventional railroad locomotive. The problems encountered with rubber-tired rail vehicles in the '30s and '40s (e.g. with Budd-Michelin railcars) have largely been solved with modern tire technology, and of course a modern multispeed truck transmission and modern (e.g. DDEC) engine can be capable of substantial starting TE coupled with good high-speed 'horsepower'.

Single big problem, as I see it? FRA regs requiring 800K lb. buff and draft strength. Put this into a truck chassis and you're talking considerable tare-weight increase. Laws can be changed to get around this -- and it would help light railcar design very greatly if that happened -- but I wouldn't look for that to happen soon with our current legal penchant to sue the hell out of railroad-connected things.

Don't be looking for modular trailers for passengers, or even modified buses with flanged adapters. The added cost and weight of the conversion equipment destroys any conceivable operating economy derived from railborne operation in almost any case, and I find it doubtful that a market for high-speed operation of such vehicles would exist. Lightweight trains (some, in fact, explicitly using bus bodies) failed miserably to catch on in the Fifties, and (TALGO in the Pacific Northwest aside) have limited application here.

tomtrain, consider hydrogen to be an 'energy carrier' rather than a fuel in the conventional sense. It is effective only as a means of reducing emissions at the point of combustion; the *overall* economy of even advanced hydrogen cycles is somewhat low. This may change for the better if some of the methods of dissociating water using incident sunlight turn out to be practical, but I wouldn't wait for it.

One principal 'advantage' of hydrogen cycle is that the fuel can be made in bulky and heavy stationary plants, then transported to the point of eventual combustion. In this respect, hydrogen is a somewhat better carrier than electricity, which must essentially be consumed in direct proportion to the amount generated over any substantial time. Some of the exotic fuel cycles under consideration at present, such as use of pure oxygen and CO2 recovery for clean coal combustion, can be used to generate non-electric-vehicle power if an appropriate carrier is provided (and incidentally provide the rather high level of CO scrubbing needed to keep many fuel-cell designs from being poisoned)

In my opinion, however, synthesized hydrocarbon (or hydroxycarbon) fuel represents a much better carrier solution than does hydrogen per se. I can go into great detail off-list on this.

[Anonymous]

Looks like a big Hi-Rail truck to me. Sounds like it will have all the problems that they have too. And if there isn't four rail wheels on the tractor unit how will it stay on the track? I used to run Hi-Rail equipment all the time about ten years ago. You couldn't get me to run or ride this thing for any amount of money.

[Anonymous]

Looks like a big Hi-Rail truck to me. Sounds like it will have all the problems that they have too. And if there isn't four rail wheels on the tractor unit how will it stay on the track? I used to run Hi-Rail equipment all the time about ten years ago. You couldn't get me to run or ride this thing for any amount of money.

[Anonymous]

Hugh, thanks for your response.

Regarding fly wheels, years ago one was tested on a transit car that toured various cities in the U.S. It was either a failure or its other features were incorporated separately into other designs. Furthermore, years ago there was an article in Scientific American where some of the problems with fly wheels were addressed. The mass was placed at the outer edge and the materials proposed where relatively light weight. Moreover, being composites a catastrophic failure would not require as much sheilding due to the tendency to unravel into relatively light weight pieces rather than a massive projectile breaking loose and striking the enclosure. Regarding the ability to destablize a vehicle - on a rail unit the fly wheels could be put on in pairs with counter rotations. Of course, they would have to be powered up and tapped in tandem.

With regards to the ceramic coatings of combusion chambers engines, I view the coating as both a problem in manufacturing (meeting precise dimensions) and causing excess friction. The temperatures these engines would run at would preclude all but the silicone liquids. From experience in other research I know that many would degrade at much lower temperatures. Another problem is that these fluids are extemely viscous, hence, what lubricant can be used on warm up? This could be problematic too if we wished to shut down when not is use.

Regarding stripping the excess energy content: as with any engine input/output it would be a trade off with exhaust tubing diameter size to limit back pressure. Regarding thermodynamic modeling of maximum theoreticlal efficiency - I am well aware of the limits. Nonetheless, we are talking about an exhaust in the region of 1000 degrees certainly (probably f.) cannot be released without cooling. Turbocharging strictly from the exhaust is probably not the best use, given the lag time, however, some effort should be made to use the exhaust gases. There are other options beside gaining mechanical engergy, e.g. preheating and presurizing air intake.

With all the talk, in this country at least, about fuel cells for cars. It is much more rational to start with small scale utilty power plants and backup power for larger institutions, e.g. hospitals. When fuel cells could go mobile, it would seem to me wiser to consider railway power units. Right now this appears too far in the future to be of any near term use.

One issue you kept bringing up was added weight, which I do not think is quite an impediment as you imply. In the U.S. freight units are loaded with excess sand or extra metal to add to their traction.

Sorry for the excess verbage, but I think despite railway's fear of the new the changes are long overdue.

Again thanks the points you raised.

[eastside]

Basically, isn't this the same concept used by engines drawing power from catenaries and third-rails? When they slow the engines become generators, converting kinetic energy into electricity for use by other units on-line. I've seen very little about how efficient or prevalent this practice was in the US. I believe the CStP&M "Little Joes" employed this technique.

[Hugh Jampton]

The problem with flywheels is their size relative to the amount of energy they can store. The energy is proportional to the mass and the rotational speed. The maximum speed is limited by the strength of the material to withstand the "centrifugal" force. usually they have to be encased in a very very strong (and heavy) housing in case the flywheel does burst. On a moving vehicle the gyroscopic effect of a large mass might be enough to derail a train when it enters a sharp curve. Bristol in the UK has a prototype flywheel tram (Parry People Mover) but it is very slow and only runs on a few hundred yards of track.

Ceramic materials are currently being developed, but ceramics are very brittle and do not function very well under tensile loads. Anyway, most of the heat generated in an engine comes from the heat of combustion and not from friction of the moving parts.

The laws of Thermodynamics state that there is only so much energy that can be recovered from the heat of the exhaust gases. If you add too much load on turbos by adding generators and the like then you increase the the resistance that the gases encounter as they leave the engine. This reduces engine efficiency because the pressure in the exhaust manifold is higher. Plus a larger mass means that the turbo will take longer to react to changes in gas flow (think old ALCOs)

Batteries are also not very efficient, and they are similarly big and heavy. There are some people trying to develop so-called super-capacitors which are lighter and can store more energy per pound than batteries.

Many forward thinking technologies are being used, or tried in the rail environment, but railroads tend to be very conservative when it comes to this sort of thing. i.e. the standard processor in a computer based interlocking is still a 486.


p.s. welcome to the forums,, I hope you find them interesting and enjoyable.

[Anonymous]

I was about to post the same link, however, I also wanted to ask: while history (e.g. steam engines and obsolete technology is of interest) even the current technology seems to be lagging in the U.S. Why hasn't most of the current motive power not employ any energy storage devices? For example, why not have dynamic breaking that stores power in a fly wheel for tapping for latter acceleration? What about ceramic coating of internal engine surfaces to either lower efforts in engine cooling or its elimination? Moreover, suppose the latter where used, the engine horse power could be lowered by also tapping and draining the energy content of the very high temperature exhaust. Suggestions: very high ratio turbo charging, driving fly wheels and at least powering a generator to store partially as chemicalicaly convertable power in batteries.

Steel rail and rails alone with lower friction will not suffice even though still inherently more efficient than the competition. Fuel costs are now on a continuous rising trend unless significant savings are soon instituted or other non-fossil fuel production developed.

Steam engines are impressive, as are some diesel units, but I would rather not put up with their environmental damage and health side effects inflicted.

When is Trains Magazine going to show some real interest in more forward looking technology?

[Anonymous]

Blade Runner is a truck with rail wheels. On rail it has 1/5 the rolling resistence as on road but is free to drive from rail to road and back.

http://faculty.washington.edu/jbs/itrans/bladerunnerupdate.htm