Gas-turbine HSR vs electric

I think this argument can be simplified into a statement that a gas-turbine driven passenger train is essentially the same thing as a very low flying airplane. It's fuel efficiencies and capacities are probably similar. The main difference is the train takes a route that costs $20 million? a mile to build, while the plane fly's through "free" air. To me, gas turbine high speed rail is of no benefit.

High Speed Rail's strategic advantage is that it is the only state of the art transportation infrastructure that can run off the electrical grid. France get's 70% of its electricity from nuclear powerplants, and those same powerplants power their rail network. Japan's situation is similar.

exactly right, except the "free" airway includes the air traffic control system - hundreds of radar stations, computer networks, etc, and of course the airports themselves.

An airplane has to keep itself flying, and having wings and control surfaces produces additional drag.

Even the fastest trains do not have to do that.

So that can make a difference, though I don't know how much it is.

Yes, air transport requires runways, radar, air traffic controllers, etc. But it's still cheaper than building a high speed rail infrastructure. That's why the U.S. has an airline infrastructure. If high speed rail were cheaper, then we'd have high speed rail. Cost drives EVERYTHING in the U.S.

Now, as the era of peak oil further takes hold, the U.S. will be stuck with two transportation infrastructures (Highway and Air) that the average American can less and less afford. They will not be growth industries. Then what will we do?

The air might be "free", but the ground support infrastructure needed to support commercial air travel is far from it. There's a word for a 767 landing on an unpaved landing strip -- it's called a "crash". I'm pretty sure you could build brand new (non-electrified) grade-separated tracks all the way from West Palm Beach to SR 528 (Cocoa Beach/Titusville) alongside I-95 on land already owned by FDOT for less than the construction cost of even the most minimal airport someone like Delta or JetBlue would ever voluntarily land one of their expensive jets at in a non-emergency.

As I put it to my (pilot) brother when he made the usual Glenn Beck remark about the supposedly infinite flexibility of planes to meet consumer demand by changing routes, "So... has your airline managed to get those new gates yet at O'Hare, LAX, or LaGuardia that it's been trying to get, well, forever? You mean you can't just buy a vacant lot and build some runways on it to satisfy the market demands of those eager consumers?" (at that point he was turning purple, but I think I made my point)

There's another key difference between a plane and an Acela-type train with power heads based on the JetTrain prototype -- you can stick a pantograph on the top, and run it from wires if they're available. This is hugely important, because it means you can incrementally deploy not only HSR (limping along on legacy tracks to serve additional destinations at dramatically reduced speeds off the shiny new HSR mainline during the early years), but electrification as well. The only reason why Bombardier didn't make the JetTrain tri-powered from the start was due to marketing -- they (or USDOT) didn't want to muddy their message that it didn't NEED wires to run. An Acela-type train with tri-powered JetTrain power heads could run with or without wires... that's something a plane will never, ever be able to do.

The truth is, it might not be cost-effective to run from turbine power forever, but in the real world, one thing is obvious: Florida voters are fickle, impatient, cheap, and self-centered. If they can't have HSR service in their own city, now, they won't support it anywhere. Keeping the initial deployment cost cheap is a perfect way to politically low-ball Florida -- build the tracks "everywhere" (well, serving 85% of the state's population), THEN sell the public on the benefits of electrification once people start to gripe about the operating costs. I can guarantee, if Florida tries to build no-compromise non-FRA fully-electrified HSR from Miami to Tampa, and starts with Tampa to Orlando as segment 1, tries to build Orlando to West Palm Beach as segment 2 (with plans to have riders south of that point take Tri-Rail to WPB and transfer), and plans to build West Palm Beach to Miami as segment 3, the program would get killed by the next governor or Senate before anyone even had a chance to break ground south of West Palm Beach.

THAT'S why Acela-type trainsets with JetTrain-type powerheads are so important. It's an insurance policy to ensure that even if the program gets killed before HSR is done all the way down to Miami, Florida will STILL be able to run trains at 150+mph from Tampa to West Palm Beach, then zigzag madly around Tri-Rail and the few remaining freight trains along SFRC at 110mph the remainder of the way south to Miami. Likewise, it makes it possible to sell the program to hostile voters by promising "near-HSR" service all the way to Jacksonville from day one (temporarily using FEC north of the point where I-95 and FEC cross paths by Ormond Beach), extend the tracks from Tampa to Naples to shore up more political support while the new HSR tracks are under construction south of West Palm Beach, then finish up the HSR tracks to Jacksonville, and continue them to Tallahassee, shortly thereafter. It even gives an excuse to hurry up and expedite the construction down to Miami and up to Jacksonville -- since the hourly operating costs of a turbine train are relatively constant regardless of speed, you can put a hard monetary value on the cost of that extra time spent running on non-HSR tracks and use it to make the new tracks look less expensive.

A few points based on your post, miamicanes:

miamicanes wrote:The air might be "free", but the ground support infrastructure needed to support commercial air travel is far from it. There's a word for a 767 landing on an unpaved landing strip -- it's called a "crash". I'm pretty sure you could build brand new (non-electrified) grade-separated tracks all the way from West Palm Beach to SR 528 (Cocoa Beach/Titusville) alongside I-95 on land already owned by FDOT for less than the construction cost of even the most minimal airport someone like Delta or JetBlue would ever voluntarily land one of their expensive jets at in a non-emergency.

As I put it to my (pilot) brother when he made the usual Glenn Beck remark about the supposedly infinite flexibility of planes to meet consumer demand by changing routes, "So... has your airline managed to get those new gates yet at O'Hare, LAX, or LaGuardia that it's been trying to get, well, forever? You mean you can't just buy a vacant lot and build some runways on it to satisfy the market demands of those eager consumers?" (at that point he was turning purple, but I think I made my point)

Very true, and that's why rail expansion projects are so important for mid-large feeder airports on rail lines (Gary for Chicago, or Fort Lauderdale for Miami, for instance.) Higher-speed rail increases the distance between which airports are practical - both Milwaukee for Chicago and Philadelphia for New York come to mind. And given high enough speed rail, you don't need the airport at all, freeing up even more capacity.

miamicanes wrote:There's another key difference between a plane and an Acela-type train with power heads based on the JetTrain prototype -- you can stick a pantograph on the top, and run it from wires if they're available. This is hugely important, because it means you can incrementally deploy not only HSR (limping along on legacy tracks to serve additional destinations at dramatically reduced speeds off the shiny new HSR mainline during the early years), but electrification as well. The only reason why Bombardier didn't make the JetTrain tri-powered from the start was due to marketing -- they (or USDOT) didn't want to muddy their message that it didn't NEED wires to run. An Acela-type train with tri-powered JetTrain power heads could run with or without wires... that's something a plane will never, ever be able to do.

The truth is, it might not be cost-effective to run from turbine power forever, but in the real world, one thing is obvious: Florida voters are fickle, impatient, cheap, and self-centered. If they can't have HSR service in their own city, now, they won't support it anywhere. Keeping the initial deployment cost cheap is a perfect way to politically low-ball Florida -- build the tracks "everywhere" (well, serving 85% of the state's population), THEN sell the public on the benefits of electrification once people start to gripe about the operating costs. I can guarantee, if Florida tries to build no-compromise non-FRA fully-electrified HSR from Miami to Tampa, and starts with Tampa to Orlando as segment 1, tries to build Orlando to West Palm Beach as segment 2 (with plans to have riders south of that point take Tri-Rail to WPB and transfer), and plans to build West Palm Beach to Miami as segment 3, the program would get killed by the next governor or Senate before anyone even had a chance to break ground south of West Palm Beach.

THAT'S why Acela-type trainsets with JetTrain-type powerheads are so important. It's an insurance policy to ensure that even if the program gets killed before HSR is done all the way down to Miami, Florida will STILL be able to run trains at 150+mph from Tampa to West Palm Beach, then zigzag madly around Tri-Rail and the few remaining freight trains along SFRC at 110mph the remainder of the way south to Miami. Likewise, it makes it possible to sell the program to hostile voters by promising "near-HSR" service all the way to Jacksonville from day one (temporarily using FEC north of the point where I-95 and FEC cross paths by Ormond Beach), extend the tracks from Tampa to Naples to shore up more political support while the new HSR tracks are under construction south of West Palm Beach, then finish up the HSR tracks to Jacksonville, and continue them to Tallahassee, shortly thereafter. It even gives an excuse to hurry up and expedite the construction down to Miami and up to Jacksonville -- since the hourly operating costs of a turbine train are relatively constant regardless of speed, you can put a hard monetary value on the cost of that extra time spent running on non-HSR tracks and use it to make the new tracks look less expensive.

See the NJ Transit saga of the ALP-45DP for more about why dual-power is so difficult, but essentially, high-voltage AC power is an entirely different beast from low-voltage DC. You need large, heavy transformers and much more sophisticated control equipment to run an AC train. Low-voltage DC requires no transformer and can use much simpler and cheaper control equipment, which is why the Turboliner and Turbo Train had a DC third-rail shoe for access to New York Penn. You could order your JetTrains to be turbine-electric, over-design them to take the weight of a heavy transformer instead of a lightweight turbine and mid-weight fuel tank, and have the components in a warehouse ready to quick-change... or you could buy new electric locomotives for your trains.

Other than that, I'd still stick with an diesel locomotive up to the HSR threshold - if a single E unit can pull 2-3 cars at 120 mph with 2,000 horsepower (EMD offered that gearing), we can certainly make a pair of 4,000 horsepower diesels do 125 mph with 6 cars. North of 125, I still think the electric's energy consumption, per-hour costs, lower maintenance cost and far better acceleration would outweigh a turbine's lighter weight, cheaper initial cost and lack of electrical infrastructure, BUT there may be a gray area for long-distance lines with few stops.

Quick note: by "tri-power", I don't mean differing catenary voltages. One aspect of the JetTrain that kind of got buried and overlooked by lots of people is the fact that it actually has TWO onboard diesel-fueled generators -- a turbine for high power, and a more conventional diesel generator for low power. From what I read, the low-power generator, when used in pairs of power heads flanking a typical Acela trainset, could run the train at speeds of up to around 30mph, although its primary purpose was to give the train electricity for things like lights and air conditioning while the train was in a station, so the turbines could be shut down and save fuel. The third power source I'm referring to is a pantograph (omitted from the prototype JetTrain, but entirely do-able, if not actually intended from the start by Bombardier's engineers) to enable it to run from overhead catenary wires without either the turbine or the conventional generator running when available.

In reality, as far as the electric traction motors were concerned, it would probably deal with a single voltage from three different power sources -- the turbine, the conventional generator, and the overhead wires.

your not going to fit all those options into anything approaching an acceptable weight for HSR .

MikeinNeb wrote:Yes, air transport requires runways, radar, air traffic controllers, etc. But it's still cheaper than building a high speed rail infrastructure. ...

Maintaining existing infrastucture vs. building new infrastructure?

Checking recent budget reports, the Federal Aviation Administration costs about $15 billion / year to run.

The US was far from the only nation to invest heavily in air-travel infrastructure in the 20th cy.; just about every other nation has built some. So I think that it was some difference in politics and institutional arrangements. US railroads weren't exactly loved by the politicians; they were heavily regulated, and they did not receive the government spending that roads and airports got. Only when they were on the verge of collapse did the politicians do anything to reverse that. I don't know what the story is about European railroads, but I have the impression that passenger railroading was declining there also until high-speed rail lines were built. Not enough to make an overall difference, but enough to make a difference where they ran.

David Benton wrote:your not going to fit all those options into anything approaching an acceptable weight for HSR .

A dual-electro-diesel has to haul fuel about (and it's a danger if there is a crash).

There is a lot of discussion about dual mode trains in Britain at present. The idea is to extend trains on to non-electrified tracks, such as Edinburgh to Aberdeen. In any case I think the Scottish government will electrify that line quite soon. The other line is London to Wales where the cheapskate government won't pay for electrics from Cardiff to Swansea. Or westward beyond Bristol to Penzance.

British Rail used to change locos, and I don 't see what's wrong with that. I used to experience it quite often and it never caused any problem to the passenger that I could detect. For example the train coming up from Reading would change locos at Coventry, in the platform.

MikeinNeb wrote:I think this argument can be simplified into a statement that a gas-turbine driven passenger train is essentially the same thing as a very low flying airplane. It's fuel efficiencies and capacities are probably similar.

Wrong on every level. There's a reason why you don't see jet liners cruising at low altitudes. The economics of low altitude flight are very poor

MikeinNeb wrote:High Speed Rail's strategic advantage is that it is the only state of the art transportation infrastructure that can run off the electrical grid. France get's 70% of its electricity from nuclear powerplants, and those same powerplants power their rail network. Japan's situation is similar.

And look at Japan's current situation? Talk about an environmental catastrophe!

goodnightjohnwayne wrote:
...

MikeinNeb wrote:High Speed Rail's strategic advantage is that it is the only state of the art transportation infrastructure that can run off the electrical grid. France get's 70% of its electricity from nuclear powerplants, and those same powerplants power their rail network. Japan's situation is similar.

And look at Japan's current situation? Talk about an environmental catastrophe!

implying that Japan's electric rail network is the reason they built nuclear power plants in earthquake zones ?
or that without nuclear plants electric railroads cant be contemplated?

The Gas Turbine on rail idea has been around and tried experimentally for sixty years. The high rpm/low torque output simply does not match traction needs no matter how much electronics, hydraulics or gearing is thrown at the problem. In the meanwhile, the humble diesel has become over 50% efficient and capable of running on a variety of fossil fuels including LNG at speeds well over 150mph.

There are definitely many reasons to consider (as Network Rail is doing) electro-diesel power in a high speed rail environment but that should be discussed in a thread unto itself.

> your not going to fit all those options into anything approaching an acceptable weight for HSR .

Remember, the JetTrain power head ALREADY had two of the power sources in the design from the start -- the conventional diesel engine used mainly (but not exclusively) to drive the generator for head end power (HEP), and the diesel turbine engine to drive the generator for high-speed operation. The only additional element for tri-power operation would be the pantograph, transformer, and switching mechanism. While I'm sure the added weight isn't zero, I find it hard to believe it would be a make-or-break difference -- especially when you factor in the flexibility it gives you to electrify one segment at a time. You don't need two completely independent power systems. Once you get the catenary voltage down to generator level, everything beyond that point can be shared by both.


>A dual-electro-diesel has to haul fuel about (and it's a danger if there is a crash).

And a pure diesel (turbine or otherwise) doesn't/isn't?


>British Rail used to change locos, and I don 't see what's wrong with that.

If only the engineers are involved, there's a time delay. I suspect that it takes a LOT longer to swap powerheads than it would take for a tri-powered JetTrain-type to just raise the pantograph once it reached the first station with overhead power and continue. I suspect it would also require the participation of a lot fewer expensive unionized workers than an powerhead swap would entail.


Example use case where trains can run from turbine, head end power (HEP), or pantograph:

Northbound train is in Miami, about to depart. Pantograph is up, because the HSR line is electrified between Miami and West Palm Beach to allow faster operation within a corridor that's HSR, but not quite ideal geometry and requires a bit of accelerating and braking to maximize speed.

Train reaches West Palm Beach station. HEP powered up. Pantograph lowered. Turbine powered up. Train departs north towards Orlando.

Train arrives at Orlando airport. Turbine shut down. Pantograph raised. HEP shut down. Train continues to International Drive and Disney on overhead power, because turbine power would be grossly inefficient with stops so close together.

Train arrives at Disney. HEP powed up. Pantograph lowered. Turbine powered up. Train runs the rest of the way to Tampa, then continues south to Naples.

-----

A few years down the line, a decision is made to electrify everything between West Palm Beach and Orlando, so trains now run from overhead wires all the way from Miami to Disney. Eventually, Disney-Tampa gets electrified, too.

------

At some point, the Saudi Royal Family gets violently overthrown by the Islamic People's Army, and overnight oil prices double. Within a matter of days, the Florida Senate passes an emergency bill funding electrification of the HSR line's remainder. It takes about a year and a half to finish the job, but looking back, at least Florida HAD the tracks in place, ready to electrify, with power heads that didn't need replacement to take advantage of the newly-electrified track. Compare that to the real-world scenario of a state that built one isolated, token 'demo' project at a time between two secondary cities. People in state #2 who were previously fond of criticizing Florida's trains as overweight, wasteful of fuel, and "stuck in the past" can enjoy their academically-pure train between Fooville and Barton, while Floridians can enjoy 150mph trains that are now 100% electrified, can probably be pushed up to 165 or 180mph with little more than regulatory approval at that point, and a network that can now be incrementally upgraded with lighter trains to allow 220+mph operations in the future.

Turbine trains are a technical solution to a very real political problem. At the end of the day, it's expensive to build brand new HSR passenger corridors, but if they're built alongside existing highway corridors on land already owned by the state, the cost can be kept relatively manageable as long as you're talking mostly about a place like Florida (no mountains, few hills, no earthquakes). In Florida's case, deferring electrification and using the savings to pay for additional tracks from Tampa to Naples would buy the votes of roughly 10% of the state's voters, but more importantly in pure political terms, it would buy the votes of roughly 18% of the state's Republican elected officials.

The Gas Turbine on rail idea has been around and tried experimentally for sixty years. The high rpm/low torque output simply does not match traction needs no matter how much electronics, hydraulics or gearing is thrown at the problem. In the meanwhile, the humble diesel has become over 50% efficient and capable of running on a variety of fossil fuels including LNG at speeds well over 150mph.

The problem you mention, though, is that every past attempt to use gas turbines has tried to use them as the ONLY power source. Turbines have a narrow range of efficient operation, and the more you deviate from it, the less efficient they become. The key to keeping turbine use viable is to isolate out the use cases where the train spends non-negligible amounts of time running within them, and find an alternative source of power to use in those situations.

Brand new HSR tracks across open countryside can be made flat and straight pretty easily. They're the golden use case for turbine generators.

Brand new HSR tracks through compromised alignments would be found almost entirely in dense urban areas -- areas that are relatively well-defined, finite, and probably have enough trains to justify electrification from day one. In areas that are electrified, where the turbine can be shut down and pantograph raised, the turbine's inefficiency is irrelevant.

110mph operation along tracks shared with freight is clearly where things get ugly, and where turbines are a waste for long-term long-distance operation. However, if you assume that any such operation is an extreme edge case that's just a temporary stopgap measure to enable direct service into areas where the new HSR tracks aren't finished or funded yet, it makes more sense. It would be stupid to go out and buy JetTrain powerheads for something like 3C in Ohio, or any scenario where the vast majority of revenue time won't be spent on real HSR tracks at speeds of 135mph or above.

Going WAY back to my earliest posts about hypothetical overnight Acela service between the NEC and Florida, Amtrak could deal with reduced-speed operations between DC and Florida by using three different power cars along the way -- conventional electric power heads between Boston and DC, high-powered diesel between DC and Jacksonville, and JetTrain the remainder of the way through Florida. Assuming, of course, that the cost of dealing with three sets of power heads and the crews to swap them in two locations didn't end up costing more than just sticking tri-powered JetTrain heads on the train, and running it in that configuration all the way from Boston to Miami. Personally, with the service upgrades Virginia and North Carolina are already aggressively making, I suspect that Amtrak would decide to just stick with catenary-capable JetTrain all the way, and the higher costs of operating it through South Carolina and Georgia would still be less than the cost of swapping engines along the way. Remember, Amtrak used to swap engines along the NEC because they HAD to -- electric couldn't operate without catenaries, and diesel couldn't run into New York's tunnels. It had nothing to do with dollars, and everything to do with logistics.