Battery Powered Full Size Locomotive

[Overmod]

Yes, but what of the pervasive conquest of modern intermodal markets by the earthbound equivalent of the 'simple' and 'light' gas turbine, as called for by Professional Iconoclast John Kneiling for the integral trains?  There has been enormous improvement in small ceramic magnetic-bearing turboshaft engines -- why don't we see them anywhere much since the stillborn ALPS locomotive?

Yes, it would be nifty to go to all-electric, and by extension to high-energy-density battery electric.  But there are enormous capitalizations involved, some of them mutually competitive for scarce resources.  I do not doubt for a moment that hydrogen fuel-cell and hybrid traction batteries are complementary, not competitive modes, but some in the Canadian venture-capital field already have the blinders on that it has to be one or the other that 'wins'.

I do believe that we can build high-amperage devices for all the constituents of a dual-mode-lite system using renewables for fuel.  That is future-proof all the way to pervasive electrification.  Sourcing the necessary electrical-supply density is where I see the problems, even before what happens when governments start taxing BEV equipment preferentially... 

[gregc]

Overmod

You need large numbers of specialized charging devices, backed by high-amperage connections, to do the job of a much smaller number of tanks, transfer pumps, and hoses

that helps

but it seems to me, high amperage electrical devices replace mechanical devices requiring more maintanance and the need to transport fuel.

i think a reasonable comparision is the adoption of jet engines in aircraft -- poorer performance but less maintanance -- and ultimately the high performance technology of today

[Overmod]

gregc

having a hard time following your presumptions

You need large numbers of specialized charging devices, backed by high-amperage connections, to do the job of a much smaller number of tanks, transfer pumps, and hoses.

Naturally a 'better' solution involves dual-mode-lite recharging the traction battery as blended draw when under wire/on third rail.  Much of the objection to 50kV electrification is how you handle the many overhead obstructions that give inadequate clearance.  With a reserve traction battery in the consist there is no difficulty making power discontinuous for even fairly long gaps... something  I am surprised hasn't been exploited in model railroading as a combination of dead-rail keep-alives to get rid of weird reversing loop and switch-construction wiring woes.

Of course in the long years to get to pervasive "enough" advantages of OHLE you still get all the desired bang for the buck out of fueled dual-mode-lite, with locomotives that Just Work as expected wherever you run them.

[gregc]

Take this simple quiz: where in modern railroading does that make any operational sense?  It is as dumb as a 9000hp PRR V1 with a water rate yielding less than 100 miles range without stopping...

?   its just being evaluated

... of course there would be more than one charging station if this type of loco were put into regualr service; presumably where diesel fuel is available and these locos are run

having a hard time following your presumptions

[Overmod]

gregc

...not sure what you're suggesting?

That without a great many comparatively expensive charging stations, and reasonably specialized operating 'use cases', a pure BEV use of the FLXdrive locomotive is ridiculously limited. It in fact represents just the kind of exaggeration seen in many hybrid designs that claim 'pure electric operation' -- for 25 to 40 miles range, slamming the battery through voltage-to-voltage converters for the last 15 or so.

... looks like there only one charging facility in Stockton, Ca.   They claim 30-40 min operation at full 4400 HP.

Take this simple quiz: where in modern railroading does that make any operational sense?  It is as dumb as a 9000hp PRR V1 with a water rate yielding less than 100 miles range without stopping...

On the other hand, that same MW/h capacity neatly assists in accelerating a consist faster, or with less fuel mass consumed by the hybrid's engines or fuel cells, or with lower pollution.

If it runs out of charge during a run, they simply don't account for those legs during the evaluation.

If it runs out of charge it turns into an expensive road failure.  One that almost certainly will have to be towed home instead of field-charged if operated 'solo'.

On the other hand if operated as a road slug 'with benefits' you can use the charge in the battery as you see fit, to cut fuel cost and emission, or happily charge it as desired when idling or running -- it will always work as some form of practical locomotive power.

not exactly sure you mean by mega charging?

"Megacharger" is Tesla's term for their truck-scale rapid charger (see Teslarati and similar sites for technical detail).  I would expect a sensible parallel charger for 'railroad' service to have its component elements sized similarly if only for OTS commonality in manufacture.

Don't diesel fuel tanks have multiple ports to shorten refueling time?

They can, although most of the time you see the multiple hoses feeding multiple units rather than one unit more rapidly.  I do have a picture of a very early facility (I think on Erie, actually during the war) that has multiple hoses per locomotive to speed refueling ... but that does not appear to have persisted.

Likewise you could do NASCAR-style pressure-assisted fueling with only minor changes to current nozzle and receptacle design and proper defoaming precautions... but no one spends the money.

presumably the FLXdrive battery can be segmented allowing multiple groups of cells to be charged independently and in parallel which would shorten charge time.

It is no NDA violation to say this is pretty obvious and self-evident.

 

For energy density of fuels vs. batteries, there is ample discussion and documentation on the Web, and this specific issue has been addressed with numbers in a couple of the Trains posts about battery locomotives.

 

Easy to figure out how long a 4400hp locomotive runs, or how far it is expected to go, before it needs fuel.  Easy to figure out from some of the fuel-tender experiments since the MATE discussions in the 1970s how much extended range from cheap welded tanks and a few more minutes pumping diesel is worth -- hint: achieving that extra capacity with just about any battery of reasonable energy density will be much more expensive.

Presumably there's room to at least double battery capacity

This was a point learned by the 'green locomotive' project -- there's plenty of room and weight-bearing capacity on a road slug to accommodate battery strings and cooling -- not so much if you have to shoehorn it into an engine already so heavy as to require six axles and fairly long frame length.  

[gregc]

Overmod

This is a consist in general railroad service, far from even one of the kind of 'megacharging' facility that would be required even single-headed to charge the size of traction battery represented by a practical FLXdrive in this service.  It makes no sense to use anything but grid power for the recharging;

not sure what you're suggesting?

of course the FLXdrive would need to be powered from the grid. looks like there only one charging facility in Stockton, Ca.   the claim 30-40 min operation at full 4400 HP.   if it runs out of charge during a run, they simply don't account for those legs during the evaluation.

route length 350 mi

not exactly sure you mean by mega charging?

don't diesel fuel tank have multiple ports to shorten refueling time.   presumably the FLXdrive battery can be segmented allowing multiple groups of cells to be charged independently and in parallel which would shorten charge time

Overmod

As noted, the energy density needed to replicate what's in a typical 4400hp diesel-electric's tank isn't cost-effective (or, really, safe enough) to provide as batteries

don't see where this is noted  (is this for 2.4M or 6MWh)

Wabtec is looking to build on these promising results with an even bigger and better version, upping the capacity to more than 6 MWh

presumably there's room to at least double battery capacity

but it looks like the available battery capacity is far from the energy capacity of 5000 gal capacity of a GE AC4400CW which is equivalent to 203 MWh/hr.   point understood

[Overmod]

gregc

you don't think the electric loco was recharged between runs and that charge wsa comparable to the amount of fuel in a diesel loco?

Frankly, no.  This is a consist in general railroad service, far from even one of the kind of 'megacharging' facility that would be required even single-headed to charge the size of traction battery represented by a practical FLXdrive in this service.  It makes no sense to use anything but grid power for the recharging; while a 'demonstrator' could use something like a truck-mounted generator to show how charging would work, the practical economics are not there.

As noted, the energy density needed to replicate what's in a typical 4400hp diesel-electric's tank isn't cost-effective (or, really, safe enough) to provide as batteries.  Makes better sense to size it as a hybrid, or as regenerative storage as lastspikemike was discussing, rather than pretend that road-locomotive BEVs as standalone power make current sense to manufacture.

Could you build such a thing? probably, as an engineering exercise.  I'm tempted to point out that if it were even remotely practical Elon Musk and RPS would have been all over it, and not in stealth mode either.  The Joule is an attempt at a pure BEV for a different niche, and it will be interesting to see if Progress has learned the necessary lessons so expensively taught by all the (uniformly unsuccessful) attempts that have gone before.

[gregc]

Overmod

The 11% is going to be saving of the three-unit consist over the test period, which is at least a month.  The amount of fuel involved in that length of operation of a three-unit consust dwarfs the nominal charge on a hybrid traction battery

you don't think the electric loco was recharged between runs and that charge wsa comparable to the amount of fuel in a diesel loco?

[Overmod]

gregc

presumably the Wabtec loco is fully charged before each run and they measure the charge consumed at the end of the run compared to the fuel consumed by the diesel loco. 

Doesn't quite work that way (although you could run it like a plug-in if you wanted).

The 11% is going to be saving of the three-unit consist over the test period, which is at least a month.  The amount of fuel involved in that length of operation of a three-unit consust dwarfs the nominal charge on a hybrid traction battery -- let alone the percentage of headroom over 'best long-term peak charge' for the strings or the battery architecture as a whole.

If the acceleration is fully and effectively blended (and I have no reason to surmise it is not attentively done) the train can 'start' with a relatively full charge and drain the traction battery diwn to an adequate level for subsequent dynamic-brake recovery.  Obviously an exception (as seen in the early Milwaukee Road regenerative testing) is if the train starts at considerable elevation or is facing meaningful downgrades after starting.  (The Carnegie-Mellon-style GIS/GPS tracking assists with predicting this).

Meanwhile, the 'other' thing about the battery is that it charges when the traction alternators in the two connected prime movers are load-regulated to the peak of the engine torque curve in the selected notch.  This can be done 'net' of unloading the engines briefly when throttling up to a higher governed rpm for lower transient emissions without significant loss of TE.  This was always an advantage for hybrid designs (I believe it was in the COMSOL modeling for the older GE 'green hybrid' a decade ago) but it becomes highly valuable for the 'extended' consist here.

The point of FLXdrive as a battery-only locomotive is, in my opinion, mostly hype -- it is not likely such a thing would be purchased 'new' for any branch or switching service outside of California or other subsidized/mandated context, and I regard BEV trucks and trains as something of a scam at best, but that doesn't keep me from working on them).  To me the point of a FLXdrive is as a full road slug 'plus' -- it has a cab and computers, so can as happily be MUed cabs-out with one unit as sandwiched with two, and of course can easily and cheaply be given adequate dual-mode-lite equipment when the industry wakes up regarding it.

[gregc]

Lastspikemike

The battery powered locomotive inserted into a standard diesel electric consist produced 11% reduction in fuel consumption of the consist. But it is not revealed where the initial charge came from. It's not rocket science to save fuel by including electric power from a battery pack. You're not saving anything useful. You're just adding electric power generated elsewhere maybe using different fuel. It's analogous to fitting an 11% larger fuel tank and claiming you got 11% better range

not sure what you misunderstood.   sound like your saying the Wabtec loco is a hybrid.  the article says

Wabtec's FLXdrive is described as the world's first 100-percent battery-powered locomotive

wasn't the experiment to compare the energy consumption of the conventional diesel locomotive and the FLXdrive locomotive consisted in the same train?

presumably the Wabtec loco is fully charged before each run and they measure the charge consumed at the end of the run compared to the fuel consumed by the diesel loco. 

 

[SeeYou190]

Colorado Ray

I recently bought a 2021 Tesla Model Y SUV.  The cost, not counting the full-self driving package, was similar to any luxury compact SUV.  <SNIP> The future is EVs whether you want to believe it or not.

As I mentioned earlier, I have a good friend that bought a Tesla SUV a few years ago, and he loves it. He has said it costs overall about half the amount to operate as his Toyota Tacoma did.

He has a generator and transfer switch attached to his house. He said that as an experiment he used the diesel generator to charge the Tesla, and it took about 4 gallons of fuel to get it done. That convinced him that the future efficiency is in electric vehicles.

Everyone I know with an Electric Car is happy with them. I will probably be in the market for one myself in a few years.

-Kevin

[gregc]

thanks very much

[snjroy]

gregc

i wish you would provide links to your claims.   i'd be interested in a better understanding

 

 

Lastspikemike

European cars and can recapture the same braking energy as any BEV or full hybrid.

 

 

 

 

Lastspikemike

Formula 1 is already using a version of this, not at a measly 48v though.

 

 

what do F-1 cars or any non-EV use the recaptured energy for?  they don't have electric motors, do they?

 

Hybrid vehicles have electric motors that assist the gas powered motor.  About F1, I assume Mike means the Electric F1.

Simon

[Colorado Ray]

Lastspikemike

 

 

Colorado Ray

 

 

Lastspikemike

 

For cars regenerative braking costs far more than the fuel it saves. The much touted fuel economy savings for hybrids or BEV are artificial and result from no fuel tax on the electric power. Plus several other boondoggle effects make BEV and hybrids look like they work economically, they do not. 

 

 

 

 

 

I've tried to stay on the sidelines, but have to comment on this.  

I recently bought a 2021 Tesla Model Y SUV.  The cost, not counting the full-self driving package, was similar to any luxury compact SUV.  The Tesla isn't eligible for the tax credit so that didn't factor into my purchase decision.

I'm averaging 250 W/mile.  My cooperative's energy demand rate is $0.0811/kWh.  So my energy cost per mile is $0.0275/mile.  My Jeep Cherokee averages 28 mpg.  The current price for regular unleaded at our nearest gas station is $2.95/gal.  The energy cost per mile is $0.1054/mile.  That's 380% higher than for the EV.  Additionally, EVs require no oil changes, belts, or brake replacements.  With regenerative braking, you seldom touch the brake so the original brakes are estimated to last the life of the car.  The only routine maintenance costs are wiper fluid, wiper blades and tires.

The future is EVs whether you want to believe it or not.

BTW, Tesla Autopilot has already saved my life.  Driving home on our country road includes a number of blind curves and hill crests.  I was using Autopilot at 45 mph going up one of the hills.  A car coming the other way suddenly crossed over the yellow line into my lane.  Autopilot swerved and drove onto the shoulder much much faster than I could have reacted.  Without Autopilot I would have had a head on collision.

Ray

 

 

 

 

Colorado has some of the lowest electricity prices in the US, half is coal fired and half the remainder is natural gas, a lot like here. That explains some of the cost savings. Your gasoline tax is lower than ours but still not zero. There is no mileage tax on electric power, yet. Are you calculating your electricity consumption just from what the car is telling you because that would not include power wasted in charging? The actual cost of running BEV should be calculated at the electric meter which is harder to do.

The Tesla autopilot didn't save your life but I'm glad you're ok. That's not a feature of an electric vehicle. AI automated driving is a very long way off (for important technical reasons) and when developed (not in my lifetime ) will be in all vehicles regardless of fuel source. The big problem with current dumb automated driving software is it just isn't very good. Compared to an average driver current automated driving systems look pretty effective but I can easily outdrive one, just for example. The illusion of competence comes from elimination of judgment time and physical reaction time, neither of which results from AI. The problem with current AI is that it is incapable of foresight. We don't know how to build a computer that can anticipate things that haven't happened yet, in  the way humans can, even infants have this capability while computers do not.

Leaving aside the usual list of BEV drawbacks (short range and long recharge times foremost among many) and your glossing over the battery pack replacement cost (all those belts and hoses will look pretty cheap and especially since modern cars don't need much servicing either) the main problems with widespread adoption of BEV are the same as face widespread adoption of electric power to replace fossil fuel power: storage costs and costs of increased generating capacity.

Regenerative braking on the other hand really does turn straw into gold by recovering energy from the system rather than wasting it. No additional power generation capacity is required. But the energy storage system, now that's complicated. On the other hand, if hybrid drive is feasible and can pay for itself you would expect locomotives and heavy goods trucks to be prime candidates for regenerative braking energy recovery. Racing cars not so much.

Here's the thing though: BEV pretty much have to include regenerative braking energy recovery to work economically but those systems are not unique to electric vehicles. Current 48v automotive electric systems are already standard on many European cars and can recapture the same braking energy as any BEV or full hybrid. A fairly small battery is required, about 50kg will do it, for a car because the accumulation and discharge cycles are relatively short. Formula 1 is already using a version of this, not at a measly 48v though. 

 

 

We'll just have to agree to disagree.  Change is always hard, but some of us adapt better than others.

The Tesla Autopilot did all the evasive action that prevented a head-on collision.  

BTW, I live in North Carolina, not Colorado, and a high percentage of our power is nuclear.

Back to the original discussion.  I expect that Wabtec's battery locomotive will find applications on lesser served rail lines.  The transcon routes will likely go with traditional catenary electric power.  You can take that to the bank.

Ray

[gregc]

i wish you would provide links to your claims.   i'd be interested in a better understanding

Lastspikemike

European cars and can recapture the same braking energy as any BEV or full hybrid.

Lastspikemike

Formula 1 is already using a version of this, not at a measly 48v though.

what do F-1 cars or any non-EV use the recaptured energy for?  they don't have electric motors, do they?

[Overmod]

gregc

what is "electric-level horsepower"?

Instantaneous horsepower available from external electrification (e.g. catenary/third rail with good substation support.

Are you suggesting the regenerative charging current is less than the load current or dynamic brake currents?

In my opinion, in a properly-designed system (some if the details of which I'm not discussing) the charging current can and will be at dynamic-brake levels; this of course will be higher than the load current for either engine or hybrid-battery supply.

Aren't charging systems designed to charge batteries in less time than it takes to drain them?

In general, yes.  Some much, much faster than others.  For external charging with parallel connections, as quick as typical non-pressurized hydrocarbon fueling; probably at least comparable to safe hydrogen fueling rate.

Aren't the railroads going to evaluate their claims in far more detail?

I'd bet on it. This is only a discussion for forum interest, to give lastspikemike a little more grounding to assess the point of hybrid locomotives.  On the other hand, current railroad management may not yet appreciate some of the ways "things are different" since 2012 when the idea was touted by GE in less well thought out form.

[Colorado Ray]

Lastspikemike

 

For cars regenerative braking costs far more than the fuel it saves. The much touted fuel economy savings for hybrids or BEV are artificial and result from no fuel tax on the electric power. Plus several other boondoggle effects make BEV and hybrids look like they work economically, they do not. 

 

 

I've tried to stay on the sidelines, but have to comment on this.  

I recently bought a 2021 Tesla Model Y SUV.  The cost, not counting the full-self driving package, was similar to any luxury compact SUV.  The Tesla isn't eligible for the tax credit so that didn't factor into my purchase decision.

I'm averaging 250 W/mile.  My cooperative's energy demand rate is $0.0811/kWh.  So my energy cost per mile is $0.0275/mile.  My Jeep Cherokee averages 28 mpg.  The current price for regular unleaded at our nearest gas station is $2.95/gal.  The energy cost per mile is $0.1054/mile.  That's 380% higher than for the EV.  Additionally, EVs require no oil changes, belts, or brake replacements.  With regenerative braking, you seldom touch the brake so the original brakes are estimated to last the life of the car.  The only routine maintenance costs are wiper fluid, wiper blades and tires.

The future is EVs whether you want to believe it or not.

BTW, Tesla Autopilot has already saved my life.  Driving home on our country road includes a number of blind curves and hill crests.  I was using Autopilot at 45 mph going up one of the hills.  A car coming the other way suddenly crossed over the yellow line into my lane.  Autopilot swerved and drove onto the shoulder much much faster than I could have reacted.  Without Autopilot I would have had a head on collision.

Ray

[Overmod]

gregc

Lastspikemike

 For cars regenerative braking costs far more than the fuel it saves.

reference?

It has been mentioned from time to time that recovering the full marginal cost of a full hybrid (or plug-in) from fuel savings alone can be an extended thing, highly sensitive to the price of fuel.  In the past, government incentives to buy hybrids or BEVs have subsidized much of the cost, but with the ending of these programs only the drop in factor prices, particularly assembled batteries, makes them affordable.

[gregc]

Lastspikemike

 For cars regenerative braking costs far more than the fuel it saves.

reference?

are you saying it takes more energy to put energy back into the batteries than the amount of energy put back into the batteries?

if your suggesting total fuel cost, this study suggests annual fuel cost of $485 for an electric vs $1117 for gas.

Overmod

and above just a few mph it would require electric-level horsepower to keep wheels 'just at the slipping point' whereas dynamic braking can reach those levels more easily.

what is "electric-level horsepower"?

are you suggesting the regenerative charging current is less than the load current or dynamic brake currents?   aren't charging systems designed to charge batteries in less time than it takes to drain them?

Overmod

I suspect WABTEC is claiming 11% lower fuel burn, without fancy adjustment for other forms of 'saving'.  Without knowing things like the number of ton-miles run I could only give you a back-of-the-envelope calculation,

aren't the railroads going to evaluate their claims in far more detail?

[Overmod]

gregc

locos accelerate a train but brakes on all the cars and locos are generally used to decelerate.

The point here is that, with good use of dynamic brakes and route knowledge, an engineer can control a train even over an undulating profile with speed restrictions without using the automatic air brake.  I recently followed a fairly long intermodal block from Collierville back through Germantown and East Memphis, and through all the curves and grades I did not hear him use the train brakes once -- it was all done with dynamic.

And where this is the case, regenerating the dynamic-brake power adds to the amount of fuel 'not consumed' (or the speed of acceleration from 'checks') as well as saving wear and trouble in using friction tread brakes and needing to think ahead with no graduated release.

I expect to see an actual engineering analysis (rather than marketing puffery) concerning that WABTEC 11% reasonably soon.   Some of the savings rely on effective blended power being used as a kind of counterpart of blended braking, to allow the engine fuel burn in a given notch to be lower than it would otherwise be, as well as allowing a lower notch for assisted operation.

Keep in mind that starting TE is more conservatively rated than 'decelerative effort' in proportional braking with wheelslide detection.  It is not a matter of 'different coefficient if friction' until you engage something like creep control at all speeds, and above just a few mph it would require electric-level horsepower to keep wheels 'just at the slipping point' whereas dynamic braking can reach those levels more easily.

I suspect WABTEC is claiming 11% lower fuel burn, without fancy adjustment for other forms of 'saving'.  Without knowing things like the number of ton-miles run I could only give you a back-of-the-envelope calculation, but with detail from the actual testing you would know the cost 'saving', and with detail from WABTEC about the FLXdrive cost per consist you could figure a break-even.  The RPS cost can be less because the strings are bought used, even net of the time and cost to renanufacture traction batteries out of them.

[gregc]

Lastspikemike

I am very, very sceptical that there's actually an 11% net recovery available given the physics.

why make a point of this?   what physics is assumed?   is it not good enough to justify this approach?   i think airlines would be exhuberant to see a 1% fuel reduction (see winglets).

locos accelerate a train but brakes on all the cars and locos are generally used to decelerate.  a rough estimate is if there are 100 cars, then loco braking is ~1/100 of the total braking (of course there's more than 1 loco and it is depends on weight).

i'll assume that while dynamic braking is more effective than friction brakes, there is a cost for the heat dissipators which i'll assume have limitations.

but if regenerative braking doesn't have these limitations and actually has a benefit wouldn't it be used more than conventional braking (i.e. brake pads on each car)?    would different braking techniques be used to maximize regenerative braking and could this account for the 11% or possibly greater savings?    would distributed power and braking become more interesting?

an assessment of the total mechanical friciton and less so aerodynamic drag would determine what is the maximum theoretical amount of energy that could be recovered and how far is 11% from it?

[Overmod]

Lastspikemike

The limits on regenerative braking recovery of kinetic energy for a diesel electric hybrid locomotive would be maximum tractive effort available at the drivewheels since that's the only available source of regenerative braking energy.

Yes, but you start by using the wrong expression and then assuming you're correct as you go along.

The maximum regenerative braking recovery is determined by the adhesion of the braked wheels, not by what the powertrain can develop using that adhesion.  There is less limit imposed on 'motoring' power development -- either by dynamic braking of DC motors or the methods used for synthesized AC -- both in terms of absolute braking torque and in the speed with which it can be modulated.  

Keep in mind that most of the kinetic energy of the train has gotten there through the adhesion of those same driving wheels, and much of any kinetic energy acquired gravitationally does not add disproportionally to the amount to be dynamically braked (and therefore to the proportion of dynamic braking that could be regeneratively captured).  It might be added that dynamic braking is not subject to brake-fade effects, so is applicable to gravitational-acceleration recovery to a greater extent than conventional friction braking could accommodate.

If the payload cars when also braked could be made to feed that power to the locomotive then more recovery is feasible.

Observe correct modern train handling.  You will see considerable use of dynamic alone to control train speed and state.  When you hear the node move, you are hearing transfer of momentum along the train; when slack runs out, the kinetic energy of the payload cars is 'fed directly' to the locomotives and hence becomes capable of being braked by them -- completely independent of any need for separate dynamic braking arrangements on the individual cars.

There have been discussions over the years involving distributed dynamic braking, and certainly the idea is technically feasible, even more so at present if ECP-style electric trainlining and distributed excitation control are available.  But for many situations in current real-world operation right down to slow-speed operation with adequate knowledge and time there isn't any need for special equipment on the cars at all.

I am very, very sceptical that there's actually an 11% net recovery available given the physics.

I suspect that when you actually know the physics involved, you will get the same results the actual physicists and engineers at GE observed with their test consist.  Unless GE's engineers are better liars and BSers than lawyers can be.  Heaven knows there are times in the past that they have been. 

Seriously: it wouldn't take much engineering to check the claim: we don't need to know the relative loss in dynamic braking, then in charge/discharge and internal resistance, then in transversion and blending to produce torque in motors, then apply formulae.  All the claim involves is 11% in operating expense, which here largely equates to fuel burn.  Measure the operating consumption over a month of known traffic, and compare to the equivalent in conventional power -- correcting for number of prime movers or IC-engine HP accordingly -- in comparable service producing comparable ton-miles.

Then figure out your potential error magnitude and compare it to adjustments in load, etc... if you want.

[Overmod]

Keep in mind that the high-acceleration performance is not representative of much railroad service.  A simple comparison is to look at throttle restrictions in current train handling.

The one place where very high draw, comparable to Tesla ludicrous+, would be necessary is in rapid acceleration to high speed.  This is seen in some commuter services, and is really best seen there with high-charge-rate regenerative braking (with its own engineering challenges to achieve with long-term reliability and cost-effectiveness); it is a feature of the RPS proposals... to an extent.  It is also seen in practical use of those "high-speed" 110mph corridors, where any practical time saving the riding public will notice or care about involves sustained operation at the high end... which implies rapid acceleration or recovery to that speed range.  

For most operation, though, cycling of this sort that reduces either the reliability or the effective life of the battery strings or cells may not be perceived as 'worth the gain'.  In part this would involve Acela-style marketing of the perception of higher speed or more exciting performance rather than actual time saving for the cost premium.  I'd like to see that work, for Amtrak's sake, but I have my doubts it will work in a corridor outside parts of the NEC.

For freight, the battery draw would be conducted analogous to permissible throttle notch for diesel-electrics.  You commonly see notch restrictions, on occasion pointlessly dictative or severe; I believe there are also a range of restrictions on the rate at which locomotive-notch advance governs actual power increase.  I would expect marginally faster acceleration from 'hybrid' power, but never drain outside that which the battery is demonstrated to source without internal damage.

I'm beginning to see a misconception about near-approximation to perpetual motion from regeneration.  That is not, and to my knowledge has never been, an engineering assumption either in regenerative braking for hybrids or for the practical economics of hybrid locomotives.  

The reported gain from the hybrid three-unit consist was reported in the original post -- circa 11%.  That is a substantial improvement over the baseline, and while I'm waiting for more detailed data regarding the performance, it seems conservative enough to be real.  From it we can certainly determine things like time to break-even, and additional opportunities from implementation of the 'enabling technology' in the sense that matters.  We can also extrapolate relatively easily to some of the alternatives this approach makes possible -- dual-mode-lite; hydrogen fuel-cells, additional use of road slugs in general consisting.  

 

[dehusman]

Also consider that what the high performance vehicles are doing is presenting a rapid high power drain on the batteries.

In a car, that only weighs a ton, that translates into high speed.  In a train, that high demand will be there every time to the train starts, the load on teh engine and the electrical consumption will be at peak loads.  Trains don't encounter peak loads at speed, they encounter them at low speeds when accelerating.

So, yes, the loading cycles on a high performance car are releavant, its just how that translates into the performance of the vehicle is different.

[Overmod]

gregc

why? cost of parts or labor?

The pravda is that electric locomotives don't need complex motor and generator maintenance, and don't need complicated electronic controls -- they just have electric motors that run and run and run and then get changed out quickly when necessary.  AC locomotives supposedly do speed control with transformer taps -- no moving parts or complicated relay logic or transition steps -- and we all know there are no moving parts in a transformer...

In practice there are issues that require locomotives, particularly those kept in regular service, to get regular shop attention.  The key is to make it quick and routine as possible, just as with steam service as it evolved at the end of NYC/N&W practice.

Where the fun comes in is when your purpose-built electric needs to have purpose-built parts that aren't cheaply or easily available, let alone well-remanufactured, in the aftermarket.

Note that the dual-mode-lite completely avoids this by having the entire drivetrain fully 'in common' with AC diesel-electrics.  One set of parts, one set of expertise, one expectation for hourly/instantaneous wear and stress expectation.  

In practice there are

[gregc]

Overmod

"Electric" railroading involves somewhat less maintenance than diesel-electric, but it is far from cheap.

why?   cost of parts or labor?

[Overmod]

gregc

there are other advantages to electric vehicles.   It looks like the marketplace is interested in higher performance: the Mach-E and F-150 Lightning.   E dragster may become a new class like the hemis

But remember that we're not looking at performance in railroading; we're looking at cost-effective transportation.  There are very few advantages in self-contained ludicrous+ mode style acceleration for railroading aside from considerations in flat switching that should, but so far seem not to, be significant in battery-enabled or 'genset' switcher design; we now have observed a 50-year history of attempts at 90-mph or faster freight, with examples like FedEx where high speed is required to make the economic business model work, with exactly zero long-term willingness for 'business' to pay the full required costs.  

Add in the anticipated reduction of lifetime and increased wear and maintenance from repeated heavy use of ludicrous+ acceleration, particularly if the battery operation is not correctly spot-cooled -- something I have not seen either tested or analytically discussed.  Not that I don't love it, just that the game has to be worth the candle especially in a modern financier-driven PSR version of railroading.

"Electric" railroading involves somewhat less maintenance than diesel-electric, but it is far from cheap.  Start cycling the batteries deep or hard and I suspect you'll see costs rise; once there are a few years on the batteries and the banks or strings start to need remanufacturing or component replacement, and we have more experience with charging infrastructure and its associated costs, we'll have a better idea of how much 'less' the cost over straight electrification 'with infrastructure' will be.

[gregc]

Lastspikemike

So, do we design and build electric cars and hybrid locomotives and heavy goods transport or not? Do we convert our mechanized agriculture to electric power?

I prefer that we leave these problems to the marketplace

there are other advantages to electric vehicles.   it looks like the marketplace is interested in higher performance: the Mach-E and F-150 Lightning.   E dragster may become a new class like the hemis

maintanance is also likely to be less for e-vehicles

as for railroads, will the energy recovered from braking possibly offset other inconveniences by reducing overall energy cost?

[Overmod]

Lastspikemike

For trains surely the challenge of regenerative braking is effective and efficient recovery of the kinetic energy from the payload?

The challenge is a bit more than with a road vehicle because of some of the characteristics of train handling.  If you are familiar with some of the discussions, theory, and practice of wayside storage you will have an idea of the forces and times involved; these scale in some ways to freight practice but have to be adjusted in others.

The range of rapid chemical-battery cycling is restricted in most cases where long service life is desired -- this is the origin of the 80-20 rule for lead-acid construction.  In practice this requires a larger capital expense for the overall battery structure, which translates into larger proportional size with increasing nominal capacity.  An implication is that the 'overhead' involve capacity for at least one full service stop in extended-range.  You may know by familiarity with 'charging algorithms' for hybrid cars that they reserve some of the service capacity for this eventuality when 'charging' during engine-assisted operation... there is similar discussion of apportioning 'headroom' in hybrid commuter operations where there is more rapid cycling between acceleration and deceleration with what can be substantial changes in live load.  Using the Carnegie-Mellon approach to combined GIS/GPS with knowledge of train resistance can fine-tune this 'as well as necessary' (with the retention of DB grids for 'emergency' assistance, which is assumed in the FLXdrive consist makeup)

If we assume -- as several on the Trains forum do -- that full emergency-braking time and distance are desirable for unanticipated braking, and then assume that full regenerative capture of as large a share of that braking effort, blended or not, is valuable, the rate of energy capture as well as cumulative magnitude takes on full importance.  There are maximum rates of charge that should not be exceeded.  It follows that simply cooling the chemical battery is not the only approach to facilitate faster charging; it should also be clear without violating NDAs what some of the proper methods will involve.

Note that proper braking involves a period of 'setting up the train' which usually involves either application of power or absorption of momentum in particular ways to get the slack consistently in, all without either shock or slip at the dynamic-brake contact patches.  In some cases this may involve very high momentary/peak charge transfer, including when going rapidly from motoring to dynamic... for which the system should be designed.  In a proper world this would be blended with brake modulation, but the implications there are more properly under NDA.

Incidentally, distributed magnetic track brakes became practical several years ago.  There are still valid arguments against their practical use, but they are really 'no more unsafe' than the current congeries of disparate technology used to implement PTC as mandated.  They will not work without very particular forms of energy charging, discharge, and control that use some of the same approaches as practical hybrid power.