Amtrak Locomotive F69PHAC

[Railway Man]

Thanks -- that's very useful information.  I will have to mull it over and talk it around here in the office.  Care to speculate on when such technology might hit the operational threshold?

Interesting aside.  You alluded to public objection to catenary.  I was meeting on another topic with the director of planning for a major suburb of a large U.S. city a few weeks ago, and he mentioned that he was pleased that the transit system currently under design for his city would be using DMUs instead of EMUs, because "I've worked really hard to improve the visual appearance of this city and the overhead wires are awful."  I tried not to look astonished that someone would take the noise, air pollution, and lower reliability of DMU over EMU, and consider it a good trade for the visual intrusion of catenary!  It goes to show that people can have some very different value systems, and not to assume anything.

RWM 

 

[JT22CW]

NJT's GP40Ps, when NJT slide a HEP skid in the place of the steam gen. topped out at over 300,000 (lbs)

I don't know where you heard this, but that's not true whatsoever.  They wouldn't let anything with 75,000 pounds per axle out onto the railroad.  The ex-CNJ Geeps, like other passenger Geeps on other roads, max out at 268,000 pounds.

For the record, all of NJT's F40PH-2s were rebuilt into F40PH-2CATs (with Caterpillar HEP "pony motors") in the 90s.  (F40PH sans pony motor is 263,000 lbs.)

[JT22CW]

Amtrak's fleet isn't THAT old, but remember, no matter what they choose, to do they will be begging for money from the federal government

Wow, what a singular problem that other passenger rail does not experience.  Certainly, VIA Rail doesn't "beg for money" from Ottawa, nor commuter rail from their respective state governments, nor DB from Berlin, nor SNCF from Paris, nor JR from Tokyo (in spite of the "privatized" operation companies, the infrastructure is still subsidized).  How is it that Amtrak differs so markedly from these other passenger operators that they must have their own spotlight in spite of their needing to be funded just the same as they do?

I'm not sure I understand your point here. 

I'm sorry; I thought that I was being clear.  I'll spell it out once again, in not-so-sarcastic language:

• All of the railroads that are not Amtrak, that I had listed, all "beg for money" from their respective government(s).
• In the face of that, singling out Amtrak for special castigation over that same point is an unfair attack.

[chefjavier]

JT22CW:

We all know the truth about Amtrak.

[erikem]

Thanks -- that's very useful information.  I will have to mull it over and talk it around here in the office.  Care to speculate on when such technology might hit the operational threshold?

RWM was replying to comments about my suggestion for a hybrid commuter locomotive - and my apologies to him for taking so long to reply - had to mull over the answer a few days.

I suspect battery or capacitor technology may by ready in 5 to 10 years. If you're OK with the gas turbine route (i.e. a light prime mover allowing say 15 - 20 tons of batteries), the technology is available now - a lithium battery that can handle 500,000 charge/discharge cycles as long as the depth of discharge is limited to about 3% (may have the manufacturer's name at work) equivalent to about 4whr/kg (watt-hours per kilogram). Safe to say, the price on the locomotive would cause a pretty bad case of sticker shock. 

I'm basing my estimate by assuming that a B-B loco with a 3,000HP prime mover can accelerate its train at 1MPH/sec up to 20 MPH, that an extra 4,500KW from the battery should continue the 1MPH/sec rate to 60 MPH, followed by another 30 seconds of 4,500KW  from the battery to accelerate to 80+ MPH. This works out to 62.5kwhr or about 15 metric tons to keep the Li batteries in the long life operating regime.

The latest ultracaps from Maxwell are running 4 to 5whr/kg when completely discharged - we'd probably want to limit dischrage to 50% to keep the inverter input voltage from getting too low, and thus the cap bank weight works out to be 25 tons.  There are claims that the energy density could be raised to 40whr/kg, in which case the cap banks would weigh a bit under 3 tons - which is what Bill Farquhar of NCTD (now running commuter rail in Dallas) said was the weight of the dynamic braking system on the FP40's - which wouldn't be needed with a hybrid loco. We might see this in ten years. A 3 ton Li battery pack would work, but lifetime would be a few thousand cycles at most (too short).

An aside about the ultracaps - Oshkosh Truck is working on a hybrid off-road combat transport using a bank of ultracaps behind the cab. Testing is supposed to start in 2008.

My understanding is that GE's hybrid locomotive uses a sodium sulfur battery. It sounds like the battery is being optimized for energy density rather than power density. I also have no idea of what the trade-offs are for depth of discharge, peak power and number of cycles with this battery. I would guess that this battery would work in a turbine locomotive, but don't know if the technology can be pushed to get a useful life from a battery pack light enough for a diesel locomotive. The upsides are that the battery is being developed specifically for locomotive use and that both sodium and sulfur are abundant.

[da_kraut]

Hi,

this might be a silly suggestion but why not create a passenger locomotive with two diesel engines along the lines of the new gen set switch engines.   If a passenger engine has two 2000hp diesel engines only one might be required for 80 percent of the run they are on and the rest of the time the second diesel kicks in.   IT would certainly make things more efficient.

Frank 

[erikem]

Frank,

 Republic locomotive was proposing to do something close to what you suggested.

A couple of points. The first is that diesel engines throttle down well, you won't gain much in efficiency by shutting down one engine (an exception is where the second engine is HEP only during a layover). The second is that a hybrid would recover a lot of the energy normally wasted in braking.

The gist of what I was proposing was making a hybrid with a high short term power rating - something that would have some of the advantages of an electric passenger locomotive without having to string up wires. 

[Railway Man]

Thanks -- that's very useful information.  I will have to mull it over and talk it around here in the office.  Care to speculate on when such technology might hit the operational threshold?

RWM was replying to comments about my suggestion for a hybrid commuter locomotive - and my apologies to him for taking so long to reply - had to mull over the answer a few days.

I suspect battery or capacitor technology may by ready in 5 to 10 years. If you're OK with the gas turbine route (i.e. a light prime mover allowing say 15 - 20 tons of batteries), the technology is available now - a lithium battery that can handle 500,000 charge/discharge cycles as long as the depth of discharge is limited to about 3% (may have the manufacturer's name at work) equivalent to about 4whr/kg (watt-hours per kilogram). Safe to say, the price on the locomotive would cause a pretty bad case of sticker shock. 

I'm basing my estimate by assuming that a B-B loco with a 3,000HP prime mover can accelerate its train at 1MPH/sec up to 20 MPH, that an extra 4,500KW from the battery should continue the 1MPH/sec rate to 60 MPH, followed by another 30 seconds of 4,500KW  from the battery to accelerate to 80+ MPH. This works out to 62.5kwhr or about 15 metric tons to keep the Li batteries in the long life operating regime.

The latest ultracaps from Maxwell are running 4 to 5whr/kg when completely discharged - we'd probably want to limit dischrage to 50% to keep the inverter input voltage from getting too low, and thus the cap bank weight works out to be 25 tons.  There are claims that the energy density could be raised to 40whr/kg, in which case the cap banks would weigh a bit under 3 tons - which is what Bill Farquhar of NCTD (now running commuter rail in Dallas) said was the weight of the dynamic braking system on the FP40's - which wouldn't be needed with a hybrid loco. We might see this in ten years. A 3 ton Li battery pack would work, but lifetime would be a few thousand cycles at most (too short).

An aside about the ultracaps - Oshkosh Truck is working on a hybrid off-road combat transport using a bank of ultracaps behind the cab. Testing is supposed to start in 2008.

My understanding is that GE's hybrid locomotive uses a sodium sulfur battery. It sounds like the battery is being optimized for energy density rather than power density. I also have no idea of what the trade-offs are for depth of discharge, peak power and number of cycles with this battery. I would guess that this battery would work in a turbine locomotive, but don't know if the technology can be pushed to get a useful life from a battery pack light enough for a diesel locomotive. The upsides are that the battery is being developed specifically for locomotive use and that both sodium and sulfur are abundant.

What's the difference between energy density and power density?

Could you explain the battery issues with more depth, and the differences between battery types?

RWM

[Railway Man]

Frank,

 Republic locomotive was proposing to do something close to what you suggested.

A couple of points. The first is that diesel engines throttle down well, you won't gain much in efficiency by shutting down one engine (an exception is where the second engine is HEP only during a layover). The second is that a hybrid would recover a lot of the energy normally wasted in braking.

The gist of what I was proposing was making a hybrid with a high short term power rating - something that would have some of the advantages of an electric passenger locomotive without having to string up wires. 

In prior instances we've experienced main bearing failure on medium-speed stand-alone diesel HEP sets in locomotives when they were shut down and hauled around in trains.  No one was keen about idling them for hours on end either due to fuel dilution issues.  We resolved the problem by taking out the HEP sets.

RWM

[erikem]

What's the difference between energy density and power density?

Could you explain the battery issues with more depth, and the differences between battery types?

Energy density (specific energy might be a better term) is in units of watt-hours/kg, power density (specific power might be a better term) is in units of watts/kg. Using automobiles as an example, energy density is the critical issue for pure electric cars (maximizing range) while power density is more important for hybrid vehicles (want to keep battery weight to a minimum).  There's usually a bit of a tradeoff in maximizing one over the other.

Power density for batteries can range from a few watts/kg for carbon zinc to several kw/kg for Li-ion. Energy densities can range from ~20 w-hr/kg for old lead-acid to 450  w-hr/kg for Lithium-Sulfur (battery operated commuter locomotives are technically possible with Li-S - but expect major sticker shock). Power densities for ultra-caps are around 4 kw/kg while energy densities are 4-5 w-hr/kg assuming full discharge. The advantage of the ultra-caps is being able to tolerate hundreds of thousands of charge-discharge cycles without losing capacity.

I am by no means an expert on battery technology - just know enough to be dangerous. Some generalizations are that most batteries will only support a few hundred full charge/discharge cycles (though some might support a couple of thousand), but lifetime generally increases when depth of discharge is limited.

There is a manufacturer of Li batteries that appears to have something that would work in a hybrid commuter locomotive, but the information is at work, and I'm off until the 2nd. This battery was being marketed as competition to ultracaps, the manufacturer was touting power densities greater than ultracaps and lifetimes of over 100,000 cycles (albeit very limited depth of discharge).

 

[oltmannd]

NJT's GP40Ps, when NJT slide a HEP skid in the place of the steam gen. topped out at over 300,000 (lbs)

I don't know where you heard this, but that's not true whatsoever.  They wouldn't let anything with 75,000 pounds per axle out onto the railroad.  The ex-CNJ Geeps, like other passenger Geeps on other roads, max out at 268,000 pounds.

Not knowingly...  E'port didn't exactly do any real engineering when the slid the HEP in place of the steam genny and opened up the whole fuel tank for fuel.  But they were that heavy when Juniata got them in for rebuilding.  I know, because I did the weight balance on the rebuilt units and we got scale weights on the first one as received.

I could hardly believe it, myself.

[JT22CW]

Ugh.  NJDOT strikes again.  Say no more.

Sad how NJDOT goes from bad to worse by opening up MMC, too.  I've heard too many stories of them putting equipment back out on the road unrepaired.

[YoHo1975]

Amtrak's fleet isn't THAT old, but remember, no matter what they choose, to do they will be begging for money from the federal government

Wow, what a singular problem that other passenger rail does not experience.  Certainly, VIA Rail doesn't "beg for money" from Ottawa, nor commuter rail from their respective state governments, nor DB from Berlin, nor SNCF from Paris, nor JR from Tokyo (in spite of the "privatized" operation companies, the infrastructure is still subsidized).  How is it that Amtrak differs so markedly from these other passenger operators that they must have their own spotlight in spite of their needing to be funded just the same as they do?

I'm not sure I understand your point here. 

I'm sorry; I thought that I was being clear.  I'll spell it out once again, in not-so-sarcastic language:

• All of the railroads that are not Amtrak, that I had listed, all "beg for money" from their respective government(s).
• In the face of that, singling out Amtrak for special castigation over that same point is an unfair attack.

No, I got that, the problem is that I wasn't criticizing Amtrak, so I didn't understand whyyou were pointing this out in the first place.

 

It was suggested that to rebuild Amtrak's fleet could require begging for money from the federal government. My point was that Amtrak exists at the behest of the Federal Government. Everything they do is based on requesting Tax Payer dollars. I was simply Clarifying in response to a previous post.

 

No big deal