Nothing says that it can't. Trains are nuclear powered in France and Japan.
Datafever wrote:Is third rail electrification a viable solution if grade crossings are present?
You can theoretically use third rail if a fail-safe way can be invented to only activate the third rail during locomotive pass over, e.g. the power line is buried underneath the third rail, and the current is transfered to the third rail by relay triggered by the locomotive passing over it. Basically you're using the same technology as is used to activate crossing signals. Problem is, we all have seen crossing signals go off on their own sans an actual train triggering it, and obviously you can't have a third rail becoming electrified due to the same causes.
The LIRR uses third rail and has grade x-ings. 3rd rail can be aukward for crews when switching though. But it is done so it may be viable under certain circumstances.
Even though I do understand most arguements for why deisel is used thru out the freight railroads ((wich in itself might mean I'm brainwashed, hehehe)). Most of the rest of the world electrify as much main line as they can afford, wich just makes me wonder.
greyhounds wrote:In Europe, the trains may be electrically powered, but that freight is going down the highway behind a diesel tractor
How about this?
Now what does this look like…
Closer to home for this one.
Back when the PRR and LIRR were first electrifying, it was one of two competing technologies for electrification—Edison was the champion of DC, against Tesla and AC. The LIRR was also originally looking to use the NYC subway to access NYC, so that would have required using third-rail anyhow (their MP41 EMUs were built to IRT dimensions). Present-day LIRR (as well as some stretches on Metro-North) have the third-rail breaks at grade crossings, which is not terribly effective, but when you run 12-car EMUs, you can have enough access to juice to keep your train going. Third rail becomes a problem when you want to run electric motors (single-unit locomotives); although the NY Central first used motors before EMUs, at locations like Grand Central Terminal they used overhead third-rail to get through gaps at the track-level third-rail.
Also, third-rail has other problems like ground loss of current, not to mention requiring several more substations than AC overhead wire (compare 600 volt DC third rail needing a substation every two miles with 25kV 60Hz AC catenary system requiring a substation every 20 miles).
Please refer to previous posting for answers to a few of the questions raised. To continue, third rail is not practical today for long distances because the highest voltage possible without flashover situations at switches, which require gaps just like grade crossings, is 1500volts. Nearly all third rail lines today are 600 or 750 volts dc. 60 cycles per second AC is used because it is the commercial frequency. Nearly all dual service electric diesel electric locos today are dc 600 or 750 volts on electric, but high voltage AC is required for long distance heavy duty operation with reasonable cost of installation and reasonable spacing of substations. So overhead catenary is essential. The idea of 400Hz instead of 60Hz could be a solution applied on the locomotives, with solid-state electronic conversion at high voltage before step down via the transformers, and this could be a practical breakthough in reducing the cost of powerful dual-service locomotives. I wonder if GE or ED have thought of the idea? This is not off-the-shelf electronics but the technology is available.
The battaries on the CA&E and North Shore passenger cars were for lighting and control circuits and not for power. They coasted across grade crossings. Just like the LIRR and the CTA. And as the NYC did (with grade crossings now gone). And still do through switch gaps. However, the CA&E and North Shore freight locos, several of them, did have battery power capability, and the NYC had triple power, oil engine, battery, and third rail freight locomotives.
daveklepper wrote: Please refer to previous posting for answers to a few of the questions raised. To continue, third rail is not practical today for long distances because the highest voltage possible without flashover situations at switches, which require gaps just like grade crossings, is 1500volts. Nearly all third rail lines today are 600 or 750 volts dc. 60 cycles per second AC is used because it is the commercial frequency. Nearly all dual service electric diesel electric locos today are dc 600 or 750 volts on electric, but high voltage AC is required for long distance heavy duty operation with reasonable cost of installation and reasonable spacing of substations. So overhead catenary is essential. The idea of 400Hz instead of 60Hz could be a solution applied on the locomotives, with solid-state electronic conversion at high voltage before step down via the transformers, and this could be a practical breakthough in reducing the cost of powerful dual-service locomotives. I wonder if GE or ED have thought of the idea? This is not off-the-shelf electronics but the technology is available.The battaries on the CA&E and North Shore passenger cars were for lighting and control circuits and not for power. They coasted across grade crossings. Just like the LIRR and the CTA. And as the NYC did (with grade crossings now gone). And still do through switch gaps. However, the CA&E and North Shore freight locos, several of them, did have battery power capability, and the NYC had triple power, oil engine, battery, and third rail freight locomotives.
The clarification on the limits of third rail use of DC was helpful..thanks. This is more of a theoretical question rather than a practical one, followed by a second. The first is that the use of third rail appears on the surface to be limited to DC strictly for safety reasons that are obvious...in other words, if a.c power was applied, one wonders what the upper limits of it's carrying capacity would be? I would think similar to catenary..maybe? The second question came from the use of 10,000 HP motive power...how long would a average train be if this horsepower was available in a single unit? A related musing...what is the upper limit in length of a freight train? There must be a practical limit...
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has.
The limits are only imposed by coupler strength (on tractive effort, actually, and not really horsepower) and possibly track structure on curves. Electrification is desireable economically only where there is heavy traffic, and so a 10,000 HP locomotive is a possibility and possibly a desirability. Remember that the "best electric locomotives ever built," the New Haven EF-3's, had 9600 HP short-time capability, which they frequently did use hauling hundred car freight at about 40 mph up the grades on both sides to the Hell Gate Bridge. Took three or four GP-9's to do the same job. The trustees bought the ex-Virginians and two EF-4's (PRR E-33's) in multiple could also do the job. The GG-1's had slightly less horsepower, and those regeared from 100 mph to 90 were no slouches in freight service. Again, it was taking freight off the corridor that really doomed the Pennsy electrification for frieght.
When a 10,000 HP real dual service freight locomotive is practical and doesn't cost an arm and leg, say just 20% more than an equal pure diesel, and we are talking about 60Hz AC 25,000volts, then the UP will be interested again. Especially if the neat package is available to add to existing modern diesels. Possibly this 400Hz idea is the way to go!
Another requirement is no increase in real-estate taxes for the electrified rights of way.
And use by the power company for power line transmission.
People tend to forget that the most of the Pennsy Electrification only happed because of government loans given during the Great Depression to help stimulate the economy. PRR had previous electrification in New York because of the tunnels and around Philly for the commuter service. The Pennsy had plans to electrify, but the majority didn't happen until Uncle Sam thought it was a good idea. Most of the European electrification occured because the railroads enjoyed the deep pockets of the governments.
In the early 60s when the P5 fleet was nearing its end, the Pennsy hired THREE consultant companies (they wanted to be sure) to report if continued electric operation was more economic than conversion to diesels. The results were that electric operation was more economic IF you already had the wire. If you needed to borrow money to electrify then diesel was more economic.
At the same time that the Pennsy was evaluating if they wanted to keep the electrification at all they were looking for replacements for the P5s. PRR had Baldwin-Westinghouse build the E3B and E3C ignitron test beds and had GE build the E2Bs which were simply updated AC traction motor locos. When the order was finally let, Pennsy had GE build the E44s using Westinghouse's ignitron technology. Talk about hedging the hedges to the hedges to your bets. But of course PRR was a very conservative corporation.
440cuin wrote: Turbines in stationary power plants run at constant rpms so they are far more efficient at generating electricity then the variable deisel engines in locomotives.
Turbines in stationary power plants run at constant rpms so they are far more efficient at generating electricity then the variable deisel engines in locomotives.
That's just not true. A turbocharged diesel engine has a very nearly linear power vs. fuel curve. Each increment or decrement in fuel gives an equal change in power from notch one thru notch 8.
An SD60 makes 13.71 KW per gallon, duty cycle weighted vs 14.56 in notch 8. Most of the difference is idle fuel offset.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
I thought the Europeans electrified because they didn't have deep enough pockets to build a freeway network as fast as the US was able to afford like the Interstate highways and such. Electrifying was done because it was cheaper and a quicker way to get transport to the large populations in less space available and using less fuel oil wich they had a hard time affording. Now of course Europe has matured it's freeway system but the US was way ahead in the 50' s and 60's.
If deisels are as strong as electrics how come P42DC's don't seem to accelerate even as fast as an AEM7 ?? It doesn't look or feel like they do anyways. I've seen the AEM7 pull a long train out of 30th Street Station and get up to speed impressively quick.
I agree with dldance: the cost of stringing caternary accross the continent would be enormous! As for cost efficacy, don't forget that when European RRs were electrified, most of them were government entities with their own impressive budgets and lots of subsidies, so the costs of electrification were irrelevant.
Since privatization, German Railway refurbished the substations and caternary of a former East-German branch line, but the lines are dead now, because a private competitor was able to provide less expensive service with diesel-electrics. I'm sure that hydrogen fuel cells will play a role in powering the locomotive of the future!
Diesels could certainly be converted to more environmentally friendly fuels over time (bio-diesel, ethanol, recycled fryer grease, etc.).
JonathanS wrote: In the early 60s when the P5 fleet was nearing its end, the Pennsy hired THREE consultant companies (they wanted to be sure) to report if continued electric operation was more economic than conversion to diesels. The results were that electric operation was more economic IF you already had the wire. If you needed to borrow money to electrify then diesel was more economic.
New Haven came to the same conclusion when they re-electrified their freight service between New Haven and Bay Ridge, for which service they purchased the ex-VGN EL-C's since any electrics that were in storage at Cedar Hill were too deteriorated to restore to service.
Lee Koch wrote:I agree with dldance: the cost of stringing caternary accross the continent would be enormous
As for cost efficacy, don't forget that when European RRs were electrified, most of them were government entities with their own impressive budgets and lots of subsidies, so the costs of electrification were irrelevant
Since privatization, German Railway refurbished the substations and caternary of a former East-German branch line, but the lines are dead now, because a private competitor was able to provide less expensive service with diesel-electrics
440cuin wrote:I thought the Europeans electrified because they didn't have deep enough pockets to build a freeway network as fast as the US was able to afford like the Interstate highways and such
JT22CW wrote: Lee Koch wrote:Since privatization, German Railway refurbished the substations and caternary of a former East-German branch line, but the lines are dead now, because a private competitor was able to provide less expensive service with diesel-electricsNot likely that the service is less expensive. Electric service is still cheaper than diesel service. (Which railway are you citing, incidentally?—with all due respect, I must ask for the name, otherwise I'm going to assume this to be hearsay.)
Lee Koch wrote:Since privatization, German Railway refurbished the substations and caternary of a former East-German branch line, but the lines are dead now, because a private competitor was able to provide less expensive service with diesel-electrics
He is obviously talking about the Rubelandbahn. To elaborate on the Rubelandbahn for other readers of this thread, the line is located in the former East Germany on the north side of the Harz Mountains. The main reason for the line is to access high quality Limestone. There are several quarries located near the crest of the mountains at the station of Rubeland. Prior to the electrification in 1965-66 the line was steam powered using powerful 2-8-2T rack locomotives, the final few kilometers into Rubeland is on a 6.0 % grade used the Abt Rack system. At the time of electrification the line was relocated reducing the maximum gradient. The electrification chosen was 25kV/50Hz. to give East German industry experience with the system. The line is connected to the main system but the electrification only runs to the base of the mountains at Blankenrode, so diesel traction is still needed to get the trains to the mainline. A few years ago when the time came to refurbish the electrical equipment, a lot of which was prototype equipment, the DB proposed to replace the electrification with diesels similar to the type 232 of Russian design with an Alco like emissions(i.e plenty of smoke when not fresh from overhaul). Political pressure from the local inhabitants meant money was found to renew the electrical equipment. With Open Access becoming the rule, DB was unable to retain the contracts to haul the Limestone and the new operators brought in diesels after promising to use only models meeting the latest emissions standards. The main model used is the Bombardier/GE Blue Tiger (a AC3200C double cab). Within the last year there is a renewed push to get the trains electric powered and to extend the electrification through the small city of Halberstadt and to the mainline near the Landhauptstadt (State Capitol) of Magdeburg.
John Beaulieu
Yes I know the Europeans had the early Autobahns and stuff, but the USA built much bigger and longer freeways from the 50's on. Also the Autobahns were very straight but not realy very wide at fisrt compared to the big US highways and bridges. I also realise that Europe has a very extensive freeway system now.
MichaelSol wrote:1. Cost of fuel.
1. Cost of fuel.
And carbon offsets if we ever conclude that CO2 is as bad as the enviro's think it is.
2. Equivalent cost of electric power. Currently, the cost of equivalent electric power is about 54% of the cost of diesel at $2.20 per gallon. For the DC systems I am familiar with, about 72% of the substation metered power gets to the rail. This results in an equivalent electric power cost at the rail of about 76% of the cost of diesel fuel.3. Cost differential due to regeneration. For a typical Western railroad profile, 15% of cost at the substation meter can be recovered by regeneration, offering a final equivalent electric power cost at the rail in favor of electrification of just about 65%.
2. Equivalent cost of electric power. Currently, the cost of equivalent electric power is about 54% of the cost of diesel at $2.20 per gallon. For the DC systems I am familiar with, about 72% of the substation metered power gets to the rail. This results in an equivalent electric power cost at the rail of about 76% of the cost of diesel fuel.
3. Cost differential due to regeneration. For a typical Western railroad profile, 15% of cost at the substation meter can be recovered by regeneration, offering a final equivalent electric power cost at the rail in favor of electrification of just about 65%.
I'm wondering if a high voltage (10 KV or so) DC system might be the way to go, using a "large scale" DC/DC converter on the locomotive to convert from the contact wire voltage to the internal bus voltage (the internal bus would be similar to the current AC motored Diesels) and you could even hang an energy storage subsystem (batteries, ultracaps or flywheels) to allow for power or regenration through gaps in the overhead.
Adavantages of a DC system include:
1. No phase unbalance from the power grid and better isolation from the grid.
2. Would be a lot easier to make use of regeneration.
Disadvantages include:
1. Electrolytic corrosion.
2. Substations more expensive than commecial frequency substations.
spikejones52002 wrote:it would be a lot cheeper and effecient if they went to 400hz instead of 60 hz. All the controls would be smaller and more effecient. Once they standarized 400 hz the cost would drop considerably.
it would be a lot cheeper and effecient if they went to 400hz instead of 60 hz. All the controls would be smaller and more effecient.
Once they standarized 400 hz the cost would drop considerably.
Not really.
The problem with 400 Hz is that it isn't suited for long distance transmission - inductive voltage drop is almost 7 times worse than at 60 Hz and skin effect starts raising resistive losses. I suspect it would be quite a challenge to design an MVA class transformer to operate as efficiently at 400 Hz as currently available transformers do at 60 Hz.
But conversion from 60Hz to 400Hz with power solid state electronics on the locomotive may be possible as developments in semiconductors progress. And that should drastically reduce the size, weight, and cost of transformers, which are one huge ticket item in ac 60 Hz 25000volt electrics.
Michael, we have to stick with 60Hz AC because it is what the power companies provide and transmit. To go to high voltage dc would make sense, but you would then need power conversion at the substations in addition to doing again on the locomitve. The added costs would greatly outway the economies.
I had not thought of frequency conversion right before the transformers to 400Hz until reading this thread. I wonder if GE or EMD have thought of it?
If dual-mode heavy-duty electrics-diesel electrics were available, electrification could come gradually without the need for frequent engine changes. This would remove one of the obsticacles. Again, perhaps in some cases the power companies could make the investment. It is their coal that is burned to make the electricity, and they pay for the transport of the coal.
Regarding the New Haven at the time of the purchase of the ex-Virginian N&W electrics: They did have to put new wire up from the east end of the New Haven Railroad Station to Ceder Hill Yaard and some of the yard tracks. plus most of the wire on the LIRR Bay Ridge Branch, and at Oak Point Yard in the Bronx, a good 15% of their electrification. Then Conrail took this wire down again! And Amtrak has put some of it back up as part of the electrification to Boston. The posts were still in place.
Michael S., I hate to send you digging through your papers again...but I believe you have mentioned in the past a 1970's proposal by some PNW electric utilities to finance renovations of the MILW's PCE electrification. What was the payback mechanism? Just an added price to the electricity sold? Did the proposal cover the entire electrification system (transmission lines, catenary, poles, substations)? What about locomotives? Would it have filled in the "gap"? What was the payback time for their investment?
Anyone know if utility financing has been looked at for electrification schemes since then?
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
No contemporary heavy (western) electrification? I forgot this one..link to photos
http://www.drgw.ws/gallery/gallery.asp?on=20060926
beaulieu wrote: JT22CW wrote: Lee Koch wrote:Since privatization, German Railway refurbished the substations and caternary of a former East-German branch line, but the lines are dead now, because a private competitor was able to provide less expensive service with diesel-electricsNot likely that the service is less expensive. Electric service is still cheaper than diesel service. (Which railway are you citing, incidentally?—with all due respect, I must ask for the name, otherwise I'm going to assume this to be hearsay.)He is obviously talking about the Rubelandbahn. John Beaulieu
He is obviously talking about the Rubelandbahn. John Beaulieu
Exactly! And I might add, as I've mentioned on another thread, that open access has led to a plethora of private rail freight haulers turing to the newest generation of diesel-electrics, although most of Germany's main lines are electrified, albeit at 15kV/25Hz. I don't really know to what extent their use of diesels is dependent on overpriced power rates charged by the Deutsche Bahn/German Railway, which, despite open access, still manages the ROW.
As to JT's mention of the Trans-Siberian, well, the railroad and the power company are both State monopolies, so you can't really compare that with North America. Sure, electrification would be possible, but it's not just the initial capital investment in putting up the caternary; you also have to maintain it, even in remote areas!
The Electrification was just about studied to death between 1968 and 1972. Several proposals were made.
1) The L.W. Wylie study of 1968. Proposed upgrades, electrifying the Gap, proposed a new electric locomotive design to be ordered up. A detailed engineering study that showed compelling cost operating advantages, but left it to the railroad to determine the best means of financing the upgrade. This study generated a great deal of internal review and, in turn, stimulated suppliers to propose equipment and actual costs to supplement the study.
2) The three largest PNW electric utilities -- Puget Power & Light, Washington Water Power, and Montana Power Company -- put together a joint study and made a joint proposal. 1970 if I recall correctly.
They favored continued DC operation based on their own study which showed that the DC was superior to AC for the Milwaukee's mountain operations, closing the gap, and purchasing new locomotives from GE, upgrading the system overall with silicon diode rectifiers, and raising the voltage to 3,900 vDC.
Financing was a combination of salvage sales (replacing copper with aluminum on feeder), loans, and wheelage fees on the Milwaukee high voltage line; possibly from sales revenue generated from sales of the lines to the power companies.
3) An updated Power Company study was submitted to the Milwaukee in 1971, based on GE and EMD actual price quotes for motive power.
4) GE made a detailed proposal in 1972 to upgrade the entire system. It was instigated by the power company study. GE agreed with most elements of the power company study, including recognition that the existing DC system would be superior in operation to any alternative AC system. GE's proposal was more detailed than any prior study and, at least from a presentation standpoint, made a clear and detailed presentation based on GE's "Econometric Computer Program" and took the analysis clear through to a "before tax" and an "after tax" scenario.
5) The MILW legal department's proposal to re-electrify using a high voltage, state-of-the-art AC system, financed almost entirely by a $250 million grant from the FRA as a demonstrator project for railroad electrification. FRA had approved it; all that remained was MILW board approval.
6) MILW internal studies, ongoing. An interesting one was done by VP Management Services Gaye Kellow when he pointed out in 1970 that the most economically efficient system was a combined electric/diesel system like the Milwaukee was currently operating, rather than going either all-electric or all-diesel.
The GE analysis showed that upon full operation in 1974, the system would have generated a net pretax savings at a 2.7% growth rate in traffic of $30,000. By 1980, the savings would have been just under $1 million annually at 2.7% or $1.4 million annually at a 5% growth rate, assuming diesel fuel at 16 cents per gallon by 1980. Total accumulated savings in each case by 1980 was $3.2 million and $4.8 million. By 1985, the savings would have been $8.9 million and $16 million respectively.
In the all cases, the underlying assumptions of rate of growth and rate of diesel fuel cost increases were far too conservative, and actual savings would have been much greater.
Over the estimated life of the system, by 2003 the respective total savings would have $221.6 million and $403 million. In that year, the annual savings would have reached $24 million and $49 milllion respectively.
As it turned out, with substantially greater growth in traffic in the electrified zones, and substantially greater increases in diesel fuel costs than projected in the study, Milwaukee would have saved closer to $20 million by 1980 in annual operating savings.
MichaelSol wrote: The Electrification was just about studied to death between 1968 and 1972. Several proposals were made.1) The L.W. Wylie study of 1968. Proposed upgrades, electrifying the Gap, proposed a new electric locomotive design to be ordered up. A detailed engineering study that showed compelling cost operating advantages, but left it to the railroad to determine the best means of financing the upgrade. This study generated a great deal of internal review and, in turn, stimulated suppliers to propose equipment and actual costs to supplement the study.2) The three largest PNW electric utilities -- Puget Power & Light, Washington Water Power, and Montana Power Company -- put together a joint study and made a joint proposal. 1970 if I recall correctly. They favored continued DC operation based on their own study which showed that the DC was superior to AC for the Milwaukee's mountain operations, closing the gap, and purchasing new locomotives from GE, upgrading the system overall with silicon diode rectifiers, and raising the voltage to 3,900 vDC.Financing was a combination of salvage sales (replacing copper with aluminum on feeder), loans, and wheelage fees on the Milwaukee high voltage line; possibly from sales revenue generated from sales of the lines to the power companies.3) An updated Power Company study was submitted to the Milwaukee in 1971, based on GE and EMD actual price quotes for motive power.4) GE made a detailed proposal in 1972 to upgrade the entire system. It was instigated by the power company study. GE agreed with most elements of the power company study, including recognition that the existing DC system would be superior in operation to any alternative AC system. GE's proposal was more detailed than any prior study and, at least from a presentation standpoint, made a clear and detailed presentation based on GE's "Econometric Computer Program" and took the analysis clear through to a "before tax" and an "after tax" scenario.5) The MILW legal department's proposal to re-electrify using a high voltage, state-of-the-art AC system, financed almost entirely by a $250 million grant from the FRA as a demonstrator project for railroad electrification. FRA had approved it; all that remained was MILW board approval.6) MILW internal studies, ongoing. An interesting one was done by VP Management Services Gaye Kellow when he pointed out in 1970 that the most economically efficient system was a combined electric/diesel system like the Milwaukee was currently operating, rather than going either all-electric or all-diesel. The GE analysis showed that upon full operation in 1974, the system would have generated a net pretax savings at a 2.7% growth rate in traffic of $30,000. By 1980, the savings would have been just under $1 million annually at 2.7% or $1.4 million annually at a 5% growth rate, assuming diesel fuel at 16 cents per gallon by 1980. Total accumulated savings in each case by 1980 was $3.2 million and $4.8 million. By 1985, the savings would have been $8.9 million and $16 million respectively. In the all cases, the underlying assumptions of rate of growth and rate of diesel fuel cost increases were far too conservative, and actual savings would have been much greater.Over the estimated life of the system, by 2003 the respective total savings would have $221.6 million and $403 million. In that year, the annual savings would have reached $24 million and $49 milllion respectively.As it turned out, with substantially greater growth in traffic in the electrified zones, and substantially greater increases in diesel fuel costs than projected in the study, Milwaukee would have saved closer to $20 million by 1980 in annual operating savings.
Fascinating insight into this topic from an historical viewpoint....
MichaelSol wrote: 5) The MILW legal department's proposal to re-electrify using a high voltage, state-of-the-art AC system, financed almost entirely by a $250 million grant from the FRA as a demonstrator project for railroad electrification. FRA had approved it; all that remained was MILW board approval.Over the estimated life of the system, by 2003 the respective total savings would have $221.6 million and $403 million. In that year, the annual savings would have reached $24 million and $49 milllion respectively.As it turned out, with substantially greater growth in traffic in the electrified zones, and substantially greater increases in diesel fuel costs than projected in the study, Milwaukee would have saved closer to $20 million by 1980 in annual operating savings.
Thanks to Chris / CopCarSS for my avatar.
I owe Michael an apology: An old issue of Technology Review, the MIT Alumni magazine, showed the advantages of high-voltage dc transmission, as high as 100,000 volts, 100kV. The new power line partly under water (under rock and sand under the water) helping to resolve power shortage on Long Island, is dc. Using the latest technology, and converting to 400Hz directly following the pantograph to minimize size, weight, and cost of transformers, would allow the locomotive to operate equally well off dc, 60Hz ac, or the 25Hz ac that remains on the southern portion of the NEC (Sunnyside, Queens, NY - Washington). The electrification would be more logical if the railroad right-of-way was also used by a new modern power transmission line, and it would be the power company's decision whether 60Hz ac or direct current were used, and the locomotives could accept either.
Why 400Hz? It is a frequency that allows efficient transformer design. (At MIT, I helped fund my expenses by designing transformers for Mystic Transformers in Winchester. My commute was on the B&M, and I had the engine pass given me by Ernie Bloss, in connection with my part-time work on the B&M, following a summer as student engineer at EMD in La Grange, where I had some input to the design of the GP-9 in 1952.) Lower frequencies require more mass in the magnetic structure to avoid saturation, while higher frequencies involve capacitor coupling losses across coil windings and across insulation between core and wire plus additional hysterisus losses in the core. Hsyterisus: The energy-change in the core lags slightly behind the change in core current, not a problem at 400 Hz, but a problem as frequencies climb. Also, if goes much above 1000Hz, radio interference and inteference with signal systems can be a problem unless shielding is well designed and maintained.
daveklepper wrote:I owe Michael an apology: An old issue of Technology Review, the MIT Alumni magazine, showed the advantages of high-voltage dc transmission, as high as 100,000 volts, 100kV. The new power line partly under water (under rock and sand under the water) helping to resolve power shortage on Long Island, is dc. Using the latest technology, and converting to 400Hz directly following the pantograph to minimize size, weight, and cost of transformers, would allow the locomotive to operate equally well off dc, 60Hz ac, or the 25Hz ac that remains on the southern portion of the NEC (Sunnyside, Queens, NY - Washington). The electrification would be more logical if the railroad right-of-way was also used by a new modern power transmission line, and it would be the power company's decision whether 60Hz ac or direct current were used, and the locomotives could accept either.Why 400Hz? It is a frequency that allows efficient transformer design. (At MIT, I helped fund my expenses by designing transformers for Mystic Transformers in Winchester. My commute was on the B&M, and I had the engine pass given me by Ernie Bloss, in connection with my part-time work on the B&M, following a summer as student engineer at EMD in La Grange, where I had some input to the design of the GP-9 in 1952.) Lower frequencies require more mass in the magnetic structure to avoid saturation, while higher frequencies involve capacitor coupling losses across coil windings and across insulation between core and wire plus additional hysterisus losses in the core. Hsyterisus: The energy-change in the core lags slightly behind the change in core current, not a problem at 400 Hz, but a problem as frequencies climb. Also, if goes much above 1000Hz, radio interference and inteference with signal systems can be a problem unless shielding is well designed and maintained.
One question I have about your point of less weight, what is the advantage if you are going to have to add concrete and steel to the locomotive to bring the weight up for adhesion purposes. I realize the cores of the transformers are special iron alloys, but weight savings when you have eliminated the diesel and the fuel, is not of prime importance, for passenger service yes, for freight no. One other question not much discussed, Michael mentions 3900V DC, if you are going to have reasonably powerful locomotive consists you are going to have to have large current flows, and hence a pretty good cross-section on the contact wire. If you assume a locomotive consist of say 14 MW yielding a current draw of 3580A. 6000A is a common load limit for a substation, this would not be enough for two trains to be drawing full power in any section.
IIRC the electrical systems in Boeing jets uses a frequency higher than 60hz but I can't remember what it is. The stated reason was to save weight. If it is 400hz then there is a catalog of transportation/reliability certified electrical components to draw from.
dd
ps re: weight savings -- concrete is a lot cheaper than copper.
dldance wrote:<snipped> ddps re: weight savings -- concrete is a lot cheaper than copper.
<snipped>
But is anything saved in removing a smaller amount of copper from the locomotive only to hang more of it from cantenary supports? Also, the savings in transformer weight are from the iron core, not the copper windings.
Jetliners use 400Hz electrical power.
beaulieu wrote: One other question not much discussed, Michael mentions 3900V DC, if you are going to have reasonably powerful locomotive consists you are going to have to have large current flows, and hence a pretty good cross-section on the contact wire. If you assume a locomotive consist of say 14 MW yielding a current draw of 3580A. 6000A is a common load limit for a substation, this would not be enough for two trains to be drawing full power in any section.
One other question not much discussed, Michael mentions 3900V DC, if you are going to have reasonably powerful locomotive consists you are going to have to have large current flows, and hence a pretty good cross-section on the contact wire. If you assume a locomotive consist of say 14 MW yielding a current draw of 3580A. 6000A is a common load limit for a substation, this would not be enough for two trains to be drawing full power in any section.
In contrast to AC practice, a DC "section" consists of two substations.
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