Again, Blue Streak, sent to EMD and GE a few years ago:
I ran across an interesting article in the Electronic Design newsletter about Cree and Delphi partnering to make 800V inverters for a "major OEM". This comes on the heels of Porsche working on 800V batteries for a high performance electric car with very fast recharging - and corresponding power levels.
The inverters would be a bit light for a locomotive, but would be just fine for an inverter per axle installation on an electric M.U. car. Availability of quick charge batteries would mean that a battery M.U. could be put together with off the shelf components.
FWIW, the 800V rating is likely from the wide availability of 1200V SiCFET's, with the 50% higher breakdown voltage to limit damage from cosmic ray induced neutrons.
Thoughs on my proposal to place a electric between 2 regular locos. Shorter power cabling. When in diesel mode the extra traction motors on the "E" unit allow for a lower speed for using full HP of the diesels. That allows for faster acceleration from stops and less wheel slip that can cause derating traction power.
9 axels spread over the standard 4400 HP means 477 HP per axel instead of of 733 HP per axel for pure diesel operation. Of course need for not exceeding drawbar limits would need consideration. Using this configuration up and down Horseshoe probably would allow freigt trains to meet the MAS of passenger trains.
My recollection is on the order of two feet. Another recollection was that initial wire height was set to allow for the tops of the rails to be raised from subsequent ballast work to maintain that two foot clearance.
Erik_MagTarget for clearances was 50kV over double stacks.
Do you remember (or can you find) the allowance for corona at 50kV in different "Southern California" weather and climate conditions? I'm driving to Erie and can't look for it or search the Web.
IIRC, the Alameda corridor was designed to accomodate electrification. This was mentioned in the 1991-92 study on electrifying the freight railroads in southern California. Target for clearances was 50kV over double stacks.
Alameda would also be a good canadate for overhead cat as well..
Dave,
A slight correction, BART has been using 1000VDC third rail for 47 years and Central California Traction used 1200VDC third rail for a bit over three decades. OTOH, the Michigan 2400VDC third rail installation was a failure.
800-volt third rail is entirely practical for tunnel or trench electrifications. 1000 volts was used by one interurban without severe problems.
Starting to see datacenter requirements for equipment to use +/- 240-380 VDC feeds as DC-DC converters have improved efficiency. Those designs also eliminate the inverter in the UPS systems.
I always thought the Alameda Trench in Southern California would be a great use for this setup.
The presentation I saw on GE locomotives (late 2005) showed 800VDC for the inverter DC link. This would jibe with the wide availability of 1500V to 1700V IGBT's as silicon HV power devices are typically operated at half of the rated breakdown voltage. Reason for this is to limit damage from cosmic ray neutrons.
The advantage of IGBT inverter per axle over GTO thyristor inverter per truck is that the DC bus voltage can be held constant as IGBT inverters can operate in PWM mode over the whole speed range where at high speeds the GTO's had to operate at the motor drive frequency and needed to control drive voltage by varying the DC link voltage.
From what I understand, most diesel-electrics and most straight-electrics use a "1000-Volt DC power rail." Meaning that the AC from the pantograph or from an alternator-genjerator is recrified to 1000V DC before the computer-controlled inverters produce the variable current and frequency that today's AC rotating slant-bar morors require. So hefly hi-amp conductors, two for current and one for ground, would be requiredf. There would be stringent safety rules in the handling of the flexible connecting cables (reverser in the off position in all locomotives being connected or disconnected one basic rule), and normally road crews would not be involved.
rdamonI was thinking more of a lower common 'bus' voltage like 600V, like what is done for slug sets. As mentioned before this looks to be more of a captive set where field separation would be the exception.
I think there is relatively little difference between using a nominal DC-link voltage (which I think is around twice that you mention, spiking to about three times) in this application, since good insulating systems (and associated fabrication and maintenance knowledge) is available from HVDC power-tie experience. If you assume (as I think is wise) that the power connections will not need to be broken and made except under controlled conditions (unlike, for example, an uprated version of HEP connectors, which would technically possible) there should be relatively little difficulty -- the chief one, in my opinion, being how the power connection gracefully and safely separates should the traction coupling between units fail or stretch, or something snag and pull the cabling.
I am not sure that limitation on voltage that was originally made with respect to commutator integrity and winding-insulation limits is a desirable precondition -- isn't 600V still at the high end of the lethal range for shock vs. burn damage? The question then does arise that any sort of ground fault or leakage at higher peak voltage might lead to dangerous voltage and current in unexpected places, some of which (like parts of the air system) might involve ungloved contact while effectively shorted to ground...
These issues are less important if the units are 'dual-mode-lite' because there need be no umbilical connections between units. (Isn't it a pity that Reading-style roof connections for HVAC are no longer possible! )
Probably the best means of providing 'telemetry' other than through something like the DPU communications would be to impose modulation on some of the wires in the 'standard' MU connection -- perhaps using one of the schemes used for powerline modulation. That would retain 'stock' compatibility of the MU cables and other components, while allowing better self-discovery, configuration, etc. between connected aware units.
I was thinking more of a lower common 'bus' voltage like 600V, like what is done for slug sets. As mentioned before this looks to be more of a captive set where field seperation would be the exception. Agree that safety would be a big concern.
I could also see where the MU would need to be more of a datalink between all the systems for telemetry and control since this would operate like a single unit.
More things to break ;)
rdamonThe inverter per axle does open up the possibility of a power bus that is fed from the PAN, 3rd Rail, the unit's power or [from] a genset [on] other units.
Does not require one inverter per axle; supplying the DC link voltage 'directly' provides what would otherwise be the rectified DC any of the inverter designs uses to modulate the AC synthesized output.
The problem with multiple inputs is, I think, considerably less with this particular approach than the documented history (fraught with fiery disaster -- remember "fifteen minutes earlier and I would have been a hero"? -- with straight DC. Switching third rail at high amperage was often the part where the gremlins started to play.
I believe there were comparatively recent discussions about converting some of the current dual-mode (diesel and third rail) units to tri-mode, and a major stated reason for not proceeding with that alternative was the switching difficulties involved with the multiple power sources. Europeans of course seem to have little problem with up to four voltages (some of them HVDC) easily switchable during a given run, and I have never really understood why delivering one of those voltages through a third rail should cause insufferable difficulties -- especially with modern solid-state high-current switching making third-rail shoe and bus design much less critical.
Connecting the bus should be no more complex than a mid consist fuel tender.
Trust Mr. Klepper and me when we tell you that high-voltage connections between units are NOT the same kind of field-breakable connection that a diesel fuel line -- or even a cryomethane line -- represents. There are all sorts of interlock concerns, weather caps when disconnected even briefly -- look at the whole grim history of couplers with integrated air and electrical connections.
Not insurmountable, of course, but I think both you and I don't want to put employees at risk, especially a few years down the road as the connectors and their various insulating seals begin to degrade.
Would need a more robust MU hook-up.
Probably not. Generations of electrics were built specifically to MU correctly with diesels, and the task is considerably easier today (either with conversion of 27-pin MU signaling 'on the fly' or through use of DPU). I see little if any reason to build the 'conversion' units with anything but a compatible 8-notch throttle and other controls posing as little 'unusual behavior' or special handling needing retraining as possible.
The inverter per axle does open up the possibility of a power bus that is fed from the PAN, 3rd Rail, the units power or as a gen set from other units.
One little fun possibility is that if you do an ECO repower of a 16-cylinder 710 with a 12-cylinder engine, as in the SD60M rebuilding work in California a decade ago (for relatively unsuccessful Tier 4 experimentation), you probably have neat room, and perhaps overhead 'well' space for the pan, to do a dual-mode-lite packaging job in the space that's opened up. Remember that for AC the transversion required is only the provision of properly-smoothed DC (not too terribly high-voltage either) with appropriate spike/sag protection to the input of the inverters; this is much less of a job than having to provide variable DC to a conventional traction-motor setup.
Presented this idea years ago to both GE and EMD. The day may come. Certainly makes electrification more practical.
Only problem is the handling of power cables between units. Does also give new life for four-motored cores, with the three-unit consist giving the tractive effort of two six-motored units.
blue streak 1Imagine a loco consist of a standard AC loco - a 6 axel electric motor - standard AC loco. The consist would operate in non CAT territory with the prime movers suppplying power to its traction motors by way of inverters and one 3-axle inverter set of the electric motor. Then when under CAT pan raised and the unit then provides power to all traction motors.
I confess I was thinking more about a revival of the 'dual-mode lite' program that Conrail was considering in the early '80s, in which the 'electrification' only substituted for the combustion-engine input to the basic electrical installation on a diesel-electric locomotive. (Don Oltmann can probably describe this in wonderful detail; there used to be a couple of engineering papers about it on the Web.) This of course is facilitated by AC locomotives, not so much because the "drive" uses AC as because simple transversion to the DC link voltage probably suffices for the additional 'new' power provision (at least in the early stages of any catenary-provision program)
It's an interesting idea to treat the pure-electric machine as a kind of MATE or road slug when not under wire. One thing this suggests is that control cabs for the 'consist' be provided there, and not run it as a permanent B unit -- this would also allow some of the fancy modern control equipment, camera suites, etc. to be localized for the 'electric zones' where the combined power would operate. Crews get positive benefit from quiet, relatively fumeless operation, I think.
The remaining space in the 'electric' unit might be occupied with some form of adapted wayside storage or 'alternative energy' hybrid power source, especially if Government programs encouraged or rewarded capital investment in 'green' or carbon-reducing technologies for railroad applications. This would allow reduced operation of the combustion motors, either in delivered power or in shutdown over time. GE apparently chose not to pursue implementing the necessary storage capacity on a normal-horsepower 'hybrid' locomotive sometime around 2010, but a larger and cooler installation might turn out to be more workable now.
I would suggest that transition to this kind of system and provision of 'dual-mode lite' are not mutually exclusive: the dual-modes would inherently have the ability to access the catenary, and might serve as primary pantographs for the much more capable pure-electric motor arrangement. I think the French have conducted (no pun intended) all the necessary research on high-voltage transfer through cabling to allow this, including the necessary interunit connections, to reduce it to a technical exercise instead of an experimental test.
The choice of power involved will of course depend on economics ... including a willingness to tap alternative sources of capital to get the initial work done. We should keep in mind always that the power needs to be 'as compatible as possible' with efficient operation outside electrified areas, while increasingly providing an incentive for expansions outside, rather than necessarily contiguous with, any existing electrified zone.
When going down other side of Horseshoe regeneration would send power back into the CAT providing supplental power to the grid for another train climbing either side of the grade.
Having to 'match' electrical generation with instantaneous demand is no longer necessary, as is having to worry about sufficient traction power. I suspect any sensible electrification 'island' built in the future would contain substantial distributed wayside power storage (including relatively short-term kinetic storage) together with means to distribute any peak or transient 'overage' to the general grid or to selective consumers within the grid. So reasonably full regenerative braking will always be available as needed (just as, theoretically, full electric traction power, up to the limits of the delivery infrastructure, can be).
[quote]This type unit will require some engineering to install a possible 20,000 HP capable transformer, power distribution cables between units, control software and cabling. Also somewhat higher HP traction motors on the electric loco motor unit.[quote]
This would be so for a 'combination' that used (relatively) unmodified AC units to run in the electrified zones. The question then is whether the cost to modify the AC units with the appropriate DC-link ties to connect with a necessarily-attached "MATE" is more cost-effective and sensible-to-the-railroad than providing dual-mode lite on them in the first place. This is more of an issue when there is asymmetrical traffic flow over an electrified zone sufficient to put 'too many' of the dedicated AC modules on the wrong side, or have too many of them relatively 'deadheading' in transit for the equivalent of power balancing. You may remember that a similar issue killed the electrification on the Virginian, otherwise quite technically and operationally successful.
The electric motor could be a retired AC unit with all prime mover equipment removed and the electric equipment installed.
An interesting idea. Certainly a quick way to get into the 'business' without a great deal of expense for new construction. I suspect that much of the required electrical gear parallels that for a dual-mode lite, or could be designed to take advantage of compatibility with it, so the actual high-amperage-capacity equipment would need to be relatively little. I'd at least consider whether using very-high-powered TMs in that application is truly necessary, as I have to wonder whether control problems 'matching' six axles of high power with twelve that were designed for constant-horsepower source might be greater than the theoretical advantage would warrant in practice.
Note that with the enormous number of locomotives 'stored serviceable' in part because of the characteristics of their combustion engines you'd have a wide range of choices for conversion.
Probably add and subtract these sets at crew change points.
The original 'best use' of electrification would, I think, be in helper districts, so some change-point determination similar to that used for existing helpers would be possible, and probably quite likely. I do think that having any 'pure electric' module on the head (or tail) end would facilitate any required addition or removal from a consist, compared to cutting the whole power off and having it stand idle when not in actual use; some of the acknowledged issues with brakes, rebooting PTC, etc. might make this less attractive in reality than in theory.
How this changes as you get further and further toward extended run-through under wire is interesting, but difficult to predict. Probably not a good idea to overspecify what is initially built, or the scope of equipment actually converted at a given time.
One problem is that this would require captive loco sets although NS does have its loco facility close by. Regular locos might often be needed to dead head to/ from Altoona?
Helpers probably 'count' as captive loco sets already. Technically any conversion efforts would 'begin' with electrifying whatever power is to be used for the helper pool -- the catch here being that older units are more likely to be chosen for this duty, and these are the least likely to receive sophisticated upgrades, so here again the dual-mode lite seems to have substantial advantage (especially if reduced to a 'kit' for install on particular locomotive types).
For yards these sets eliminate the need for many tracks to install CAT.
Very likely, most yard tracks wouldn't get catenary; almost certainly not constant-tension catenary. It's not really needed for the initial purposes electrification is most valuable; energy storage in otherwise-conventional designs of existing switch and transfer engines can handle the 'marshalling' of trains delvered by electrically-compatible consists. In areas where full electric switching is desirable -- for example, California air-quality management districts -- let their governments pay their fair share for once.
Outside full electrification there could be short sections of CAT to provide help up hills and for acceleration from planned stops.
This is of course one of the salient advantages of dual-mode-lite equipment, and is also a great opportunity for periodically-precharged wayside storage instead of large fixed substation capacity for the required purposes. A concern I have is that whatever sections be provided are capable of effective constant-tension construction, and that they be fully compatible with any future extension work also in constant-tension. That is probably piddling for the consulting engineers doing the work -- provided it is a known design criterion before work starts.
For Amtrak the Pennsylvanian could use its normal P-42 and an ACS that would be able to increase speeds up the grades under the CAT. Or a dual mode unit such as the ALP-45 could be used however Amtrak has a well documented adversity to one off type units.
I would note that the dual-mode-lite conversion might work as effectively for a GE monocoque passenger unit as for other GEs with comparable engines and electrical gear. A power pool for the Pennsylvanian, even with extended service, would probably not involve *that* many units, so the extended question becomes whether external AC 'snapping' is preferable to dual-mode AC operation.
The ALP45 is an overripe tomato of a solution, almost certainly not an answer any operator other than a government-funded transit authority could use (or, perhaps, tolerate). I certainly don't see an Amtrak budget containing the necessary funding to build 'more of that sort of thing' for the initially relatively small gains for run-through service. (An ALP45 would have been a logical locomotive for the ACE service, but instead we saw top-and-tail with one electric and one diesel -- and I think the people at Amtrak who made that decision are still in a position to explain their logic.) There's also something of a 'history' for designs of diesel-electric with variable power supply -- the genset switchers, and those Caterpillar locomotives with a C18 as sustainer engine -- but the history up to this point is rife with failure and not much meaningful success. (There are some things that evidently haven't been tried successfully, a large one of which is predictive start/stop of genset engines, but that's probably not reflective of current state-of-the-art in the market for those things...)
One of the theoretical points of dual-mode-lite as considered for Conrail was -- and Don can correct me if I remember wrong -- that you could continue using the combustion engine in parallel with the overhead to supply the traction motors, so the actual power drawn from the overhead wire need not be the full demanded traction power. This is particularly attractive if considering use of catenary only for 'snapping' as the electric installation need only cover the incremental HP that the TMs can use rather than the entire power consumption when under wire.
I like that idea. Basically you have a 3 unit "Gen Set" dual powered. With a common power bus between them even a small HP set in the 'E' unit can be used if there is room.
Overmod My approach is different: provide electrification where it offers clear incremental advantages, especially to 'cheaper' PSR -- for example, in the helper district over Horse Shoe, or Cajon, or in some of the air-quality management districts in California where incentives might be brought to bear -- and then when a critical mass of capital and experience with dual-mode power and road slugs has been obtained, perform incremental buildout of more capacity with grants, etc. as appropriate.
My approach is different: provide electrification where it offers clear incremental advantages, especially to 'cheaper' PSR -- for example, in the helper district over Horse Shoe, or Cajon, or in some of the air-quality management districts in California where incentives might be brought to bear -- and then when a critical mass of capital and experience with dual-mode power and road slugs has been obtained, perform incremental buildout of more capacity with grants, etc. as appropriate.
caldreamerWe now have so much natural gas that the prices are dirt cheap and will remain so for a very long time.
charlie hebdoHopefully we will get up to date on the high-traffic-density mainlines with contemporary electrification.
I think part of the issue is that any'politically correct' country we might buy constant-tension cat infrastructure and locomotives/components from would charge the "usual" arm and a leg for the privilege; the countries that seem to know how to shoestring it (e.g. apparently Spain) and those who have effectively costed-down the supply (China) don't have the clout to convince any railroad benefiting from full electrification with substantial renewable supply to "take the plunge". To me it's a bit like ECP: if the technology has to be pervasive to be adopted and the buy-in costs appear high, only government intervention or something like it is likely to make railroads realize, or pretend to recognize, their best interests a la dieselization.
Overmod chicagorails What's better now? Gas or electric locos? Neither one has a clue. Ross Rowland tried reasonably well to work out a system with CNG, but in spite of a first-rate team it seems to have gone nowhere commercially. Perhaps that is for the best as the explosion hazards of CNG are, in my opinion, insurmountable in a railroad environment. There is some possibility, relatively small, that a locomotive-size use of some of the large stationary-battery ('wayside storage' in the transportation context) systems may have enough energy density combined with robust behavior in charge and discharge to be suitable for some applications. Perhaps this time around someone who has actually observed effective flat switching will be in charge of the detail design and programming. Personally I doubt even the most promising of these (vanadium, perhaps) is up to the job of pure BEV operation, so we default back to the sort of thing GE tried a decade ago, the issue then being one of cost vs. 'environmental' benefit or perception. Not enough grant money or tax incentive yet! I still think there is something in LNG as a practical co-fuel, but that is because I have a soft spot for different methods of using cryomethane in transportation -- ways that do not lend themselves compellingly to modern PSR-optimized motive power, anyway. Still ... if you want to use gas for anything other than a synthesis feedstock for liquid fuel, or maybe at the outside a reformer feedstock for fuel-cell hydrogen, that's about the only technology with the necessary safety. Probably best to keep it powering the grid and argue for progressive lineside power sourcing and dual-mode-lite locomotives.
chicagorails What's better now? Gas or electric locos?
Neither one has a clue.
Ross Rowland tried reasonably well to work out a system with CNG, but in spite of a first-rate team it seems to have gone nowhere commercially. Perhaps that is for the best as the explosion hazards of CNG are, in my opinion, insurmountable in a railroad environment.
There is some possibility, relatively small, that a locomotive-size use of some of the large stationary-battery ('wayside storage' in the transportation context) systems may have enough energy density combined with robust behavior in charge and discharge to be suitable for some applications. Perhaps this time around someone who has actually observed effective flat switching will be in charge of the detail design and programming. Personally I doubt even the most promising of these (vanadium, perhaps) is up to the job of pure BEV operation, so we default back to the sort of thing GE tried a decade ago, the issue then being one of cost vs. 'environmental' benefit or perception. Not enough grant money or tax incentive yet!
I still think there is something in LNG as a practical co-fuel, but that is because I have a soft spot for different methods of using cryomethane in transportation -- ways that do not lend themselves compellingly to modern PSR-optimized motive power, anyway. Still ... if you want to use gas for anything other than a synthesis feedstock for liquid fuel, or maybe at the outside a reformer feedstock for fuel-cell hydrogen, that's about the only technology with the necessary safety. Probably best to keep it powering the grid and argue for progressive lineside power sourcing and dual-mode-lite locomotives.
Hopefully we will get up to date on the high-traffic-density mainlines with contemporary electrification.
FEC is a regional railroad with the advantage of having only one route so the ES44C4's are virtually in captive service. On one of the Class 1 roads, such a fleet would be an outlier with all of the issues that come with that status, including what happens when the specialized power strays from the assigned service.
LNG does not have nearly the explosive potential of CNG since it is so cold. Works well for the FEC.
Caldreamer
Florida east coast uses gas successful out of Jacksonville get locos with tender center. Yup gas cheep now. We are largest producer in world thanks to our govt now.
chicagorailsWhat's better now? Gas or electric locos?
If you are talking commuter lines, maybe electric either overhead or battery. For freight, definitly gas. We now have so much natural gas that the prices are dirt cheap and will remain so for a very long time.
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