What’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.
Caldreamer
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.
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.
LNG does not have nearly the explosive potential of CNG since it is so cold. Works well for the FEC.
Caldreamer
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.
[quote user=“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.
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.
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.
At least until the true cost (to the planet) of continued use of fossil fuels is realized. The eventual tax on carbon will price it out of the market. As to what will replace it…??
That has many good first steps. Locations that use a lot of fuel are ripe for first installations. With PSR and PTC those 2 things are major impediments for use. Coupling and uncoupling electric motors to any freight takes too much time under present FRA brake rules. Really wish there could be a way to reduce the times. For Horseshoe it does have the advantage of an up and down profile. Imagine 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 axel inverter set of the electric motor. Then when under CAT pan raised and the unit then provides power to all traction motors. 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.
This type unit will require some engineering to install a possible 20,000 HP capable transformer, power distribution cables between units, control software and cabeling. Also some what higher HP traction motors on the electric loco motor unit. The e
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.
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 o
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.
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.
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.
Connecting the bus should be no more complex than a mid consist fuel tender.
Would need a more robust MU hook-up.
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.
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
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 
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! [:O])
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 –
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.
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.