I was looking over a leasing company roster (HLCX) and noticed that ex BN SD40-2 #7149 was noted as being a natural gas locomotive. Anyone have any kind of information on this locomotive, i.e. who’s decision was it to turn the locomotive to natural gas usage, HLCX, BN, or factory? And wouldn’t it be some what of a problem with additional infustructure (sp?) for the natural gas for a single unit rather than staying with standard diesel?
BN had at least one pair of SD40-2 running on CNG, compress natural gas…with converted tank cars as tenders.
Do a Goggle search on the unit number you have, there are a lot of photos and info still around about them.
No more difficult to “fuel” as a CNG auto, and the infrastructure was not that complicated.
Ed
There is also LNG Locomotives (liqufied natural gas), I have no idea what is more cost effective: desiel, LNG, or CNG…
Does anyone know?
ok, one thing that didn’t show up during the search… why were the units eventually reworked to use standard diesel, rather then continuing to use natural gas?
BN 7149 and BN 7890 were converted by BN in 1991 to a natural gas powered loco and then converted back to a regular SD40-2 in 1997.
BN 7149 was sold to HLCX in June of 1999 and BN 7890 stayed with BN and was eventually painted into BNSF paint later and is still with BNSF.
Does anyone know if the green goats are LNG or CNG?
The goats have a diesel powered generator that constantly recharges the large battery banks, it is neither LNG or CNG.
Probably the biggest drawback, IMHO, would be that , while the infrastructure is not complicated, it probably does not exist at the scale that would let the loco travel the system. I can see an application with a “captive” loco - local switching/industrial, where it can come back to one fuel point on a regular basis.
Sorry got the MK1200Gs mixed up with the green goats.
Thanks for the correction, no wonder I was having a hard time finding them onine and they are LNG.
Dave
No problem, all high visibility cab and pug noses, all ugly!
Agreed!
SD 9s they’re not.
I got to see UPY 2004 up close, and I agree that thing is ugly.
Having worked with MK1500Ds for the last 8 years, I kinda like the look.
Form does follow function.
And my engineer can see us no matter where we ride…
Ed
Perhaps a logical confusion is that RailPower, the Green Goat folks, also are promoting their CINGL concept (which is natural gas).
A major problem with natural-gas locomotives is that the fuel has low energy density (even when liquefied – and when liquefied you need a considerable amount of heat to re-gasify it for combustion). IIRC, you need something like 3.2 times the amount of natural gas for the same hp output from an internal-combustion engine, but the cost of fuel per gallon may even be higher for the natural-gas products as delivered. There are also ‘alternative customers’ for natural gas – including peak power plants and millions of residential users – that run the price up out of all proportion to utility as a transportation fuel.
RailPower has some economic analyses about why their natural-gas design is, overall, cost-competitive with diesels. (You can find some of the material at
http://www.railpower.com/products_td.html
although the following quote from that page may give some pause…)
“The cheaper price of natural gas than diesel, while maintaining similar thermal efficiencies, is what drives the cost savings on the CINGL”
Reading between the lines: Almost all the time, if you don’t require the natural-gas fuel for pollution abatement or special operations, it simply isn’t cost-effective compared to diesel. (And there are better technologies for particulate abatement in diesel exhaust…)
I was under the impression that the pressure drop upon exiting the tank was enough for regasification. Its one of the cooler thing with regards to LNG over CNG in that you don’t have to keep the regulator heated.
Is that right or wrong?
And Ed do you guys still have or are testing a MK2000C?
Dave
Dave: Any time you get pressure drop, you get cooling. Not heat. If you have a compressed material with a very low boiling point, you’ll get a gas coming out, and that gas may be suitable for piping to burners and subsequent ignition/combustion. But it will, of necessity, be colder than what comes out of the tank.
LNG, also by definition, is a cryogenic fuel: it was likely first compressed, then chilled so that it behaves as a liquid in handling and storage – it inherently has low pressure and high density, so you get lots of combustion energy in a relatively small space. But you now need really competent insulation (multishielded vacuum bottles, high-performance foams, all that wonderful stuff from the Space Age) to keep it in liquid form, and you have to put heat back into it to return it to combustible natural gas at or near room temperature… or arrange to inject and burn it as a cryogenic liquid, which is how the SSME burns its oxygen and hydrogen, and perhaps more to the point how the methane… that’s the major ingredient in natural gas… is burned in a PDWE. Unfortunately, the advantages of cryogenic fuel injection do NOT particularly apply to railroad applications in a cost-effective, or even particularly flexible in service, manner.
If you intend to burn LNG in any kind of engine that requires carburetion, you will have to regasify it. Yes, that step happens before you pass the gas through a regulator (to meter it for proper carburetion or combustion-air metering), and yes, you can do it with “waste” heat, for example from the engine exhaust or from a regenerative burner (using the same principle of the burners you see on some hot-air balloons). Not difficult to get a back-of-the-envelope calculation of the heat required – take the fuel feed in gph or whatever, convert to mass, and look at the temperature rise from -256F up to ambient. As the LNG boils off, it ‘autorefrigerates’ the remaining fuel, which will reduce the pressure of the vapor above the liquid and h
I love this site!
One more question sir:
In the past in locomotive applications have they converted existing diesel engines to CNG or have they started with a clean slate? It seems in the medium to heavy truck categories the conversions were mediocre at best, and the purpose built (John Deere 8.1s for example) are very close to an equivelent sized diesel power-wise.
As always thanks for the answers, knowledge is power…
Dave
First: the CINGL locomotive uses a gas-turbine powerplant, which is almost certainly built using modern ‘microturbine’ methods and materials… a high percentage of ceramics, self-adjusting magnetic bearings, etc.
On the question of locomotive conversions: there have been multiple attempts at ‘dual-fuel’ diesel/CNG locomotives. Bombardier did extensive research in the late 1980s (using the Alco/MLW 251 as the principal platform) – results from this are available. A resource that, I think, will have answers for your questions is:
www.tc.gc.ca/tdc/publication/pdf/13400/13470e.pdf
My understanding is that the effective power output of the engine can be made very close (with volumetric concerns, and to an extent the ‘clean burn’ desired at high fuel rates when operating in CNG mode for pollution abatement, being the principal limits on developed hp in gas mode). Keep in mind, though, that this is a VERY different thing from saying that the fuel cost will be comparable for equivalent developed power.
My suspicion is that it wouldn’t pay to design ‘clean-slate’ CNG engines for locomotive service alone; there’s not enough amort for expected production runs vs. relatively simple conversions of existing engine tech. You will note that converting a 4-cycle diesel to CNG spark ignition, with modern ignition-timing methods (cf. HEI gasoline-engine tech), involves only a different set of top-ends on the cylinder heads/power packs – lowered compression ratio and holes for spark being the things added. Situation is a bit more complicated for EMD 2-cycles, as you either pressurize the crankcase with carbureted gas (!!!) or have to arrange separate sets of ports for the gas mixture and the scavenge air, which in turn would require some different, probably CNC, machining on the powerpack assemblies and perhaps some additional fittings and components on the inside and outside of the crankcase.
The engines classically used in American locomotives turn s
Dave,
The MK6201, a six axel 2000hp one off demo, was sold after our lease ran out,it is in Florida, last I heard.
Wish we could have kept it…loved switching with it!
Ed
Being an engineer (not the kind that operates locomotives) I agree with the function having precedence over form but I sure think those things are ugly.